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Best Practice Guideline - A3: Water Management in Hydrometallurgical Plants -- July 2007

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Published by

Department of Water Affairsand Forestry

Private Bag X313

PRETORIA

0001

Repblic of Soth Africa

Tel: (012) 336-7500

Copyright reserved

No part of the pblication

may be reprodced in

any manner withot

fll acnowledgement

of the sorce

T rport o ct a:

Department of Water Affairs and Forestry, 2007. Best Practice Gideline A3: Water

Management in Hydrometallrgical Plants.

dcamr:

Althogh the information contained in this docment is presented in good faith and

believed to be correct, the Department of Water Affairs and Forestry maes no

representations or warranties as to the completeness or accracy of the information,

which is only based on actal information received, and maes no commitment to

pdate or correct information.

Contant:

Plles Howard and de Lange Inc.

P O Box 861

AuCkLAND PARk

2006Repblic of Soth Africa

Golder Associates Africa (Pty) Ltd

P O Box 6001

HALFWAY HOuSE

1685

Repblic of Soth Africa

isbN 978-0-9802679-0-7

stat Final Jly 2007




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This docment is the third in a series of the following Activity Best Practice Gideline

docments:

BPG A1: Small-scale Mining

BPG A2: Water Management for Mine Reside Deposits

BPG A3: Water Management in Hydrometallurgical Plants

BPG A4: Polltion Control Dams

BPG A5: Water Management for Srface Mines

BPG A6: Water Management for undergrond Mines

dOCuMeNT

iNdeX

Ator

Ms Palette Jacobs (Palette Jacobs Conslting)

Mr William Plles (Golder Associates)

spcat

Ms Jennifer L. Broadhrst (private)

Ms kerry Slater (private)

Ms Riana Mnni (DWAF)

Solomon Tsheo (DWAF)

Since 1999 a nmber of steering committee meetings and staeholder worshops were held

at varios stages of the development and drafting of this series of Best Practice Gidelines for

Water Resorce Protection in the Soth African Mining Indstry.

We are deeply indebted to the steering committee members, ofcials of the Department of

Water Affairs and Forestry and staeholders who participated in the meetings and staeholder

worshops held dring the development of the series of Best Practice Gidelines for their

inpts, comments and ind assistance.

The Department wold lie to acnowledge the athors of this docment, as well as the

specialists involved in the process of developing this Best Practice Gideline. Withot their

nowledge and expertise this gideline cold not have been complemeted.

ACKOWledGe-

MeNTs




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APPROVAlsT ocmnt approv t dpartmnt of Watr Affar an

Fortr




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PReFACeWater is typically the prime environmental medim (besides air) that is affected by mining

activities. Mining adversely affects water quality and poses a signicant risk to South Africa’s

water resorces. Mining operations can frther sbstantially alter the hydrological and

topographical characteristics of the mining areas and sbseqently affect the srface rnoff,soil moistre, evapo-transpiration and grondwater behavior. Failre to manage impacts on

water resorces (srface and grondwater) in an acceptable manner throghot the life-of-

mine and post-closre, on both a local and regional scale, will reslt in the mining indstry

nding it increasingly difcult to obtain community and government support for existing and

ftre projects. Conseqently, sond management practices to prevent or minimise water

polltion are fndamental for mining operations to be sstainable.

Pro-active management of environmental impacts is reqired from the otset of mining activities.

Internationally, principles of sstainable environmental management have developed rapidly in

the past few years. Locally the Department of Water Affairs and Forestry (DWAF) and the

mining indstry have made major strides together in developing principles and approaches for

the effective management of water within the indstry. This has largely been achieved throghthe establishment of joint strctres where problems have been discssed and addressed

throgh co-operation.

The Bill of Rights in the Constittion of the Repblic of Soth Africa, 1996 (Act 108 of 1996)

enshrines the concept of sstainability; specifying rights regarding the environment, water,

access to information and jst administrative action. These rights and other reqirements are

frther legislated throgh the National Water Act (NWA), 1998 (Act 36 of 1998). The latter is

the primary statte providing the legal basis for water management in Soth Africa and has

to ensre ecological integrity, economic growth and social eqity when managing and sing

water. use of water for mining and related activities is also reglated throgh reglations that

were pdated after the promlgation of the NWA (Government Notice No. GN704 dated 4 Jne

1999).

The NWA introdced the concept of Integrated Water Resorce Management (IWRM),

comprising all aspects of the water resorce, inclding water qality, water qantity and the

aqatic ecosystem qality (qality of the aqatic biota and in-stream and riparian habitat). The

IWRM approach provides for both resorce directed and sorce directed measres. Resorce

directed measres aim to protect and manage the receiving environment. Examples of resorce

directed actions are the formlation of resorce qality objectives and the development of

associated strategies to ensre ongoing attainment of these objectives; catchment management

strategies and the establishment of catchment management agencies (CMAs) to implement

these strategies.

On the other hand, sorce directed measres aim to control the impacts at sorce throgh

the identication and implementation of pollution prevention, water reuse and water treatment

mechanisms.

The integration of resorce and sorce directed measres forms the basis of the hierarchy

of decision-taking aimed at protecting the resorce from waste impacts. This hierarchy is

based on a precautionary approach and the following order of priority for mine water and waste

management decisions and/or actions is applicable:




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ResOuRCe PROTeCTiON ANd WAsTe

MANAGeMeNT hieRARChy

stp 1: Poton Prvnton

↓stp 2: Mnmaton of impact

Water rese and reclamation

Water treatment

↓stp 3: dcarg or poa of wat

an/or wat watr

Site specic risk based approach Pollter pays principle

The docmentation describing Watr Rorc

Protcton an Wat Managmnt in Soth Africa

is being developed at a nmber of different levels, as

described and illstrated in the schematic diagram on

this page.

The overall Resource Protection and WasteManagement Policy sets ot the interpretation of

policy and legal principles as well as fnctional and

organisational arrangements for resorce protection and

waste management in Soth Africa.

Operational policies describe the rles applicable

to different categories and aspects relating to waste

discharge and disposal activities. Sch activities from

the mining sector are categorised and classied, based

on their potential riss to the water environment.

Operational Guidelines contain the reqirements for

specic documents e.g. licence application reports.

Best Practice Guidelines (BPG’s) dene and document

best practices for water and waste management.

scmatc dagram of t Mnng sctor Rorc Protcton an Wat Managmnt

stratg




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The DWAF has developed a series of bt Practc

Gn (BPGs) for mines in line with International

Principles and Approaches towards sstainability. The

series of BPGs have been groped as otlined below:

besT PRACTiCe GuideliNes dealing with aspects of

DWAF’s water management hieRARChy are prefaced

with the letter h. The topics that are covered in these

gidelines inclde:

• H1. Integrated Mine Water Management

• H2. Pollution Prevention and Minimisation of Impacts

• H3. Water Reuse and Reclamation

• H4. Water Treatment

besT PRACTiCe GuideliNes dealing with GeNeRAl

water management strategies, techniqes and tools,

which cold be applied cross-sectoral and always

prefaced by the letter G. The topics that are covered in

these gidelines inclde:

• G1. Storm Water Management

• G2. Water and Salt Balances

• G3. Water Monitoring Systems

• G4. Impact Prediction

besT PRACTiCe GuideliNes dealing with specic

mining ACTiViTies or AsPeCTs and always prefaced

by the letter A. These gidelines address the prevention

and management of impacts from:

• A1 Small-scale Mining

• A2 Water Management for Mine Residue Deposits

• A3. Water Management in Hydrometallurgical Plants

• A4 Pollution Control Dams

• A5 Water Management for Surface Mines

• A6 Water Management for Underground Mines

The development of the gidelines is an inclsive

consltative process that incorporates the inpt from

a wide range of experts, inclding specialists within

and otside the mining indstry and government. The

process of identifying which BPGs to prepare, who shold

participate in the preparation and consltative processes,

and the approval of the BPGs was managed by a Project

Steering Committee (PSC) with representation by ey

role-players.

The BPGs will perform the following fnctions within the

hierarchy of decision maing:

• Utilisation by the mining sector as input for compilingwater se licence applications (and other legally

reqired docments sch as EMPs, EIAs, closre

plans, etc.) and for drafting licence conditions.

• Serve as a uniform basis for negotiations through the

licensing process prescribed by the NWA.

• Used specically by DWAF personnel as a basis for

negotiation with the mining indstry, and liewise by

the mining indstry as a gideline as to what the DWAF

considers as best practice in resorce protection and

waste management.

• Inform Interested and Affected Parties on goodpractice at mines.

The information contained in the BPGs will be transferred

throgh a strctred nowledge transfer process, which

incldes the following steps:

• Workshops in key mining regions open to all interested

parties, inclding representatives from the mining

indstry, government and the pblic.

• Provision of material to mining industry training

grops for inclsion into standard employee training

programmes.• Provision of material to tertiary education institutions

for inclsion into existing training programmes.

• Provision of electronic BPGs on the DWAF Internet

web page.




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CONTeNTsdOCuMeNT iNdeX ii

ACKOWledGeMeNTs ii

APPROVAls iii

PReFACe iV

AbbReViATiONs ANd TeRMiNOlOGy iX

1 iNTROduCTiON ANd ObJeCTiVes 11

2 GeNeRAl PRiNCiPles ANd CONsideRATiONs 14

3 leGAl FRAMeWORK 18

3.1 Focs and role of DWAF . . . . . . . . . . . . . . . . . . . . . . 18

3.2 National Water Act . . . . . . . . . . . . . . . . . . . . . . . . . 18

3.3 DWAF Waste Management Series - Minimm Reqirements 19

3.4 Best Practice Gideline series . . . . . . . . . . . . . . . . . . . 19

4 CONsideRATiONs WiThiN The MiNe liFe-CyCle 20

4.1 Exploration, prospecting, planning, feasibility and design phase 21

4.2 Commissioning and operational phase . . . . . . . . . . . . . 23

4.3 Decommissioning, closre and post-closre phase . . . . . . 23

5 FiNANCiAl CONsideRATiONs (sTePs 1 ANd 2) 24

5.1 Water, a ey bsiness asset (Step 1) . . . . . . . . . . . . . . . 25

5.2 Tre vale and cost of water (Step 2) . . . . . . . . . . . . . . 25

6 iNFORMATiON GATheRiNG (sTePs 3, 4 ANd 5) 28

6.1 Site and process nowledge (Step 3). . . . . . . . . . . . . . . 28

6.2 Water and salt/load balances (BPG G2: Water and salt balances)

(Step 4) . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 30

6.3 Mine/plant water sers (Step 5) . . . . . . . . . . . . . . . . . . 30.

7 hOuseKeePiNG ANd WATeR MANAGeMeNT sysTeMs

(sTeP 6) 31

7.1 Minimize water se/ water conservation . . . . . . . . . . . . . 31

7.2 Water segregation . . . . . . . . . . . . . . . . . . . . . . . . . 32

7.3 Storage of materials . . . . . . . . . . . . . . . . . . . . . . . . . 32

7.4 High contamination ris areas . . . . . . . . . . . . . . . . . . . 33

7.5 Storm water management (BPG G1: Storm water management) 33

7.6 Cleaning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34

7.7 Eqipment and maintenance . . . . . . . . . . . . . . . . . . . 34

7.8 Sstainability . . . . . . . . . . . . . . . . . . . . . . . . . . . . 34




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8 WATeR QuAliTy ANd CONsTiTueNTs OF CONCeRN

(sTeP 7) 35

8.1 Minimize generation of contaminants . . . . . . . . . . . . . . . . . . . . . . . . . . . . 36

8.1.1 Review intae/inpt/raw materials . . . . . . . . . . . . . . . . . . . . . . . . . 36

8.1.2 Optimize polltion prevention and redction at sorce. . . . . . . . . . . . . . 37

8.2 Water qality reqirements for mine/plant water sers . . . . . . . . . . . . . . . . . . 37

8.3 Monitoring, maintenance, inspections and adits. . . . . . . . . . . . . . . . . . . . . . 38

9 WATeR Reuse ANd ReClAMATiON (sTeP 8) 39

10 PROCess ChANGes OR CleANeR TeChNOlOGy (sTeP 9) 42

10.1 Need and signicance . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

10.2 Implementation . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 43

10.3 Barriers preventing cleaner prodction. . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

10.3.1 Economic barriers/constraints. . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

10.3.2 Technology barriers. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 44

10.3.3 Legislative barriers/pressres . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

10.4 Overcoming barriers . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

10.4.1 Governmental intervention . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

10.4.2 Edcation and training . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

10.4.3 Improved planning . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 45

11 iNTeGRATed WATeR ANd WAsTe MANAGeMeNT PlAN (sTePs 10 ANd 11) 46

12 ReFeReNCes ANd FuRTheR ReAdiNG 52

FiGuRes

Figre 1.1 Best Practice Gidelines . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 1

Figre 2.1 Stepwise procedre for water management at a hydrometallrgical processing plant. 4

Figre 4.1 Considerations in the mine life-cycle . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 10

Figre 4.2 Process design constraints (Marr, 2003) . . . . . . . . . . . . . . . . . . . . . . . . . . . 11

APPeNdiCes

APPENDIX A: WATER QuALITY ISSuES. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 54

APPENDIX B: VARIOuS HYDROMETALLuRGICAL PROCESSES. . . . . . . . . . . . . . . . . . . . 58

APPENDIX C: EXAMPLE OF DETAILED RISk ASSESSMENT PROCESS AT PLANT

DESIGN STAGE. . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 71

APPENDIX D: CHECkLIST . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . . 76




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AMD: Acid mine drainage

Axiliary inpts: Materials added to the process to help or assist the process or increase

the speed at which it occrs.

Berm: A ban/border (raised or piled p area) constrcted (from soil/cement)

to prevent water owing over it thereby forcing the water to ow along a

specic path as directed by the berm.

BPG: Best Practice Gideline (docments in this series)

Bund: An articial embankment to ensure containment in a desired area.

Classier: Process to arrange or distribute in classes.

COC: Contaminants of concern

Chpt: Chapter

DWAF: Department of Water Affairs and Forestry

ECA: Environment Conservation Act, 1989 (Act 73 of 1989)

Filters: Filtration is the physical separation used for the removal of ne

suspended solids. May be effected in granular media lters (e.g. sand

lter) or membrane lters (e.g. Nanoltration).

Flotation: The physical separation and removal of sspended material that settles

slowly by bbbling air throgh the soltion and allowing particlates to

oat to the surface on air bubbles, where it is skimmed off.

Grinding: The process throgh which the particle size is redced by crshing

between two hard srfaces. The physical characteristics are thereforechanged (smaller particles/powder) bt not the chemical characteristics.

Hydrometallrgical: Incldes milling and grinding circits; separation circits (magnetic

or other); rening circuits; classiers, hydrocyclones, screens, lters,

thickeners, otation processes, electro-winning, leaching, solvent

extraction, metal recovery and precipitation

IWWM: Integrated water and waste management

IWWMP: Integrated water and waste management plan

Leaching: To let liqid percolate throgh some material with the objective of

removing solble constitents from the material and captring them in

the liqid phase. Leachate is the reslting liqid containing the dissolvedsbstance.

Milling: See grinding. using a mill for the grinding process.

NEMA: National Environmental Management Act, 1998 (Act 107 of 1998)

NWA: National Water Act, 1998 (Act 36 of 1998)

PGM: Platinm Grop Metal; incldes platinm, palladim, rhodim, rthenim,

osmim and iridim

Precipitation: The process dring which a sbstance (the precipitate) is separated from

AbbReViATiONs

& TeRMiNOlOGy




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the liqid (throgh the action of a chemical reagent or heat) in which it was previosly dissolved

and deposited in the solid state.

Pyrometallrgy: The branch of extractive metallrgy in which processes employing chemical reactions at elevatedtemperatres are sed to extract metals from raw materials, sch as ores and concentrates, and

to treat recycled scrap metal.

Raw water: Water obtained from otside the operations; it may inclde water from the local service provider

(mnicipality), bl service provider or another water ser and may be of a potable qality

(drining water spply from mnicipality) or water treated to a certain degree (treated sewage

water)

Rening: To free from impurities; to make purer or of a ner quality; to purify or cleanse.

Separation: The separation of material into two streams based on some physical characteristic sch as its

magnetic properties of its specic gravity

Thickener: It increases the density of the solution. A non-lter device for the removal of liquid from a

liqid-solids slrry to give a dewatered (thicened) solids prodct; can be by gravity settling or

centrifgation

unreactive: Materials that will not readily dissolve in water or react with water

WRC: Water Research Commission




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The Hydrometallrgical Processing Plant is an integral part of the mining operation on many

mines, inclding gold, coal and platinm. Hydrometallrgical processing plants typically featre

as a central component of the mining operation in that these receive the raw ore from the mine

and may produce the saleable product, the solid waste streams and a signicant portion of the liquid efuent. While the operations and water balance of the average hydrometallurgical

processing plant are integrally lined with the preceding mining operation and the sbseqent

reside disposal facility and its associated retrn water systems, there are particlar featres

that relate to water management within the hydrometallrgical processing plant itself. This

Best Practice Guideline (BPG) focuses specically on water management issues within

the hydrometallrgical processing plant, while water management isses within the mining

operations are covered in BPG A5: Water management for Surface Mines and BPG A6:

Water Management for Underground Mines and water management associated with a reside

disposal facility is covered in BPG A2: Water Management for Mine Residue Deposits.

This BPG (BPG A3: Water Management in Hydrometallurgical Plants) therefore only

deals with water management isses within the bondary fence of the hydrometallrgicalprocessing plant (see Figre 1.1 below) and excldes water management associated with the

mining process/operation and the reside disposal activities. This BPG ths starts when ore

(inclding water/moistre) and water from the mining operation arrives at the hydrometallrgical

processing plant for processing and nishes when residue (tailings) leaves the processing site

(generally via a pipeline) for disposal.

1iNTROduCTiON

ANd ObJeCTiVes

The type of hydrometallrgical processing

plant that is addressed in this BPG is one

that focses on the nit processes typically

encontered in sch a plant and wold inclde:

milling and grinding circits; separation

circuits (magnetic or other); rening circuits;

classiers, hydrocyclones, screens, lters,

thickeners, otation processes, electro-

winning, leaching, solvent extraction, metal

recovery and precipitation.

Hydrometallrgical processing plants need

to operate within an external environment

where water is becoming an increasingly

scarce and valable resorce with

competing demands, primarily from the need

to satisfy the demand for hman se and

ecological functioning. As a signicant user

of water and a prodcer of water containing

waste, the minerals indstry, with their

hydrometallrgical processing plants have an

Fgr 11: bt practc gn




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important role to play in ensring that water is conserved

and sustainably used and managed to the benet of all

the water sers. The mining and minerals indstry is

already exposed to the tre vale of water in having toconfront areas where water is in short spply, or where

poor qality water needs to be treated before it can be

sed or discharged. In addition, legislative developments

sch as the waste discharge charge system are set to

have a major inuence in dictating the economics of

water spply, water treatment and discharge.

Within this external environment, hydrometallrgical

processing plants are reqired to tighten p the degree

of water rese and redce the amont of wastewater

discharged. This obviously has signicant implications

for water qality within the hydrometallrgical processingplants’ water circuits, both in terms of potential effects on

the efciency of various unit processes within the plant,

as well as on the eqipment that maes p the plant in

terms of scaling and corrosion. To ensre that improved

water management within hydrometallrgical processing

plants avoids, or at least signicantly reduces, the

potential negative effects, while still complying with

the strategic imperatives imposed by the external

environment within which these plants operate, it is

necessary that water management operations are rmly

based on sond and correct principles. It is the objective

of this BPG to provide gidance on these ey isses.

Hydrometallrgical processing operations, if not managed

correctly, have the potential to negatively impact on the

srronding environment and case environmental

damage on nmeros fronts. Beginning with the

exploration of prospective sites, through to the rening

and beneciation of minerals, many contaminating wastes

are generated both directly and indirectly. If not managed

correctly, these waste streams may pose serios threats

to ecosystems and to hman qality of life, and cold

also deteriorate resorces, particlarly water and soil. It

is therefore important to minimize all polltants, inclding

air emissions, wastewater discharges and solid wastesas well as energy and water consmption.

An integrated water and waste management (IWWM)

approach is based on the DWAF water management

hierarchy for decision-taking and focuses rstly on

waste and polltion prevention/avoidance. If complete

prevention is not possible, waste and polltion

minimization becomes the next area of focs and this

may inclde the economic redction of waste stream

volmes and se of chemicals via process design.

Thereafter rese (recycling) and reclamation (recovery)

becomes important and lastly, if all of the above have

been considered, treatment (redction of volme or

hazardosness) and environmentally safe disposal

remain the only options left to ensre the minimisation of the environmental impact.

Waste creation needs to be controlled dring the

prodction processes by integrating a series of highly

effective polltion prevention measres, state-of-the-

art environmental management practices and efcient

treatment technologies/strategies in the pollting

sections of the operation. Individally and/or collectively,

these minimization strategies will redce the qantities

of polltants released to small, manageable amonts,

and will also enable treatment and removal of any toxic

chemicals that may otherwise have been destined for discharge into the environment. In addition to preserving

the environment, liabilities and operational cost will be

redced throgh sch practices.

The prevention and management of polltion from

hydrometallrgical processing plants is based on the

environmental and water management systems in place

on these sites as well as the prodction processes.

These management systems shold inclde a practical

environmental policy, organizational procedres,

research and development programmes, environmental

responsibilities, allocation of dedicated resorces and

spport, training, monitoring, management and treatment

and operational adjstments and control.

This BPG is specically aimed at water containing waste

within hydrometallrgical processing plants associated

with all types of mines and can also be applied to small-

scale mines if simplied (refer to BPG A1: Small-scale

Mining ). Pyrometallrgical and smelter operations are

not considered, althogh many of the principles and

procedres covered in this BPG may be applicable to

sch operations. This BPG will also draw extensively on

other BPGs that have already been prodced and will

cross-reference to these BPGs wherever it is appropriateto do so.

The primary objectives of this docment are formlated

as follows:

• To promote a strategic water management approach

at hydrometallrgical processing plants that views and

manages water as a ey bsiness asset with social,

cltral, environmental and economic vale.

• To provide a practical and logical process whereby

water management within hydrometallrgical




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3

processing plants can be optimized.

The rst objective is a broad strategic objective, taken

from a strategic framewor docment prepared by theMinerals Concil of Astralia in 2006. This objective

is entirely consistent with sstainable development

imperatives and is considered appropriate in a water-

scarce contry sch as Soth Africa where there is

increasing competition and demands on the scarce and

limited water resorce. The second objective addresses

the practical isses and gidance that will be reqired to

give effect to the rst objective.

The layot of the docment is as follows:

• Chapter 2: General principles and considerations

for water management on a hydrometallrgicalprocessing plant and the stepwise procedre to follow

for efcient and effective water management on a

hydrometallrgical processing plant.

• Chapter 3: Legal framework and legislation

to consider in terms of water management at a

hydrometallrgical processing plant.

• Chapter 4: Considerations within the different

phases of the mine life-cycle and the importance

to incorporate considerations into the planning and

design phases already.

• Chapter 5: Financial considerations assessingthe tre cost and vale of water as well as looing at

water as a ey bsiness asset.

• Chapter 6: Information gathering to gain

nowledge of the site and process, do water and salt

balances and understand the mine/plant water users’

reqirements.

• Chapter 7: Hoseeeping and water management

systems aiming to:

- conserve water;

- segregate water of different qalities;

- store material in the correct manner;- deal with high contamination ris areas;

- manage storm water;

- clean spillages efciently and effectively;

- maintain and repair eqipment; and

- mae the operation sstainable.

• Chapter 8: Water quality and constituents of

concern specically preventing the deterioration

of water qality by minimizing the generation of

contaminants and establishing the water qality

reqirements of the mine/plant water sers.

• Chapter 9: Water reuse and reclamation smmary

as per details contained in BPG H3: Water Rese and

Reclamation.

• Chapter 10: The need and signicance of process

changes or cleaner technology, the implementation

of changes or technologies, barriers preventing

implementation and how to overcome these barriers.

• Chapter 11: Integrated water and waste

management plan compilation from information

collected and strategies implemented by following the

process stiplated in this BPG.




____________________________________________________________________________________________________________________________________

4

Figre 2.1 below shows an effective stepwise procedre that shold be followed in a

hydrometallurgical processing plant to ensure the efcient management of water. Details

pertaining to the diagram are discssed frther on in the docment in the different Chapters

as indicated.

2

GeNeRAl

PRiNCiPles ANd

CONsideRATiONs

Fgr 21: stpw procr for watr managmnt at a ro-

mtargca procng pant




____________________________________________________________________________________________________________________________________

5

In order to spport the two primary objectives of this

BPG as listed in Chapter 1, a nmber of ey principles or

considerations are identied that need to be considered

when implementing best practice water management

within hydrometallrgical processing plants.

unrtan t tr cot an va of

watr: (Captr 5)

The tre cost and vale of water incldes all direct costs

of water se on site as well as its vale as a bsiness

asset reqired for contined operation, for example:

• Cost of exploration and extraction of groundwater;

• Social, cultural, environmental, and economic

feasibility stdy costs;

• Waste stream disposal costs;

• Cost of water supply;

• Reticulation costs such as pumping, storage, power

consmption;

• Water treatment costs;

• Mitigation and remediation costs in the event of

spillage;

• Construction and rehabilitation costs of engineering

wors e.g. river diversions, clean/dirty water diversions

etc;• The value of ecosystem services reliant on the same

water spply;

• Competing social and industry demands on the same

resorce;

• Competing industry demand for the same resource;

• Economic value to allow production and processing to

tae place; and

• Loss of income, jobs or market share if there are

prodction ct-bacs and interrptions as a reslt of

water excess or shortage.

App gnra “goo” okpng

an opratng practc: (Captr 7)

• Avoid cross-contamination of materials and chemicals

by eeping the wor area clean and organized;

• Segregate waste streams (consider piping and storage

facilities) based on their level of contamination.

• Install proper safeguards (bunded areas, diversion

berms, concrete paving) and implement better

cleanp practices (washing, sweeping etc);

• Consider general layout of the site and process plant

as well as placement of facility;

• Know and have a good understanding of the plantand water circits.

Optmz poton prvnton an

rcton at orc: (Captr 7)

• Bund, contain and recycle certain high risk areas;

• Roof areas to prevent water inltration;

• Concrete areas to prevent seepage into underlying

grondwater;

• Slope areas to minimize erosion and maximize

rnoff.

• Divert storm water around major pollution sources.

Optmz watr managmnt tm:

(Captr 7)

• Design and operate for the separation of water circuits

based on the level of contamination and possible ses.

In particlar, ensre a separation between process

water circits and the storm water system and ensre

that process spillages cannot nd their way into storm

water systems;

• Develop and maintain an accurate water and

contaminant balance for all water circits – not only

for potable water;

• Based on knowledge of which are the primary

contaminants of concern (COC) for that particlar

process plant, develop contaminant balances for

each COC and identify potential options for redction

of contaminant load;

• Dene the water quality requirements of the different

water users within a process plant. Dene the

worst possible water qality that each ser can se

withot experiencing process or water qality related

problems (e.g. corrosion and scaling);• For storm water management, make provision for

ftre sealing of areas and constrction of roofs that

case increase in volme of rnoff;

• Keep clean water clean – (refer to BPG G1: Storm

Water Management ) by reroting grondwater

springs and srface water streams to prevent contact

with contamination/polltion sorces;

• Construct diversion berms and channels to carry clean

rnoff away from solvent exchange, leach and tailings

disposal areas or other possible polltion sorces;




____________________________________________________________________________________________________________________________________

6

• Control erosion through measures such as retention

ponds to intercept rnoff and protection of stream

bans;

• Manage process water. Contain dirty water (refer to

BPG G1: Storm Water Management ) in bnded

areas for recycling in the bnded area or channel

contaminated runoff and spills in drains to articial

basins and srge ponds (Polltion Control Dams) for

containment and possible rese and/or reclamation

(refer to BPG H3: Water Reuse and Reclamation).

• Separate circuits to prevent cross-contamination of

circits;

• Setup water management systems in the different

phases of development to ensre sstainability. Water

management systems incorporated dring the design

and constrction phases of an operation can be tailor-

made to the application. With an existing operation,

the water management system has to consider the

existing system infrastrctre.

unrtak npcton/montorng/

atng an mantnanc: (Captr 8)

• Ensure that equipment/machinery inspection and

maintenance schedles are followed and that

eqipment/machinery is in pea woring order to

prevent wastage of raw materials and/or loss of prodction/processing time thereby ensring prodct

is not compromised;

• Ensure data availability on plant pollutants (refer to

BPG G3: Water Monitoring Systems);

• Ensure sufcient water ow meters are installed,

maintained and monitored.

Rvw rorc ntak/npt/raw

matra: (Captr 8)

• Minimize or reduce raw material use;

• Use lowest possible chemical concentrations at which

process can operate effectively throgh tight process

control measres to prevent overdosing;

• Control purchasing, handling and storing of

materials;

• Substitute raw and auxiliary materials with less

harmful ones that can be more efciently recycled

ths feedstocs with fewer inherent by-prodcts;

• Consider products and/or catalysts with longer lives

and rese possibilities;

• Minimize raw water intake into process (water

conservation principle);

• Consider novel energy sources and efcient energyse;

• Avoid extraneous water streams being introduced to

the process such as off-site runoff nding its way onto

the site.

Optmz r an rcamaton

(rccng an rcovr): (Captr 9)• Minimize waste by retrieving/recovering usable

process materials and resorces from waste

streams;

• Convert in-plant waste and wastewater streams toclean feed, ths allowing for reclamation of chemicals

and water for rese in the plant (refer to BPG H3:

Water Reuse and Reclamation);

• Recycle process spillages as close as possible to

their sorce and do not allow to mix into one mixed

contaminated waste;

• Evaluate waste streams for properties that make

them sefl rather than for properties that render

them wastewater streams;

• Introduce waste into external recycling networks:

industrial ecology. One industry’s waste may become

another industry’s raw material;• Consider new uses for otherwise valueless byproducts.

Reclaim byprodcts to sell;

• Save money through more efcient use of valuable

resorces (sch as water and raw materials) and

redced treatment and disposal cost for waste.

invtgat proc or tcnoog

modications: (Chapter 10)

• Modify products and technologies to eliminate

nnecessary prodction steps;

• Modify processes to minimize waste production and

resorces se;

• Improve process selectivity and/or conversion;

• Operate at lower temperatures and/or pressures to

save energy and redce the nmber of processes

reqired to create these high temperatre/pressre

conditions;

• Implement efcient equipment design;

• Consider innovative unit operations and innovative

process integration;




____________________________________________________________________________________________________________________________________

7

• Avoid heat degradation of reaction products and

eliminate leas and fgitive emissions;

• Perform product life cycle assessment (LCA)

inclding process/activity, extraction, processing,

manfactring, recycling and disposal.

Conr opton for appcaton of

canr tcnoog: (Captr 10)

• Evaluate the need and signicance of cleaner

technology to achieve higher prodction rates,

improve product quality, increase operating efciency,

redce environmental impact, redce cost, ensre

higher percentage on-line time and safe operating

conditions;

• Assess the characteristics of cleaner technology;

• Implement cleaner technology in different areas of

bsiness sch as policy development and instittional

relations, environmental and social impact

assessment, technological development, company

strategy and edcation, research and training. Steps

to implement;

• Applications (examples);

• Review barriers such as economic, technologic and

legislative barriers that prevent the implementation of

cleaner technology;

• Overcome barriers and implement cleaner technologythrogh governmental intervention, edcation and

training and improved planning.

Watr an wat managmnt

programm: (Captr 11)

• Ensure the programme is organized, comprehensive

and represents a continos effort to systematically

redce waste generation;

• Include pre-audit phase (adequate resources,

commitment, objectives, scope, employee

involvement), adit phase (data and informationcollection, cost acconting) and feasibility analysis

(technology transfer, continos review);

• Improve environmental auditing and implement

environmental policies to achieve improved

environmental goals;

• Shift emphasis of training programmes (from treatment

to prevent, minimize and control);

• Redesign plants to better accommodate wastes;

• Setup baseline and continual monitoring (refer to

BPG G3: Water Monitoring Systems) of grond,

srface and process water as well as eqipment and

the sbseqent implementation of action plans based

on the reslts.




____________________________________________________________________________________________________________________________________

8

31 Foc an ro of dWAF

The Department of Water Affairs and Forestry (DWAF) is the cstodian of all water resorces in

Soth Africa and therefore responsible for the protection of these water resorces. The protection

of these resorces incldes preventing deterioration of water qality in these resorces. From

this perspective, DWAF generally focses on the impact a hydrometallrgical processing

plant has on the water resorces and srronding environment, ths otside the plant area.

DWAF is therefore generally not too interested in the details pertaining to the site/plant and

hydrometallrgical process. It is only once it has been established that the hydrometallrgical

processing plant does in fact negatively impact on the srronding environment and water

resorces that DWAF becomes concerned with the operation and water management within

the bondaries of the plant. At this stage DWAF may investigate water management on the

hydrometallrgical processing plant to establish the origin of the impact noted on srronding

water resorces.

In terms of any mine hydrometallrgical processing plant and its water and waste management,the following legislation shold be considered as a minimm and these can be obtained from

internet sites (http://www.acts.co.za or http://www.info.gov.za/gazette/acts):

• Environment Conservation Act, 1989 (Act 73 of 1989) with GN R1182 and GN R1183.

• National Environmental Management Act, 1998 (Act 107 of 1998).

• Minerals and Petroleum Resources Development Act, 2002 (Act of 28 of 2002).

• National Water Act, 1998 (Act 36 of 1998).

• Water Act, 1956 (Act 54 of 1956) (repealed) with GN R1560 re dams with a safety risk.

• Water Services Act, 1997 (Act 108 of 1997).

32 Natona Watr ActThe National Water Act of 1998, Act 36 of 1998 (NWA) is the principal legal instrment relating

to water resorce management in Soth Africa and it is obtainable from the DWAF internet site

(http://dwaf.gov.za/docments). The following is of particlar importance:

• Chapter 3, Part 4 states that anyone who owns, occupies, controls or uses land is deemed

responsible for taing measres to prevent polltion of water resorces.

• Chapter 4 deals with water use regulation;

• Chapter 12 deals with water management in terms of dam safety;

• Section 19 deals with water management at mines in terms of pollution prevention and

control;

• Section 21 states the water uses requiring authorization;

• Section 26 (1) provides for the development of regulations requiring monitoring, measurement

and recording as well as the effects to be achieved throgh management practices prior to

discharge/disposal.

Rgaton on of watr for mnng an rat actvt am

at t protcton of watr rorc

Government Gazette 20118 (volme 408) notice 704 (GN 704), pblished on 4 Jne 1999,

stiplates reglations on the se of water for mining and related activities aimed at the protection

of water resorces. The following conditions are worth noting here:

3leGAl

FRAMeWORK




____________________________________________________________________________________________________________________________________

9

• Condition 4 regarding restrictions on the location of

mining activities.

• Condition 5 regarding the restrictions on use of material.

• Condition 6 regarding the capacity requirements

of clean and dirty water systems as well as the

containment to prevent spillage between the systems

more than once in 50 years.

• Condition 7 regarding the protection of water

resorces throgh polltion prevention measres

that deals with the collection, containment and rese/

evaporate/treat/dispose of water containing waste;

water and waste management; minimizing water

contact with mining activities or infrastrctre; damstability; erosion control; recycling of process water

and the prevention of process spillages; maintenance

of water systems; disposal of waste and wastewater.

• Condition 8 regarding security and additional

measres.

• Condition 9 regarding temporary or permanent

cessation of activities.

33 dWAF Wat Managmnt

sr - MnmmRqrmnt

The Waste Management Series prodced by DWAF

(second edition pblished in 1998 and sbseqently

being revised) indicate DWAF’s requirements in terms

of the management of waste and consists of a series of

docments, namely:

• Minimum Requirements for the Handling, Classication

and Disposal of Hazardos Waste.

• Minimum Requirements for Waste Disposal by Landll(revised in 2005).

• Minimum Requirements for Monitoring at Waste

Management Facilities (revised in 2005).

• Minimum Requirements for Waste Management

Training (envisaged).

• Minimum Requirements for Upgrading Waste Disposal

Operations (envisaged).

• Minimum Requirements for Waste Management

Facility Aditing (envisaged).

34 bt Practc Gn

r

A mine and therefore a hydrometallrgical processing

plant associated with a mine are reqired to implement

the principles of IWWM throghot its life cycle.

There is no legal or reglatory obligation for a mine or

hydrometallrgical processing plant to se the procedres

and gidelines provided in this BPG docment as crrently

the only legally reqired docments associated with

IWWM is the Environmental Management Plan (EMP)

and Water use Licences/athorisations Applications

(WuLA). The procedres and gidelines presented in

this BPG need to be incorporated into the EMP and willassist in implementing IWWM. The docmentation of the

IWWM principles into an IWWM plan can be sed as

motivation dring the WuLA. Practical motivation for sch

a plan is clear as access to sch a docmented IWWM

plan will greatly assist the mine and hydrometallrgical

processing plant in meeting its obligations in terms of the

varios environmental laws and reglations that affect

water and waste management over the fll life-cycle of

the mine.

Frther, if a mine and hydrometallrgical processing plantadhere to this BPG and others in this series as well as

the principles of IWWM they will be considered to have

met the DWAF reqirements in terms of sorce directed

reglatory measres.




____________________________________________________________________________________________________________________________________

10

4

CONsideRATiONs

WiThiN The MiNe

liFe-CyCle

Water management is aimed at ensuring the effective use of South Africa’s scarce water

resorces and therefore assists with water conservation and the protection of the water

resorces in general. The stepwise process depicted in Figre 2.1 allows for review at each

stage/step. In addition, fully dening the problem and gathering the required data in the initialstages ensres that ftre decisions are based on complete information. Figre 4.1 below sets

ot the ey points to consider dring each of the life-cycle phases.

Fgr 41: Conraton n t mn f-cc




____________________________________________________________________________________________________________________________________

11

41 exporaton, propctng,

pannng, fat an

gn pa

Cano-Riz and Mc Rae (1999) indicated that inclding

environmental considerations in the problem framing

exercise increases the nmber of constraints on the

design process. Generating process design alternatives

may inclde the application of existing design concepts

or the generation of new ones from rst principles. Time

available dring design, limits the nmber of alternatives

that can be generated and considered as well as

the level of detail to which these alternatives can be

analysed (trade-off between comprehensiveness and

economy). Engineering analysis sally begins with

evalation of mass and energy balances for each of

the candidate process ow sheets and these are then

used to determine ow rates, compositions, pressure,

temperatre, and physical state of all material streams,

as well as the energy consmption rates from varios

sorces. Analysis evalates the design alternatives

against a predetermined set of performance indicators

(economic and environmental impacts) or objectives.

The design process is an iterative process gided by

opportnities for improvement. The athors propose that

frther incorporation of integration principles will reveal

opportnities to decrease raw material consmption,

realising increased cost savings. Refer to this and

other references (Chapter 12) for frther reading on the

importance of design.

Figre 4.2 below indicates all the aspects and constraints

that need to be considered dring design. External

constraints to consider dring the design inclde:

• Resources

• Safety regulations

• Economic controls• Socio-political considerations

• Government controls

• Environmental regulations

• Standards and codes

• Physical laws

Fgr 42: Proc gn contrant (Marr, 2003)




____________________________________________________________________________________________________________________________________

12

Internal constraints to consider dring the design

inclde:

• Process conditions

• Level of control

• Choice of process

• Methods

• Time

• Personnel

• Environmental performance

• Materials

• Cost: 85% of the life cycle cost, nancial and

environmental, are determined by decisions made in

the planning and design phases (Marr, 2003) and the

importance of this phase can therefore not be over-

emphasised. The early stages of the design process

offer the greatest exibility in selecting the process

rotes for a facility and decisions made dring this

stage are therefore critical and have major impacts

on ftre phases. A frther estimated 50% of capital

expenditre on new plants is associated with isses

pertaining to environmental management (Marr,

2003).

• Life Cycle Assessment (LCA): Address all material

and energy transformations over “cradle to grave”.

This means emissions and the consmption of

resources at every stage in a product’s life cycle,

from its cradle (raw material extractions, energy

acqisition) to its grave (se and waste disposal)

needs to be considered. An inventoried listing of

environmental technologies, treatment processes,

and toxic chemicals sed, shold be made p front.

• Environmental Impact Assessments (EIA):

Generally, at the stage at when the EIA is condcted,

it is not easy to incorporate EIA information in the

design process in order to redce the environmental

impact of hydrometallrgical processing facilities,

bt it is essential. It is therefore important to ensre

that EIA information is incorporated into the design

phase and that environmental and commnity

related impacts are considered. Some impacts to

be considered inclde acid mine drainage, metals in

the environment, toxic reagents inclding cyanide,

sedimentation and water se, waste, emissions.

• Environmental impact considerations: Review

and tae accont of the environmental impacts of

exploration, infrastrctre development, mining or

processing activities, and condct the planning,

design and development of all facilities in a manner

that optimises the economic se of resorces while

redcing adverse environmental impacts to acceptable

levels. It is widely recognised that early consideration

of environmental matters dring the design is needed

to obtain good environmental performance at lowest

cost (set environmental concerns as constraints

on economic optimisation). The early stages of

conceptal process design which are generally

rather exible provide the greatest opportunities for

identication of potential environmental impacts and

to tae remedial action.

• Risk assessment and management: Employ ris

management strategies in planning and design,

operation and decommissioning, inclding the handling

and disposal of hazardos materials and waste. If a

preliminary ris assessment indicates nacceptable

riss for hman health or the environment, the lac of full scientic certainty should not be used as a reason

to delay the introdction of cost-effective measres

to redce environmental and hman health riss

to acceptable levels. An example of a detailed ris

assessment process sed and implemented dring

the project design phase is shown in Appendix C.

• Efciency and optimisation: Plan, develop

and design facilities and processes taing into

consideration the efcient use of energy, water and

other natral resorces and materials, inclding their

recycling and rese, the minimization of waste and

the responsible management of residal materials.

• Feasibility studies: undertae detailed planning and

feasibility stdies on the overall water balance, site/

plant layot, infrastrctre development and operation

in consltation with design and process engineers.

• Technologies: Consider and evalate different

hydrometallrgical process technologies and designs

in order to optimise the overall water balance, rese/

reclamation and water management.

• Inputs: Identify possible water sorces (water service

providers, local and srronding catchments, captred

rainwater, or water imported with raw materials)and undertake nancial assessment of water cost.

Review the intae of other resorces (energy etc) and

raw materials. Determine water qantity and qality

reqirements based on process design.

• Outputs: Aim to minimise emission of contaminants

of concern, mass of waste generated, contribtion

to specic environmental problems, and overall

environmental impact.

• IWWMP: Compile and inclde above into an Integrated

Water and Waste Management Plan.




____________________________________________________________________________________________________________________________________

13

42 Commonng an

opratona pa

• Implementation: Implement designs and processes

based on reslts of planning, design and feasibility

phase.

• Health and safety measures: Apply control

measres to ensre the contined health and safety

of all worers on as well as visitors to the site.

• Pollution prevention: Optimise polltion prevention

and redction/minimisation at sorce. Experience has

shown that any IWWM plan is more easily and cost

effectively applied if polltion prevention strategies

were optimally applied rst. It is therefore considered

advisable to rst investigate, develop and implementappropriate polltion prevention strategies wherever

possible, e.g. early recognition of the potential

for spillages and the adoption of appropriate ris

management strategies.

• General: Apply general “good” hoseeeping and

operating practices.

• Technologies: Continosly evalate process

technologies and facilities in terms of their

water reqirements and se. Consider whether

modications, improvements or new technologies can

be applied to redce these water reqirements and

ses.

• Environmental Management System (EMS):

Implement an EMS to ensre more effective control

and redce environmental impacts and shold

inclde organizational procedres, responsibilities,

processes, implementation strategies, measrement

and evaluation criteria, efciency measures, staff

training and goals for improvement.

• Review: Continosly review and improve water

management. Review and revise IWWM plan annally

based on performance assessments and changes in

the system.

• Monitoring: Implement monitoring system to

verify performance. Perform reglar maintenance,

refrbishment, inspections and performance

assessments. Environmental adits at reglar

intervals shold also be implemented and inclde

a thorogh investigation of every indstrial system

and process. Refer to BPG G3: Water Monitoring

Systems.

• Database: Store and manage information collected

in a database. The database shold show baseline

conditions as well as allow assessments of data to

determine when changes in conditions occr.

• Water and salt balance: Refer to BPG G2: Water

and Salt Balances.

43 dcommonng, cor

an pot-cor pa

• Residual impacts: Verify latent/residal impacts

throgh monitoring systems, performance

assessments and predictive modelling.

• Water management: Dene post-closure water

management options and determine best practicable

environmental option, e.g. treatment and discharge,

irrigation, sstainable development projects, etc.

• Finances and contracts: Finalise nancial and

contractal arrangements/agreements for post-closre

water management and maintenance of infrastrctre

with ftre landowners and/or responsible parties

and/or water sers.




____________________________________________________________________________________________________________________________________

14

51 Watr, a k n at (stp 1)

De to the limited water resorces available in Soth Africa, the competition for this valable

resorce is continosly increasing. DWAF as cstodian of the natral water resorces is

responsible for the allocation and management of the demand on the water resorces as well

as the protection of these water resorces against nacceptable qality deterioration. Globally

5

FiNANCiAl

CONsideRATiONs

(sTePs 1 ANd 2)




____________________________________________________________________________________________________________________________________

15

and nationally, the trend has been to prioritise water for

hman se (domestic se), food prodction (agricltral

se) and aqatic ecosystems (ecological fnctioning)

ahead of indstry sch as mining. This trend is evident

in South Africa and reected in our legislation and

reglations (NWA, reserve determinations).

With attitdes changing, water is increasingly seen as

a valable resorce. Increasing water demands have

reslted in a higher proportion of water being recycled

internally in indstries as well as the se of relatively

impure make-up water such as treated efuents rather

than potable water spplies. The impact of process

water qality has therefore also become an important

consideration.

It has therefore become important for the mining and

hydrometallrgical processing indstry to:

• not take water for granted as it is a limited, scarce and

valable commodity in Soth Africa that needs to be

conserved;

• follow a pro-active approach in terms of water

management whereby measres are implemented to

prevent impacts rather than mitigating impacts after

occrrence;

• incorporate water issues into strategic business

decision-maing to ensre sstainable se and

development of the indstry;

• ensure all current and future water users are not

adversely affected by the metallrgical activities as

water is a shared commnity resorce and other

users’ interest and rights need to be respected;

• reduce operating cost over the long term due to

efcient water use through water conservation; and

• optimise reuse and reclamation (refer to BPG H3:

Water Reuse and Reclamation); and

• realise water is a key business asset with social,cltral, environmental and economic vale.

Mines and hydrometallrgical processing plants shold

therefore identify opportnities and minimise ris in

terms of their water management plan. Responsible

water management will improve the public’s view of the

industry, the holding company and the specic operation.

Water management is now more often scrtinised by

external parties in applications for fnding and legal

athorisations. It has therefore also become important to

incorporate water ris into ey bsiness decisions.

52 Tr va an cot of watr

(stp 2)

In Soth Africa, water remains relatively cheap and

is therefore seldom broght into the prodction cost

eqation. The marginal economic advantage of effective

water management therefore requires it to be inuenced

by other factors sch as social pressres, coercion

from athorities, compliance with legislation or intent to

operate in an environmentally responsible manner. Water

management can accont for p to 15% of the cost of

hydrometallrgical processing (Wates and Van Nieer,

1991) and it depends on water use efciencies (wastage

and losses) and the relative density of process plps. As

the relative density of the process plp decreases, the

water volme in circlation increases, which reqires

an increase in transport and storage capacity, casing

increases in costs. Prodct lost in the water sed for

transport shold also be considered as a cost factor.

Water costs money and in order to save money

an operation needs to redce water sage (water

conservation), recycle more water (refer to BPG H3:

Water Reuse and Reclamation) and eep sed water

as clean as possible (polltion prevention) for rese and

ltimate disposal.

The tre cost of water incldes all direct and indirectcosts associated with water and incldes:

• Exploration, prospecting and planning cost –

inclding:

- grondwater extraction in exploration area;

- water sed by exploration/prospecting opera-

tions and worforce;

- conceptal and detailed designs;

- environmental impact assessments;

- feasibility stdies;

- ris assessments;

- constrction;- engineering wors;

- capital otlay etc.

• Water supply cost – inclding:

- obtaining water from a water service provider

(raw water charges);

- establishing connections to the main water

spply line;

- abstracting water from boreholes or srface

water bodies;

- competing industries’ demand for same




____________________________________________________________________________________________________________________________________

16

resorce;

- trading of water se entitlements in a water

scarce catchment;

- excess or shortage of spply etc.

• Social and cultural cost – inclding:

- perception by society and srronding water

sers;

- responsible water management to improve

pblic view;

- responsible care;

- ensring water availability to other sers as

reqired;

- water sed by indstry and therefore lost to

srronding commnities and downstream

sers;

- responsibility to commnity etc.

• Environmental and ecological cost – inclding:

- water sed and discharged thereby affecting

the natral srronding environment inclding

aqatic ecosystems;

- limited resorces and regional water shortages;

- environmental responsibilities;

- move the focs from site bondary conditions to

catchment level impacts (broader focs);

- conseqences of releasing materials to

srronding ecosystems etc.

• Economic feasibility cost – feasibility of the

operation considering all expenses and incomes.

• Waste management cost – inclding:

- the handling, transport, treatment and disposal of

all solid waste resides as well as wastewater;

- waste discharge charges (refer to waste

discharge charge system);

- discharge/disposal cost based on volmes/

qantities;

- contaminants load and receiving environment

etc.

• Operational cost – inclding:

- water spply;

- eqipment;

- reticlation/pmping;

- maintenance and refrbishment;

- labor/personnel;

- power consmption;

- waste management;

- engineering and infrastrctre;

- clean and dirty water separation etc.

• Water reticulation costs – inclding:

- pmps;- pipelines;

- energy/power consmption;

- pmping for transport;

- storage facilities with reqired capacity;

- water losses and wastage etc.

• Water treatment cost – inclding:

- the treatment of water to improve qality for se

or to allow for rese in the process;

- treatment for se by another indstry;

- treatment for discharge prposes etc.

• Maintenance cost – inclding:

- maintaining water infrastrctre sch as storage

facilities, pipelines and pmps as well as

monitoring equipment such as ow meters;

- maintenance of water infrastrctre de to

corrosion/scaling etc.

• Labour/personnel cost – inclding:

- personnel responsible for monitoring water se,

sampling water, managing water, information

captring, doing assessments and reporting,

maintenance;

- training and sills development;

- jobs;

- interaction and relationships with staeholders;

- allocation of dedicated hman resorces;

- spport fnctions etc.

• Remediation cost – inclding:

- mitigation and remediation of spillages dring

operation;

- remediation and rehabilitation of site after

decommissioning and closre etc.

• Legal cost – inclding:

- acqisition of necessary licenses and

athorizations;

- nes for breaches of regulations;

- reglatory demands etc.

• Risk cost – inclding:

- technical ris (ris of sing a “poorer” water

qality verss the saving in water prchasing

cost);

- environmental ris that may lead to liabilities;

- maret price changes etc.




____________________________________________________________________________________________________________________________________

17

The tre vale of water incorporates perceptions of

water by external parties and the vale for the contined

operation of the bsiness, for example:

• Cultural or spiritual associations with water or the land

on which water infrastrctre is planned;

• The value of ecosystem services reliant on the same

water spply;

• Competing social demands on the same resource

(e.g. domestic water spply or recreational se);

• Social, cultural, environmental or economic impact on

downstream water sers if water qality is affected by

operations or not available to other water sers;

• Impact on reputation for perceived poor water

management performance;• Cost to the operation if water excess or wastewater

cannot be discharged;

• Economic value to allow production and processing to

tae place; and

• Loss of income, jobs or market share if there are

prodction ct-bacs as a reslt of water excess or

shortage.

A strategic water management approach shold ths

ensure that water is more efciently managed and valued

as a vital bsiness and commnity asset.

The rese of process water in hydrometallrgical

processing plants is often desirable not only for

environmental protection reasons bt also for the cost

saving associated with it. Cost savings are seen in

terms of redcing the qantity of external water to be

prchased and consmed, simplifying operations, saving

in infrastrctre cost by redcing the transportation

infrastrctre reqirements (piping) etc.

In terms of nancial considerations, it is also important

to realize the benets industry often brings to an area or

commnity which may inclde:

• The establishment of water supply infrastructure and

water spply to commnities in the area;

• Social benet in terms of job creation, infrastructure

and services establishment, improvement of qality

of life; and

• Economic benet in terms of nancial investments

made in the region and contry.




____________________________________________________________________________________________________________________________________

18

61 st an proc knowg (stp 3)

Only isses nown and nderstood can be managed. To apply “good” hoseeeping practices

and operating procedres (Step 6), it is therefore essential to have a good nowledge and

nderstanding of the plant. knowledge and nderstanding abot the following items are

reqired:

• Site: General site and plant layot; site locality in proximity to power/electricity spply,

water supply, roads, rail and other support infrastructure has obvious benets; site

location in relation to water resorces is important in terms of impacts on water resorces;

nderlying geology of the site in terms of possible grondwater impacts; site limitations

sch as bondary, possible expansions, topographical gradients, soil conditions; site water

management plans; site location in terms of locality of ore body (mine) will affect transport

cost etc.

6

iNFORMATiON

GATheRiNG

(sTePs 3, 4 ANd 5)




____________________________________________________________________________________________________________________________________

19

• Environment/catchment: Geology of the area;

grondwater/aqifer characteristics; boreholes and

springs; geohydrology; topography of the area; climate

(precipitation, evaporation etc); biogeochemical

cycles; dams and water corses; hydrology; wetlands;

water sers; srronding land ses; sensitivity

of receiving and srronding environment; water

qantity and qality (grondwater and srface water);

contaminants of concern in terms of the environment;

variability of environmental conditions (droght,

seasonality etc); reserve determination (obtain from

DWAF) and water qality objectives; catchment

management agency etc.

• Process: Process ow diagram; piping and

instrmentation diagrams; process featres

(pH, oxidation-redction conditions); process

methodologies; process exibility (expansion);

eqipment and infrastrctre; power/electricity

reqirements for the process; inpts and otpts;

contaminants of concern in terms of the process

technology sed; process sensitivity to variability and

changes; technology design and operation; type and

scale of operations; steps inclding ore preparation,

concentration of metal minerals, solbilising metals,

prifying soltions throgh removal of imprities,

recovery of metals from soltion (oxide ores arefor example not well known for their oatation

characteristics and are ths treated as whole ores

in hydrometallrgical facilities by heap, vat or high-

pressre acid leach, or redctive pyrometallrgical

processes whereas slphide ores can be treated in

concentrators to separate a concentrate, from the

tailings material, which cold be frther processed in

a roaster or smelter followed by a hydrometallrgical

facility, or directly by a hydrometallrgical facility).

• Raw material/ore: Type of roc/ore being mined and

processed (slphide/oxide); characteristics of the

mined material (geochemistry); mineral ore grade;

variability and non-homogeneity of ores in terms of

metal content; mineralogy; imprities present in the

ore body; complexity and variability (qantity and

qality) of the feed.

• Other inputs: Characteristics of other materials/

chemicals sed in the process; concentrations of

elements; form of elements (speciation).

• Water resources: Be pro-active in investigating

potential water spply sorces; consider grond- and

srface water resorces; excess or scarcity of water;

sstainability of resorces; sensitivity of receiving

water resorces; water qantity and qality as well as

its variability (seasonality); contaminants of concern;

assess impacts of water spply sorces on process/

plant performance.

• Other resources: Allocation of dedicated resorces;

personnel and teams; training and sills development;

infrastructure (equipment); nances (funding);

accontabilities; responsibilities; time investment;

management commitment and spport.

• Mine/plant water users: Process water qantity and

quality requirements (sulphide ore otation has strict

requirements in terms of the water phase’s chemical

composition de to wet oxidation); laboratory/pilotstdies to investigate impact of water spply on mine/

plant water sers; process sensitivity to qantity and

qality as well as variability; contaminants of concern;

possibility of water rese and reclamation in or

between processes (refer to BPG H3: Water Reuse

and Reclamation); water treatment reqired to mae

water t for use (refer to BPG H4: Water Treatment ).

Also see Section 6.3 below.

• Waste: Solid, liqid and gaseos waste generated

on site; handling and management of waste; waste

transport; waste treatment to redce volme,

hazardosness or impact; disposal/discharge of

waste.

• Water reticulation: Reticlation systems; limitations;

different and separate circits; closed circits; storm

water management and incorporation of contaminated

storm water into water circits (refer to BPG G1:

Storm Water Management ); management of process

water and spillages; prevention of losses from system

(maintenance and inspection); inpts to the system

(precipitation, spply water, grond- and srface

water abstraction, recycled water); otpts from the

system (evaporation, rnoff, seepage, reglatedand nreglated discharges, losses); storage in the

system.

• Monitoring: Water measring and monitoring;

monitor all inpts and otpts; assessment of impacts

on grond- and srface water resorces de to

operation; polltion plmes; water and salt balances

(refer to BPG G2: Water and Salt Balances).

• Future: Ftre plans; changes in technology (cleaner

technology – Step 9); expansions; research and

development.




____________________________________________________________________________________________________________________________________

20

62 Watr an at/oa aanc

(bPG G2: Watr an at

aanc) (stp 4)

BPG G2: Water and Salt Balances deals with the design,

compilation, implementation and management of water

and salt balances in detail and the details will therefore

not be repeated here. The following are however, worth

noting in this docment:

• Objectives: Clear objectives shold be stated for the

water and salt balance; the objectives shold consider

the crrent as well as possible ftre scenarios in the

plant (plant life-cycle).

• Divisions: The water and salt balance for a large

complex operation shold be divided into smaller management nits; the same formats and procedres

shold be employed for each management nit to

allow the exchange of information over management

nits; establish bondaries for individal balances;

differentiate between different water circits.

• Updates: The water and salt balance shold be

pdated reglarly to inclde process changes,

new information, expansions, new data lined with

monitoring (refer to BPG G3: Water Monitoring

Systems Systems), management measres

implemented etc; pdates shold be an iterative

process in order to obtain higher levels of accracyand for renement; the water and salt balance should

be exible to allow for and accommodate changes.

• Loads: Conservative salts shold be sed to

constrct overall water and salt balances; polltants

or contaminants of concern can be sed to determine

polltion loads;

• Calculation of unknowns: unnowns can be

calclated throgh the simltaneos soltion

of eqations; develop sch eqations; address

imbalances.

• Hydrological cycle: Consider seasonal changes;

wet and dry seasons; precipitation; evaporation; rn-off; percolation/inltration to groundwater aquifer;

seepage etc.

• Output: Level of detail is based on objective; validation

of reslts/otpt; manal calclations; spreadsheet

based balance; PC-based software; high-end

engineering software; compterized system.

Water and salt balances are important water management

tools to be sed to provide gidance in terms of

management actions reqired, areas to focs on in terms

of polltion load, major water consmers, etc.

63 Mn/pant watr r

(stp 5) As part of the site and process information gathering,

nowledge shold have been obtained in terms of the

water sorces available. It is eqally important to obtain

information on the mine or process plant water sers in

terms of:

• Water quantity requirements - Major water consmers.

• Water quality requirements – Is potable qality water

required or can efuent from another user/processpossibly be sed? Consider that some mine/plant

water sers may be sensitive to certain constitentsin the water and these constitents may in certain

instances have a negative effect on the specic mine/

plant water ser or its process performance (seecontaminants of concern).

• Sensitivity to quantity and quality changes as

well as variability – Spply water may change in

qality over time, for example if water is continosly

recycled, some constitents (sch as TDS or salinity)may increase in concentration (accmlation) with

each cycle (de to evaporation and sbseqent

concentration of dissolved salts) and may thereforealter the chemistry of the system. Eqalization or

stabilization ponds (tans/dams) may be reqired

to ensre less variability to the ser sensitive tochanges.

• Contaminants of concern – These are contaminantsor constitents in the water that may affect/impact

process performance.

• Pollution loads – Constitents fond in water at

higher concentration than expected. The sorce

of the additional concentration of the constitent/contaminants is a direct reslt of an activity sch as

processing. Contaminants are also added to water as

it is sed and recycled.

• Water reuse and reclamation – Examine the

possibility of water rese and reclamation in or between processes. Refer to BPG H3: Water Reuse

and Reclamation. Consider the time-lag between

water being reqired and water being available dringdifferent phases of the mine (for example, processing

which reqires large qantities of water starts mchlater than dewatering for bl sampling and access

to the ore body which generates large qantities of

water).

• Water treatment – Establish water treatment reqire-

ments (softening, etc to redce corrosion/scalingpotential). Refer to BPG H4: Water Treatment .




____________________________________________________________________________________________________________________________________

21

Water is nown as the niversal solvent since it has the ability to dissolve, to some degree, every

substance in the earth’s crust and atmosphere. Water is therefore also the main medium for

transportation of pollutants/contaminants within the connes of a mining or hydrometallurgical

processing operation and from these operations to the otside environment. Water dissolves

gasses from the air (SO2gas dissolves in rain water to yield acid rain); minerals from the earth’s

crst (slphide in pyrite dissolves in water nder aerobic conditions to yield slphric acid

soltions); and it pics p sspended matter from the earth and air (soil particles are carried in

rnoff dring erosion and when water is applied for dst control). Ths, the more water there is

to manage, the more difcult the control of pollutant/contaminant migration becomes.

71 Mnmz watr /watr conrvaton

It is important to minimize the amont of water sed in a hydrometallrgical processing

operation. The areas of high water consumption should be targeted rst in terms of water

minimization strategies. Water and wastewater minimization has been driven by the rising

7

hOuseKeePiNG

ANd WATeR

MANAGeMeNT

sysTeMs (sTeP 6)




____________________________________________________________________________________________________________________________________

22

cost of raw/potable water from service providers and

efuent treatment or discharge charges as well as

more stringent environmental legislation. Also refer to

water pinch techniqes and analyses as described inreferences (Section 12) and BPG H3: Water Reuse and

Reclamation. Generally, hydrometallrgical processing

involves the se of water for the initial processing of the

mined ore and incldes amongst others the following

fnctions/applications:

• Dust control: Control of wind-borne particles and

prevention of polltion. Reqired on roads becase

of vehicle movement; reqired on waste dmps de

to drying of material; reqired in wet scrbbers to

prevent dst release into atmosphere.

• Water-based hydraulic mechanical equipment: Water affects the hydraulic uid characteristics in

terms of emlsion stability, lbricity, corrosivity and

erosive tendencies.

• Reticulation/transport: Transport of tailings material

to a thickener/clarier or residue disposal facility

for wet deposition; water is often seen as an inert

transport medim; transport of wet ore after washing

and wet separation processes.

• Cooling and heating: Chilled water circit; condenser

cooling system; evaporative cooling especially dring

exothermic reactions; steam generation; boilers.

• Processing and reaction medium: Ore preparation

sch as washing of mined material and milling and

grinding processes. Concentration processes sch

as separation circuits; magnetic separation; otation;

hydrocyclones; screens; lters; classiers; thickeners;

precipitation. Solbilisation processes sch as

leaching. Prifying processes to remove imprities

such as electro-winning, precipitation, otation and

solvent extraction.

• Plant cleaning: Spraying of water for cleaning of

spillages

In terms of the above ses, it is important to eep water reticlation circits separate from each other and closed

in certain instances to prevent cross-contamination. For

example, the water transporting the milled ore might

be considered ncontaminated in terms of chemical

composition if the water was ncontaminated to start off

with and not mixed with water from another area in the

process (ths a closed circit) since no chemicals are

generally added neither do any major chemical reactions

tae place dring the initial milling process of mined

material. The sspended material in the water (physical

composition of water) is easily removed in a thicener

or clarier through precipitation or via some lter or

screen. Wet processes shold also be replaced with dry

process technologies where possible to redce water

consmption.

72 Watr grgaton

Water containing waste (contaminated water) shold

be classied and separated based on the level of

contamination and possible ses. Very often at

hydrometallrgical processing plants, storm water that

is not highly contaminated is combined with process

spillages within water storage or management facilities

(refer to BPG G1: Storm Water Management ). This

limits the rese possibility of a large volme of water that

was only moderately contaminated (contaminated stormwater) as it has become more contaminated de to the

addition of process spillages. Implementing segregation

of wastewater and mltiple storage or management

facilities will ensure the more efcient reuse of water

on the site. Less contaminated water recovered

will have nmeros rese possibilities when not mixed

with highly contaminated process spillages (refer to

BPG H3: Water Reuse and Reclamation). The

separation of water based on level of contamination

will also redce the qantities of highly contaminated

water eventally reqiring treatment before rese or

discharge.

73 storag of matra

Avoid cross-contamination by storing all materials,

chemicals, prodcts etc separately.

• Site layout and positioning: Storage areas shold

also be organized and planned in sch a manner

within the general site layot to allow easy access

from the area reqiring the particlar material and

avoiding the crossing or bypassing of other different

storage areas in an attempt to reach the reqired

material.• Reactive chemicals: Reactive chemicals (chemicals

sch as lime that readily dissolve in water or

chemicals that can react with water) shold be stored

in closed areas to prevent water (rain or rnoff) from

contacting them. This storage may inclde silos

(powder chemicals), closed tans (soltions), sealed

drms (oils), closed hoppers (to allow direct addition

to process) or sealed bags on pellets within a bilding

with a roof and concrete oor (granular chemicals).

Where a process spillage ris exists, appropriate

bnding strctres shold be constrcted.




____________________________________________________________________________________________________________________________________

23

• Unreactive materials: unreactive materials

(materials that will not readily dissolve in water or

react with water) sch as mined ore or dried milled

ore might be stored in mch simpler strctres. Thesestructures’ main objective would be to prevent material

from washing away and losses (rnoff control). This

storage may inclde anything from an open stocpile

to a stocpile area with concrete bondaries and a

roof.

74 hg contamnaton rk

ara

Some areas may present a high contamination ris and

therefore reqire special measres to be pt in placeto prevent any of the contents from reaching any area

otside the location. This may inclde acid storage

areas and specic plant areas. To prevent contaminants/

chemicals from sch areas reaching the otside

environment, it is recommended that the area of location

be bnded and sealed with a concrete base (acid brics

or other approved prodcts may also be sed for this

prpose). The concrete base will prevent any spillage

from inltrating and contaminating the underlying soil

and grondwater aqifer. The bunding will prevent any

spillage from reaching srface areas located otside the

bnd and contaminating srface rnoff. The bnding

shold be designed according to approved gidelines

to contain 110% of the capacity of the tan or reactor it

contains. To ensre proper spillage clean-p and control,

the following is reqired:

• Bunded area’s base should be sloped to allow

drainage to a low point within the bnd. A smp will

be located at this point.

• The sump will be eqipped with a sitable pmp

which will be level activated. This means that as soon

as the liqid in the smp reaches a certain level the

pmp will atomatically be switched on and start

pmping.• The pump (sitable to pmp the particlar liqid) will

pmp all liqid ot of the smp at a set rate into the

tan or reactor from which the spillage occrred.

• This system ensures the management of a spillage

within the area where it occrs and therefore

recirculates spillages bac to their origin, eeping

the system closed.

• In emergency or extreme events (sch as the

rptring of a tan/reactor dring a 1:50 year storm

event), where the bnd with smp-and-pmp system

cannot handle the spillage, a second pmping system

may be reqired.

• The second pumping system will only be activatednder sch emergency or extreme conditions and

pmp the excess liqid to an emergency spillage

control dam/tank .

75 storm watr managmnt

(bPG G1: storm watr

managmnt)

Storm water management is dealt with in BPG G1:

Storm Water Management and the details will therefore

not be repeated here. The following points are however worth noting in this docment:

• Hydrological cycle: Impacts of the hydrological cycle

(seasonal variation) on an operation/process and vice

versa; dealing with oods (emergency or extreme

events); dealing with srface water rnoff in a plant;

sstainability of a storm water management plan over

different hydrological cycles and different phases

of the plant (the plant life cycle: design, operation,

closre, decommissioning and post-closre).

• Clean and dirty catchments: Division of an area

into dirty and clean areas or catchments and eepingwater from one separate from water from the other; no

lin between clean and dirty circits/areas to prevent

cross-contamination.

• Clean areas and clean water: keep clean areas

clean; eep clean storm water clean by diverting this

rnoff arond possible polltion sorces to prevent

contact with these polltion sorces thereby preventing

contamination of clean storm water (constrct

diversion berms); maximize extent of clean areas

and the amont of clean rnoff (roofs on bildings

with possible contamination sorces will prevent

rain inltration to the area and therefore contact with

polltion sorces, reslting in clean rnoff from the

roofed area); direct/rote clean storm water towards

water resorces for replenishment (grondwater

aqifer and srface water bodies); clean storm water

only reqires containment when the volme poses a

ris (attenate in retention ponds and control release

to prevent soil erosion, damage of stream bans and

bildings or life loss); incorporate very small clean

area into larger dirty area considering site layot

limitations.




____________________________________________________________________________________________________________________________________

24

• Dirty areas and contaminated water: Minimize

dirty or contaminated areas; captre and contain

contaminated storm water from dirty areas for

rese; consider any rnoff that has been in contact

with pollution sources as contaminated and unt for

discharge into the receiving environment; prevent

seepage of contaminated; prevent overows of

contaminated water from storage facilities; manage

captred and contained contaminated water

according to the DWAF hierarchy for water qality

management (see preface); moderately pollted

water (sch as contaminated storm water) shold not

be frther pollted by mixing it with process spillages

(see Section 7.4).

76 Canng

Clean-p practices are important and the following

shold be considered:

• Clean immediately: All spillages shold be cleaned

as soon as they occr and before these spread and

contaminate other areas or materials.

• Report spillages: All spillages shold be reported to

the appropriate cleaning team immediately for action.

• Water for cleaning: The cleaning of spillages with

water (oor washing) should be prevented wherepossible. Cleaning of spillages with water shold be

limited to spillages of water soltions or water-solble

liqids. Preferably se process water or dirty storm

water for cleaning prposes (also see reincorporation

of spillages below). Spillages of solids (powders,

granlates etc) shold be physically/mechanically

piced p (sweeping, dry scing, scooping etc) and

not merely be washed with water (hosing) into storm

water drains.

• Reduce cleaning water quantity: Redce water

sed for cleaning by pipe restrictions in hoses (smaller

diameter pipes), sing spray jets (cover larger srfacearea), sing mops rather than hoses.

• Reincorporation of spillages: Where possible,

spillages shold be re-incorporated into the

circit from which the spillage occrred to prevent

nnecessary losses. This is obviosly provided that

the spilled material has not been contaminated by

another sorce since this may impact prodct qality

at the end.

• A waste: Spillages that cannot be resed or be re-

incorporated shold be considered to be waste.

• Hydrocarbon spillages: Hydrocarbon spillages

shold be handled in a separate system (oil/grease

traps) by an expert in this eld.

77 eqpmnt an mantnanc

The following is important:

• Alternative equipment: Eqipment sch as liqid

ring pmps can be replaced with mechanical sealed

pmps; once-throgh cooling systems can be

replaced with recirclating ones etc.

• Check for leakages: Check pipes, anges and ttings

reglarly to mae sre these are in good condition

and not leaing.

• Inspect condition: Chec piping, tans and valvesfor repair, refrbishment and corrosion.

• Pro-active maintenance: Implement a pro-active

maintenance programme in which eqipment is

reglarly checed/inspected, replaced/repaired

before water losses are experienced.

78 stanat

Water management systems incorporated dring

the design and constrction phases of an operation

can be tailor-made to the application. These water

management systems can then be designed at the start

to last throghot the different phases of the mine and

processing plant life cycle to ensre sstainability. With

an existing operation, the water management system

has to consider the existing system infrastrctre and

layot, ftre expansions etc.




____________________________________________________________________________________________________________________________________

25

8

WATeR QuAliTy

ANd CONsTiTueNTs

OF CONCeRN

(sTeP 7)

81 Mnmz gnraton of contamnant

811 Rvw ntak/npt/raw matra

Contaminants are sbstances or constitents fond in a medim sch as water at a concentration

higher than expected from other considerations sch as the natral environment, and where

the sorce of the additional concentration of the sbstance/constitent is as a direct reslt of

hman activity (sch as mining or processing).




____________________________________________________________________________________________________________________________________

26

To be a constitent of concern and pose an environmental

ris, the constitent mst have an inherent capacity or

potential to case harm or impact on another ser; the

constituent must be present in environmentally signicantqantities; the constitent mst be available for ptae or

absorption within the environment. Refer to Appendix A.

• Input optimization: Raw materials and reagents sed

as input to a hydrometallurgical plant’s processing

are costly and many inclde/contain hazardos

sbstances. It is therefore necessary to review the se

of these raw materials and consider the following:

- Reduce raw/potable water intake: Water

obtained from a water service provider (sch

as a mnicipality) or otside sorce is costly

and may constitute a signicant portion of themonthly operational cost on a hydrometallrgical

plant. Minimizing raw/potable water intae helps

towards water conservation. It is not always

essential to se water of a potable qality for all

applications/processes. Investigate sing water

of a lesser qality withot affecting process

performance or prodct yield. It is important

to now process water qality reqirements

as well as the composition of the inpt water.

(Example: se water stored ndergrond, refer

to BPG H3: Water Reuse and Reclamationand BPG: A6: Water Management for

Underground Mines)

- Eliminate/reduce auxiliary inputs: Consider

eliminating or redcing inpt materials sch

as chemicals/occulants added to the process.

Establish the minimm qantity of the chemicals

reqired or the minimm concentration of the

active ingredient reqired to yield the same

prodct qality and qantity withot redcing

process performance. Overdosing is costly. By

redcing the qantity of the chemical added, theqantity of any hazardos/harmfl sbstances

contained in it and added to the process is also

redced and fewer inherent by-prodcts reslt.

Frthermore, establish how critical the chemical

is for process performance and prodct

reqirements.

- Locality of input: It is possible that by adding

the chemical at a different point in the process,

its qantity reqired can be redced as its se

would be more efcient/effective.

- Alternative inputs: Consider replacing/

sbstitting some inpt materials with less

hazardos/harmfl materials. Determine which

other materials available on the maret also

contain the active ingredient reqired for the

process. Alternatives may be more cost-effective

and less hazardos withot compromising

process performance or prodct qality.

• Logistics: Improve control of the resorces in terms

of:

- Purchasing: Compare prices and sppliers

of resorces; logistics of placing orders and

ordering resorces from reliable sppliers;

tracking of resources’ supply; timeous delivery

of resorces on site by a reliable transport

company; payment of sppliers; monitor

resorces available to ensre timeos ordering;

plan for periods of short spply.

- Handling and storage: Deliver; proper storage

of materials to prevent losses (secre, prevent

wash-away); on-site transport (conveyor belts);

maintenance of storage or transport facilities

to prevent losses (roofs of bildings). Also see

Section 7 on hoseeeping.

- Addition/control during processing: Prevent

overdosing dring addition; mixing to improveeffectiveness and redce qantities reqired;

moving the point of addition in the process

to increase efciency and reduce quantities

reqired.

• Reuse and reclamation: Refer to BPG H3: Water

Reuse and Reclamation and Section 9. use

inpt materials that can be regenerated or resed;

materials with longer lives and rese possibilities;

recycling of sed oil/grease; rese of contaminated

water; regeneration of lters used in the process;

cleaning and maintenance to ensre contined

process performance and operation withot reqiringreplacement of eqipment.

• Energy optimization: Redce energy reqirements

as it is also a large monthly expense in any

hydrometallrgical plant; alternative process

technologies that reqire less energy; investigate

novel energy sources; ensure efcient energy use.

• External material/streams: Avoid contact with non-

process chemical and extraneos water streams

(such as off-site runoff nding its way onto the site,

also refer to storm water management in Section 7




____________________________________________________________________________________________________________________________________

27

and BPG G1: Storm Water Management ); prevent

external material/streams from entering the circit.

812 Optmz poton prvnton anrcton at orc

Mine-related/derived polltion is one of the major

cases of water qality degradation in many parts of

the world and potential sorces of polltion from a mine

or hydrometallurgical processing plant include efuent

discharges, leachate or rnoff from reside disposal

facilities, storm water and the intentional or accidental

release of process streams to srronding areas.

Each mineral has a set of niqe physical and chemical

properties, and therefore requires the use of specic

extraction and rening techniques. Environmentalcomplications therefore vary between sites principally

becase of the mineral targeted for extraction, the

geological setting in which the mineral occrs and the

se of different chemical reagents (see Section 8.1.1)

and processing techniqes (see Section 10).

The nderlying theory behind polltion prevention is

that it is economically more sensible to prevent wastes

rather than implement expensive treatment and control

technologies to ensre that waste generated does not

threaten hman health and the environment. Polltion

prevention, which lessens or eliminates waste generation,

is classied as source reduction. Source reduction is oneof the least expensive methods of waste minimization

and is often achievable with minor process changes or

simple improvements to hoseeeping techniqes.

Source control is dened as any activity that reduces or

eliminates polltion/contamination or the generation of

waste at the sorces throgh either practice or process

changes and may inclde:

• Product changes;

• Material or resource input changes (see Section

8.1.1);

• Technology changes (see Section 10 on cleaner

technology); and

• Implementation of good operating practices (see

Section 7 on hoseeeping).

Polltion minimization is mainly addressed in Section 7

in terms of hoseeeping and the following points are

reiterated here bt not discssed in detail again:

• Segregation of clean and dirty water including the

separation of process water and storm water as

well as the separation of clean storm water from

contaminated storm water.

• The capturing, containment, and reuse of process

water and contaminated storm water on the site.• Bunding, containment and recycling of water and

spillages in certain high ris areas to recirclate/rese

as close to sorce/origin as possible.

• Construct roofs over storage and process areas to

prevent water inltration and maximize clean runoff.

• Place concrete in storage and process areas to

prevent seepage into nderlying grondwater.

• Slope areas to minimize erosion and maximize runoff

volme and rate in order to minimize contact with

possible polltion sorces.

• Diversion of storm water around major pollutionsorces to minimize contact with polltion sorces

thereby increasing clean storm water available to

replenish water resorces.

82 Watr qat rqrmnt

for mn/pant watr r

Certain water qality related problems sch as scaling

(see Appendix A) may be experienced by certain mine/

plant water sers depending on the qality of the water

spplied. Water qality related problems are directly linedto the constitents of concern and it is therefore possible

to determine the constitents responsible for water

qality problems being experienced. Different mine/plant

water sers may experience different problems relating

to the same water qality and therefore each mine/plant

water ser has its own niqe water qality reqirements.

Since water qality reqirements are determined by site-

specic factors including locality, mining and processing

methods, and commodity mined, only general principles

and considerations are noted here.




____________________________________________________________________________________________________________________________________

28

For water to be resed within the mine or

hydrometallurgical processing plant, a clear denition of

the water qality reqirements of the mine/plant water

sers mst be prepared. This will consider constitentsthat may interfere with the performance of processes or

with prodct qality or yield.

It is important that the constitents of concern be

determined based on a reliable data record over an

extended period (refer to BPG G3: Water Monitoring

Systems) and with the appropriate statistical calclations

(minimm, maximm, 95th percentile etc) as well as

throgh consideration of the water qality related

problems experienced by the sers (see Appendix A).

The water qality objectives for the mine/plant water

sers will represent the worst possible water qality thatcan be tolerated bt that still eliminates/redces any

process or other problems experienced to an acceptable

level.

The concentration or qantities of prodct in wastewater

or process water depends on the efciency of the

process technology sed. Prodct losses also increase

with increasing water consmption and poor water

management therefore leads to poorer extraction

efciency. Consequences of poor management can also

inclde poor process water qality and the associated

corrosion and scaling, which ltimately again redce

process efciency. Recovery efciency and product

qality may sffer de to the presence of contaminants

in process water.

83 Montorng, mantnanc,

npcton an at

Monitoring: Reference is made to BPG G3: Water

Monitoring Systems which provides clear gidance on

why (objectives), how (procedres), what (parameters),

when (freqency) and where (location) to monitor. It

frther provides details from the design phase of amonitoring programme throgh the implementation

and data collection phases, throgh to reporting (data

management, maniplation, presentation and reporting

format) and aditing (internal/external review) phases.

Maintenance: All eqipment and machinery associated

with the hydrometallrgical plant shold be maintained

(e.g. cleaning of pipes to prevent scale bild-p) on a

reglar basis to prevent process failre or redced

process performance de to malfnction. If reglar

maintenance is not condcted, raw materials may be

wasted, processing time may be lost or prodcts may

be compromised. A maintenance schedle will ensre

that all eqipment and machinery are in pea woring

condition.

Inspections and audits: It is important to condct

inspections (internally) to ensre monitoring and

maintenance is condcted as planned and to ensre

appropriate action is taen based on the monitoring and

inspection otcomes. Internal and external adits will

also highlight problem areas that reqire management

actions.




____________________________________________________________________________________________________________________________________

29

9

WATeR

Reuse ANd

ReClAMATiON

(sTeP 8)

In order to maximize water rese and reclamation, it is important to minimize water qality

deterioration by preventing polltion. See previos sections (Sections 7 and 8).

The scarcity of water resorces available to the mining and hydrometallrgical processing

industry (due to the demand of other users) and the desire to reduce efuent discharges from

mining and hydrometallrgical processing operations are the main reasons for the rese and

reclamation of process water in the mining and hydrometallrgical processing indstry.




____________________________________________________________________________________________________________________________________

30

A separate BPG docment was prepared on water rese

and reclamation (refer to BPG H3: Water Reuse and

Reclamation) and the details are therefore not repeated

here. The following points are however worth noting inthis docment:

• Opportunities for water rese and reclamation:

- Areas where large volmes of water are sed or

disposed;

- Areas where good qality water is imported and

poor qality water is lost;

- Areas where good qality water is prchased/

abstracted while water of a poorer qality is

acceptable for se; and

- Areas where the implementation of polltionprevention measres/strategies do not reslt in

the elimination of polltion.

• Benets of water rese and reclamation:

- Cost saving de to redced raw water intae

from otside (abstraction from water resorces

or prchasing from water service provider),

more efcient use of valuable resources as

well as redced disposal and treatment cost for

wastewater;

- Legal compliance as waste minimization and

water conservation goals are met;- Limit liabilities by redcing and minimizing

release to and impacts on the srronding

receiving environment;

- Protect pblic health by preventing polltion of

the environment and water resorces;

- Protect the environment throgh polltion

prevention, especially the water resorces

(minimize water qality deterioration);

- Water conservation throgh redced intae and

consmption;

- Reclamation of materials that have a highreclamation vale and/or a severe impact on the

environment; and

- Improve pblic image de to concern shown for

the environment.

• Water sources: Identify and consider all possible or

alternative water sorces inclding boreholes from

which grondwater can be abstracted, streams/dams

from which water can be abstracted in the local or

neighboring catchment, captred rainwater, water

imported with the raw materials, other srronding

indstries with excess water and having to discharge

water, mine/plant process nits discharging water

(water/efuent generating processes), water service

providers (mnicipality etc). Implement all possible

measres to prevent/minimize the polltion of these

water sorces. Characterise the water sorces with

respect to ow rate (quantity), quality and variability

throgh a monitoring system (refer to BPG G3: Water

Monitoring Systems Systems). Aim to se water

sorces with minimm amont of treatment de to

the cost associated with water treatment (refer to

BPG H4: Water Treatment ). Ionic strength of water

source is important as it may inuence solubility of

other constitents present in process materials.

• Minimize water intake: Only prchase water (potable) from water service providers for processes

reqiring sch good water qality or additional water

reqirements that cannot be spplied in the system.

Only obtain water from otside sorces (environment

or other indstries) that cannot be spplied within the

system.

• Mine/plant water users: Establish clear and accrate

water quantity and quality requirements/criteria (t-

for-prpose) for all mine and process related water

sers. Establish water qality constitents affecting/

impacting on prodct qality or yield and/or process

performance and determine minimm acceptablestandard reqired from water spply. Mine/plant

water sers shold be provided with the poorest

possible water qality bt which does not case

signicant user, product quality or process related

problems (scaling etc). Compile water se inventory

- list of existing and potential mine/plant water sers

(indirect or direct). Grop mine/plant water sers with

similar water qality reqirements (in terms of ey

constitents) together to provide a nmber of different

water qality grops/ categories. Water sorces,

depending on the origin and contaminants, may have

a deleterios effect on certain hydro-metallrgicalprocesses and it is therefore essential to establish the

contaminants within the sorces that may impact on

or adversely affect the process.

• Minimize consumptive water use and losses:

Minimize evaporation from evaporative cooling

systems and clean water storage facilities. Limit

evaporative cooling systems (investigate air cooling).

Minimize seepage (throgh appropriate lining) and

overow (through sufcient capacity, GN 704) losses

from all water systems.




____________________________________________________________________________________________________________________________________

31

• Process technology: Investigate alternative process

technologies or modication/changes to existing

process technologies that cold be applied and that

se less water (see Section 10).

• Water reticulation systems: Optimally match mine/

plant water users with the identied water sources,

taing cognizance of economic and practical restraints

with regard to having different water reticlation

systems. Therefore, identify opportnities for resing

efuent water from one process as inuent water to

another process. Establish where water reticlation

networs and storage facilities may need to be

installed or extended/enlarged or modied. Align and

allocate recycled water qality and qantity to varios

mine/plant water sers. Achieve the minimm se of

raw water or optimal ow conguration in the particular

system of operations.

• Unused internal water sources: Categorize all

nsed internal water sorces (inside the mine or

hydrometallrgical processing operations) that have

not been allocated for reuse to a specic mine/plant

water ser based on one of the following factors:

poor qality; srpls water in the system; very

small qantity; or isolated location. If water qality

is acceptable, consider an athorized discharge in

consltation with DWAF.

• Discharge/dispose: All potential dischargesconsidered shold be discssed with DWAF in terms

of discharge points and qality limits. All discharges

or disposals reqire an athorization (NWA, Section

21). Specialist investigations and ris assessments

may be reqired.

• Treatment: Decide on a potential water treatment

technology (active or passive, chemical or biological)

based on contaminants of concern. Refer to BPG H4:

Water Treatment and also consider the following:

- Water ser reqirements – mine/plant water

sers, srronding indstries, downstream

sers, aqatic ecosystem and environment;

- Technology reliability and technical feasibility;

- Treatment technology requirements - ow rate/

volme; qality; qantity and qality variation,

srface land area reqired and available;

- Reside/waste streams - characteristics,

disposal, redction of qantity, sldge

stabilization and stability, byprodct recovery;

- Financial reqirements and responsibilities -

capital cost and operating expenditre;

- Technology performance ris assessment

- performance redction or failre and its

impacts;

- Sstainability - different phases, life-cycle;

variations; and

- Laboratory/pilot plant stdies - address

ncertainties.

• Alternative uses: Reassess possible se of water

after treatment either on the mine/plant, at srronding

indstries or for downstream sers. Indstrial ecology

- introduce wastewater or efuent into external

recycling networks; one industry’s waste may become

another industry’s raw material.

• Monitoring:Institte monitoring and aditing to ensre

that adverse effects of nacceptable reclaimed water

qality are not manifested, i.e. corrosion, scaling,

redced process performance. Evalate performance

and implement corrective actions if necessary.

• Sustainability: Ensre water rese and reclamation

strategy is sustainable over the plant’s life cycle and

different hydrological cycles.

• Materials or byproduct recovery: Evalate waste

streams for properties that mae them sefl rather

than for properties that render them waste. Minimize

waste by retrieving/recovering sable process

materials and resorces from waste streams. Ths,not only water reclamation bt also reclamation of

chemicals for rese in process, new ses or sale.

• Future: Develop water and salt balance projections

(refer to BPG G2: Water and Salt Balances) for ftre

scenarios, inclding closre and post-closre. Long-

term planning and sstainability shold be considered

and therefore predictions on water qality and qantity

into the ftre shold also be incorporated (predictive

modeling) to ensre that rese and reclamation

strategies are not affected by ftre processes/plans.




____________________________________________________________________________________________________________________________________

32

10

PROCess ChANGes

OR CleANeR

TeChNOlOGy

(sTeP 9)




____________________________________________________________________________________________________________________________________

33

10.1 Need and signicance

Cleaner prodction technology and process changes/

modications are pro-active and preventative measures,

which aim for process- and/or prodct–integrated

solutions that are ecologically and economically efcient

(eco-efciency). The objective is to tackle possible

polltion problems before they develop rather than

remediate them after they have occrred, ths redcing

levels of polltants in waste streams (contaminants of

concern) prior to release or redcing water reqirements.

In this regard, cleaner prodction also ties in with

polltion prevention and redction. Cleaner prodction

is very mch in line with the DWAF water management

decision-maing hierarchy and international wastemanagement hierarchies, which also follow preventative

approaches. Maret and reglatory pressres lead most

companies to invest in the development or acqisition of

new technologies and management practices to achieve

cleaner prodction.

Cleaner production and process modications can

achieve the following:

• Higher production rates as unnecessary production

steps are eliminated throgh innovative process

integration;

• Minimize waste production and disposal by avoiding

heat degradation of prodcts, recycling, eliminating

spillages and fgitive emissions;

• Improved product quality and yield by considering

prodct life cycle assessment (how prodcts are

prodced, processing, extraction, manfactring,

etc., as an integrated approach);

• Increased operating or production efciency through

improved process selectivity and/or conversion and

more efcient equipment;

• Higher percentage on-line time and long campaign life

between rebuilds (shut-downs) through more efcient

eqipment design;

• Safe operating conditions considering for example

how waste is handled, transported and disposed of;

• Signicant reductions in environmental impact, in

terms of redced liqid/water, solid and gas/air

emission generation;

• Conservation of resources such as materials, energy

and water de to their redced se (for example

operating at lower temperatres and/or pressres);

• Reduced operating and/or production costs (compare

with conventional “end-of-pipe” clean-p technology);

and

• Decreased liabilities due to reduced environmental

impacts and waste prodction (minimization/redction,

rese, recovery and disposal).

Cleaner prodction therefore combines gains in

prodctivity with improvements in environmental

management. The mining indstry has already made

some progress by employing cleaner prodction

practices sch as redction in noxios air emissions,

decrease in levels of toxic contaminants in efuent

discharges, major pgrading in land management

etc. These improvements have led to a redction of

conventional end-of-pipe treatment in favor of polltionprevention practices at sorce. Integration of cleaner

technologies and strategies can be achieved by inclding

highly efcient equipment and control systems, state-

of-the-art environmental management measres and

comprehensive environmental management plans.

De to the large qantities of material, energy and

water sed in the mining and hydrometallrgical

industry, signicant opportunities are available for waste

redction/minimization and cleaner prodction. Polltion

prevention by “cleaner technologies” is important not only

becase of the environmental protection advantage bt

also becase of the cost savings associated with these.

Waste redction/minimization as sed in this context

refers to in-plant modications that reduce the volume

or degree of hazardosness of waste and wastewater

generated.

102 impmntaton

Cleaner production should address ve major areas of

bsiness:

• Policy development and institutional relations –

woring towards setting performance standards;establishing nancial arrangements and corporate

buy-in; implementing efcient environmental

management systems.

• Environmental and social impact assessment – using

social indicators to monitor societal effects over

time; promoting staeholder participation; monitoring

environmental impacts.

• Technological development – promoting research

and development; introdcing life-cycle assessment

to operations; developing technological soltions.




____________________________________________________________________________________________________________________________________

34

• Company strategy – continuously improving

management systems; monitoring predicted impacts

and nexpected events; designing incentives for

employees to engage in environmental practices.

• Education and training – enhancing environmental

awareness within the worforce; training for

innovative commnity relationships; collaborating

with independent agencies.

impmntaton tp:

• Identify existing and proven cleaner technologies

available on the maret.

• Assess existing cleaner technologies in terms of

applicability and practicality.

• Conduct feasibility study - analyze investment;research options or adaptations reqired, etc. May

inclde laboratory or pilot plant stdies.

• Monitor to ensure cleaner technologies play their

appropriate role over the long-term.

103 barrr prvntng canr

procton

Often barriers of an economical, technological and

legislative natre hinder the implementation or adoption

of cleaner technology bt these can be overcome throghimproved planning, employee edcation and increased

government intervention.

1031 economc arrr/contrant

Conventional end-of-pipe abatement reqires less

capital investment, less development and less disrption

to prodction processes than cleaner technologies and

strategies. Economic barriers are particlarly relevant to

smaller mining companies who have less fnds available

and are more economically driven. These companies

mostly eep to the minimm standard (discharge etc)

reqired withot prosection realizing that their operationmay still impact on the environment.

Commodity market price: The mining indstry cannot

control the vale of the commodity and a downtrn in

price affects how each mine is managed. A shift to

reglatory compliance is noted with price drops since

fnds are no longer available to invest in proactive

technologies. Economic pressres may force a company

to abandon “cleaner” methods and adopt less expensive

methods instead, which are more prone to environmental

degradation.

Lack of resources (fnds, time, personnel etc): A

limited environmental bdget restricts spending on highly

efcient, expensive pollution prevention and cleaner

prodction technologies and only a mode of reglatory

compliance is maintained. Limited bdget means less

personnel and time spent on this fnction as well.

Financial incentives: Incentives are needed to shift to a

mode of cleaner prodction and these are limited within

most governments.

1032 Tcnoog arrr

Structural barriers: Investments (nancial and

resorces) in crrent systems sed may prevent changes

to other technologies since a) employees with sills andknowledge pertaining to the specic current system

may then have to be trained in another technology or

otside assistance may be reqired, reqiring additional

investment; and b) the infrastrctre spports the crrent

system and applying a new technology may reqire

additional and/or new infrastrctre to be established,

reqiring frther investment.

Lack of time to conduct pilot plant or laboratory

studies: The mining indstry is pressed for time de to

prodction pressres and there is limited time available

to condct pilot plant and/or laboratory stdies to test theapplication and feasibility of new technologies. Research

and development are often not priorities as the focs is

on production. Industries therefore often nd themselves

going with a proven technology which is the safer option

in cases where no pilot plant or laboratory stdies have

been condcted (refer to BPG H4: Water Treatment ).

Lack of available systems: A signicant portion of

global mineral prodction originates from grassroots

operations, which lac the appropriate technologies

to avoid environmental problems. Also refer to small-

scale mining operations (refer to BPG A1: Small-scale

Mining ).

Technology and information gaps: Insufcient

nowledge of cleaner prodction and cleaner technologies

available on the international maret; ncertainty in

impact predictions; inactiveness in the environmental

management arena; shortage of necessary expertise;

lac of promotion and dissemination of cleaner

prodction and cleaner technologies may prevent its

implementation.




____________________________________________________________________________________________________________________________________

35

1033 lgatv arrr/prr

Environmental legislation is continally developing

and being amended/changed to sch an extent thatsystems that are now recognized as being effective

polltion prevention methods cold easily become

otdated in the years to come. The volatile natre of

best practice technologies and the freqently changing

reglatory environment maes the selection process for

environmental technologies difcult and can discourage

implementation of cleaner technologies. Crrent cleaner

technologies may in ftre be mere environmental

compliance machines. Ths changing reglations can

trn existing cleaner technologies into ftre compliance

investments. Mines, in general, therefore tend to operate

in line with set standards in environmental legislation

and only change operations when necessary. Long-

term planning to invest in proactive environmental

measures is difcult since it is difcult to hit a “moving

target”. Thogh Soth Africa as a developing contry has

strict environmental reglations, effective enforcement

programmes are often lacing thereby preventing the

implementation of cleaner prodction.

Environmental legislation shold inclde:

• Clear, continuous policies to support waste

minimization and cleaner prodction.

• Regulatory frameworks and enforcement.• Consideration of characteristics of industrial

prodction processes.

• Clear understanding of the difference between

compliance investments and cleaner technology.

• Coordination among different governmental agencies

at different levels.

104 Ovrcomng arrr

1041 Govrnmnta ntrvnton

Often nancial support and appropriate technology is

reqired to improve prodction processes. Government

shold tae a leading role in promoting cleaner

prodction and indicate it as a national and provincial

goal for economic and environmental policy. Priorities

may inclde:

• Economic instruments and assistance: Economic

instruments or nancial incentives to motivate mines

to implement cleaner prodction may inclde levies,

tax breas and sbsidies. Government crrently

nances research such as that by the Water Research

Commission (WRC) and provides gidelines sch

as the BPG series. Ensring that bans, insrance

companies and other lending instittions favor

cleaner technologies in their investment decisions.

• Technical incentives and assistance: Woring

with edcational facilities (niversities) and private

sector (indstry). Government-academic-indstrial

partnerships. Each partner provides a different area

of expertise (technical, training and edcation).

Environmental technology demonstration projects.

• Provision of information: Government to obtain

and disseminate appropriate information concerning

cleaner technologies and strategies, otlining their

contribtion to economic aims. Provide docmented

reslts of sccessfl cases and edcational materials

in press.

• Certication: Developing and implementing a

cleaner technology certication system for products,

processes and services.

1042 ecaton an tranng

Edcation and training is reqired for an increased level

of awareness and to increase employee and commnity

nowledge. Awareness training shold not only aim to

acqaint people with environmental problems bt also

to ensre that ecological effects are flly nderstood.

Edcation shold be inclded for employees involved in

research, material prchasing, environmental eqipment

design, installations, running and management of nal

technological setps. Promotion campaigns for cleaner

technology will also contribte to creating awareness.

1043 improv pannng

For new mines, environmental isses mst be acconted

for in the original bleprints. An inventoried listing of

environmental technologies, treatment processes, and

toxic chemicals sed, shold be made p front. In the

design of the mine, ecological “sitations” shold be

acconted for when determining where to implement

specic environmental technologies.

For existing mines, an environmental management

system (EMS) wold ensre more effective control

and redce environmental impacts and shold inclde

organizational procedres, responsibilities, processes,

implementation strategies, measrement and evalation

criteria, efciency measures and goals for improvement.

Environmental adits at reglar intervals can also be

implemented and shold inclde a thorogh investigation

of every indstrial system and process. Environmental

monitoring and technological assessments are also

important.




____________________________________________________________________________________________________________________________________

36

11

iNTeGRATedWATeR ANd WAsTe

MANAGeMeNT PlAN

(sTePs 10 ANd 11)




____________________________________________________________________________________________________________________________________

37

The integrated water and waste management plan

(IWWMP) shold aim to continosly and systematically

redce waste generation, prevent polltion and minimize

impacts.

To implement a comprehensive IWWMP, the following is

reqired:

• Adequate resources in terms of nances, competent

personnel, infrastrctre and other reqirements.

• Commitment of the company, management and

employees to the objectives of the IWWMP.

• Montorng which incldes data and information

collection, cost acconting and feasibility analysis

(continos review).

• Environmental impact monitoring and environmentalpolicies to achieve improved environmental goals.

• Training and awareness programmes emphasizing

polltion prevention, impact minimization and control/

management.

• Hydrometallurgical plants designed to better

accommodate wastes, prevent polltion and minimize

impacts.

• Baseline and continual operational monitoring (refer

to BPG G3: Water Monitoring Systems) of grond,

srface and process water as well as eqipment

and the sbseqent implementation of action plans based on the reslts.

The IWWMP shold inclde detailed discssions on the

following sbjects:

• General information: Applicant details, holding

company details, plant locality, spporting srface

infrastrctre (road, rail, power), land ownership and

se, plant srface infrastrctre, processes (raw

materials and chemicals, prodcts and waste).

• Legislation: Applicable legislation, existing permits,

legal reqirements.

• Current water environment:

- Climate – regional; temperatre; precipitation;

evaporation; wind; extremes.

- Topography and geology.

- Srface water catchment - water corses (rivers/

streams) and dams; wetlands.

- Affected grondwater zone – aqifers; boreholes;

springs.

- Water quantity (volumes/ows/yields) and quality

- monitoring points, freqency, parameters,

baseline and operational; data management.

- Water authority (regional DWAF ofce); water

ses (plant and downstream); water spply.

• Water management:

- Water sorces – availability; spply and available

to operation; droght and water restrictions; water

service providers; water sppliers; srronding

indstries with excess water, boreholes, srface

water bodies (streams/dams), process water on

the mine/plant.

- Water rights - legal standing; licence conditions.

- Water sers on mine/plant - consmption

patterns; individal processes; water

reqirements in terms of qantity and qality;

sensitivity to variations.

- Water rese and reclamation (refer to BPG H3:

Water Reuse and Reclamation). Refer to Step

8, Chapter 9.

- Water conservation - minimisation of water

se; long term redction of consmption; set

objectives.

- Process water management - water and salt

balance; possible polltion sorces; polltion

prevention measres; minimisation of waste

loads in water; high contamination ris areas;

safety factors; system failres; accident andemergency plans; monitoring and aditing. See

Chapter 7.

- Storm water management - separation of clean

and contaminated storm water; release of clean

storm water; containment of contaminated storm

water; maintenance; erosion and sediment

control. See Chapter 7.

- Grondwater management – possible polltion

sorces; polltion prevention measres;

polltion plmes; impacts; management

measres; monitoring.- Water treatment (refer to BPG H4: Water

Treatment ).

- Disposal/discharge – alternatives/options

considered; socio-economic impacts; impact

assessment; monitoring; management; nancial

provision; consltation with DWAF.

• Waste management: Site selection; classication

of waste; hazardos sbstances in waste; handling;

transport; leach potential; lining systems; leachate

interception; disposal practices etc.




____________________________________________________________________________________________________________________________________

38

• Commitments:

- Monitoring – water and waste qality and qantity;

monitoring points; freqency; parameters;

baseline; operational; data management;

record-eeping; impact and ris assessments;

performance reviews; inspections and adits;

indicate action/target levels and water qality

objectives.

- Management – maintenance; minimizing

impacts; polltion prevention; minimize

discharges/seepage; set targets; health of

water dependent ecosystems; reporting to

management; reporting to athorities; training;

responsibilities; accontability; emergency and

contingency measres; review processes in

place and implement action plans as reqired;performance indicators to evalate sccess of

management strategies and plans.

• Consultation process: Staeholder commnication;

reglatory athorities; interested and affected

parties; commnity expectations; forms/process

for information sharing; meetings; database; pblic

participation; advertisements and notications

in media; complaints register; water as a shared

commnity resorce; respect water rights of other

sers; consider downstream water qality problems

(DWAF water quality guidelines for specic uses).

For each water se it is therefore important to ensre the

following points are addressed:

• problem statement and/or impact;

• management plan or operational procedures;

• maintenance and inspections procedures;

• performance indicators and compliance monitoring;

and

• emergency contingency procedures.

Water and waste management system designs shold

be based on the following considerations:

• Pilot scale testing is not considered completely

reliable.

• The treatment of supply water is seldom a viable option

de to the complexity of water treatment processes

and sldges prodced as well as the cost associated

with treatment and sldge management. However,

intae water or raw water qality deteriorates and

the industry may nd itself required to pre-treat water

for sage in certain nit processes (refer to BPG

H4: Water Treatment ). Loo at new water treatment

technology.

• Flexibility should be incorporated into the reticulation,

storage and distribtion systems and networs to

ensure efciency. Systems must be able to absorb

variations/srges and spply a variable demand fromnit processes. Design based on average process

ows is thus inappropriate. Centralized water storage

facilities shold be considered (refer to BPG G1:

Storm Water Management ).

• Consider water demand and efuent generation

patterns of different nit processes. For example

water available from shaft dewatering peas over the

weeend whereas consmption of water by the plant

tails off dring this period. Process or contaminated

storm water mst be consmed in preference to

raw water (refer to BPG H3: Water Reuse and

Reclamation). Also consider mineral and prodctrecovery from efuent streams in future.

• Numerous unit processes exist, each with their own

demands patterns and water qality objectives.

unit processes mst manage their own water

systems throgh a water and salt balance (refer to

BPG G2: Water and Salt Balances). An efuent

generator remains responsible for the water ntil it is

absorbed in an alternative nit process or disposed

of in accordance with water qality objectives for the

catchment.

• Contamination of water used to transport material

leads to progressive deterioration of water retrnedand available as process water. Consider closed

circits or separate circits in certain instances.

• Increasing volumes of water to be managed increases

reqirements for pmp, piping and storage facilities

thereby increasing cost.

• Minimize contaminants discharge/emission;

inefciency and wastage; contribution to specic

environmental problems; overall environmental

impact.

• Improve automation and communication systems.

There is also the temptation to follow a principle of “minimm compliance” where costs are not considered to

be signicant. This type of water and waste management

(reactive or ad-hoc) is less efcient and environmentally

friendly than a pro-active system with fll commitment

to effective management of the water cycle. An effective

water and waste management system establishes

objectives and ensres these are integrated into the

day-to-day management of the mine/plant. A water

management system mst therefore satisfy the qality

and qantity demands by all nit processes bt also the

objectives of the environment on which it impacts.




____________________________________________________________________________________________________________________________________

39

The proposed strctre and contents of an IWWMP is

as follows:

i eXeCuTiVe suMMARy

Briey covering:

• Background

• Process description

• Environmental description

• Water system characterization

• Management Programmes

- Waste Minimization and Recycling

- Water Use Efciency

- Water Containing Waste

- Storm Water Management

- Grondwater Management

- Remediation and Rehabilitation

- Water Monitoring

- Emergency and Contingency Discharge

Management

ii MAiN dOCuMeNT

1 Introdction

1.1 Bacgrond

1.2 Contact Details

1.3 Location of project

1.4 Property description

1.5 Legal Assessment

1.5.1 Existing Lawful Uses

1.5.2 Summary of Water Uses

1.5.3 Summary of Relevant Exemptions

1.5.4 Summary of General Authorizations

1.6 Section 27 Motivation

2 Projct dcrpton

2.1 Prpose of the Docment

2.2 Objectives of the project

2.3 Physical project description

2.3.1 Extent of operation

2.3.2 Mining method

2.3.3 Project life description

2.3.4 Infrastructure requirements

2.4 Reside and Emissions

2.4.1 WasteStreamIdentication

2.4.2 Waste Stream Characterisation2.4.3 Waste Management

2.4.4 Waste Recovery and Reduction

3 envronmnta stat qo

3.1 Climate

3.1.1 Regional Climate

3.1.1.1 Mean rainfall

3.1.1.2 Evaporation

3.1.1.3 Maximm Rainfall

3.1.1.4 Temperatres

3.1.1.5 Meteorological climate

3.2 Soil and Land capability

3.3 Srface Water

3.3.1 Water Management Area

3.3.2 Srface Water Hydrology

3.3.3 Srface Water Qality

3.3.4 Mean Annal Rnoff (MAR)

3.3.5 Resource Class and River Health

(Applicant)

3.3.6 Set Resource Class Objectives

(DWAF/Reserve)

3.3.7 Surface Water User Survey

3.3.8 Sensitive Areas Survey

3.4 Grondwater

3.4.1 Aquifer Characterisation

3.4.2 Groundwater Quality

3.4.3 Hydro-census

3.4.4 Potential Pollution Source

Identication

3.4.5 Groundwater Model

3.5 Socio-economic Environment

4 Qanttatv Rk Amnt

4.1 Safety, Health, Environment and Qality

Policy

4.2 Objectives and Strategies

4.3 key Performance Area and Indicators

4.4 Methodology Followed




____________________________________________________________________________________________________________________________________

40

4.5 Possible Impacts on the Environment

4.6 Signicance of possible impacts

4.7 Ris to the Environment4.8 Riss to hman health

5 Cost-benet analysis

5.1 Methodology and Selection Criteria

5.2 Management Options (Evalation of

alternative options)

5.2.1 Short-term alternatives

5.2.2 Long-term alternatives

5.3 Selected Management of Identied Risks

5.3.1 Short-term solutions5.3.2 Long-Term Solutions

5.4 Financial Provisioning

6 intgrat envronmnta Managmnt

6.1 Environmental Management Philosophy

6.2 Environmental Management Systems

6.3 Water use and Management

6.3.1 Water Spply

6.3.2 Potable water spply

6.3.3 Process water spply

6.3.4 Clean water management facilities

6.3.5 Dirty water containments systems

6.3.6 Sewage Management Facilities

6.3.7 Storm Water Management

6.3.8 Operational Water Balance

6.4 Solid Waste Management

6.4.1 Domestic waste

6.4.2 Industrial Waste

6.4.3 Hazardous Industrial Waste

6.4.4 Other wastes

6.5 Rehabilitation and Mitigatory measres

6.6 Soil and Land Capability Management

7 Montorng tm

7.1 Water Monitoring

7.1.1 Groundwater Monitoring

7.1.2 Surface Water Monitoring

7.1.3 Bio-monitoring

7.2 Data Management and Reporting

7.3 Waste monitoring

7.3.1 Waste Rock

7.3.2 Mine Tailings

7.3.3 Slime wastes

7.3.4 Slag wastes

7.4 Environmental Management System

7.5 Recording of Incidents

7.6 Environmental Impact Register

7.7 Aditing and Reporting

8 Opratona Managmnt

8.1 Organisational Strctre

8.2 Environmental Management: Resorces

8.3 Awareness and Training

8.4 Commnication

8.4.1 IdenticationofStakeholders

8.4.2 Public liaison and forum participation

8.4.3 Distribution of information

8.4.4 Public meeting

8.4.5 Documents for public review

9 Rfrnc an spcat t




____________________________________________________________________________________________________________________________________

41

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45

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Managing process water quality in base metal sulde

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A2 Gnrc conttnt of concrn

n romtargca procng

Broadhrst (2007) smmarized the generic groping of

the constitents of concern to tie p with potential water management objectives as follows:

Dissolved solids - expressed as total dissolved solids

(TDS), electrical condctivity (EC) or ionic strength: The

presence of salts can generally be lined to both feed

ores and processing operations (e.g. as leachants etc).

Salts can be divided into two frther sb-grops:

• Major solble salts: These inclde the slphates,

chlorides and carbonates of Ca, Mg, Na and k. These

salts are relatively abndant and common in natral

environments and ncontaminated water de to their

abundance in the earth’s crust and their relative highsolbility. They are all essential elements and only

exhibit toxic effects at relatively high concentrations.

Gidelines are based on aesthetic and physical

properties rather than toxicity. They are the major

cases of corrosion and scaling of plant eqipments

and, as a combined grop, can reslt in salinization of

soil and water resorces.

• Minor solble salts: These inclde F, Br, I, phosphate,

nitrate and nitrite salts. These salts are also essential

elements, bt are generally present at lower

concentration levels in natral environments and

have a greater toxicity than the major solble salts.

Trace metals and semi-metals: These generally

arise from the feed ore. These elements can vary qite

considerably in terms of both their biological effect and

environmental concentrations. These, thogh present in

the earth’s crust, do not occur in a natural uncontaminated

environment in solble or bioavailable form.

Anthropogenic processing reagents: These inclde

plant inpt reagents or chemicals prodced as side-

prodcts dring processing which do not generally occr

in natral environments. These inclde cyanide, organic

extractants, and srfactants (oil, grease, tars etc). These

elements are generally non-essential and harmfl to the

eco-system and mammals at low concentrations. There

are however, generally more opportnities to redce

these at sorce than those elements arising from the

feed ore.

Physical characteristics: These comprise mainly of pH

and sspended solids and have a greater effect on plant

performance (corrosion, scaling etc). The main effect of

pH is indirect, as pH has an inuence on solubility. pH

is therefore considered to be one of the main variables

controlling the leachability of constitents from materials

(also redox potential).

A3 Pca watr-rat prom

xprnc n t ro-

mtargca ntr

In hydrometallrgical processing, the need for higher

mineral recoveries has led to more elaborate recovery

methods, most of which involve the extensive se and

recycling of water. These operations necessitate stricter

control over the condition of the circit/process water in

order to maintain efciencies and to avoid water-related

operational problems sch as scaling, corrosion andfoling which are discssed in Table A.2 below.

The solble inorganic componds most commonly

encontered in these waters are a sorce of potential

troble throgh deposition in water pipes, eqipment

and boiler tbes. Contingency action plans to handle

redced process performance or process failre shold

also consider these in that deposits might have formed

and once process conditions have been corrected, these

deposits may still exist and need to be dealt with.

In the operation of every cooling, heating and steam

generating system, the water changes temperatre.

Higher temperatres and sbstance bild-p increase

both corrosion rates and scale forming tendencies.

Evaporation in open cooling systems and boilers

increases the dissolved solids content of the remaining

water and these increased concentrations can become

the cause of either scale formation or intensied corrosion

nless corrective treatment is applied. Sspended

solids or microbial organisms, in the mae-p water or

scrbbed from the air, can reslt in considerable physical

and microbial foling problems.




____________________________________________________________________________________________________________________________________

46

Ta A2: Watr-rat prom xprnc

scang Corroon Fong

Denition Precipitation of sbstances,whose solbility in water hasbeen exceeded, in a verydense and adherent form, ontothe srronding srfaces.

Metal reverts to a compondsimilar to those fond innatre. Electrochemicalprocess in water.

Deposits form from materialsspended in water or fromgrowth of microbiologicalorganisms. Often associatedwith scaling and/or corrosion.

Origin/formation/case

Change in water temperatre or increase/decrease indissolved solids content or concentration, specically calciumand magnesim. Pipe velocity (speed at which water isconveyed)

Sspended solids or microbialorganisms in mae-p water or scrbbed from the air.

Physicalrecognition

A chemical deposit (material)bilding p on the srfacethereby clogging the pipes.

Thinning of metal; metal iseaten away.

Bild-p of material onto thesrface thereby clogging thepipes.

Effects Affect heat transfer rates.Impede ow of liquids.

Process throghpt may bedecreased de to redcedow.

Plg distribtion systems.

Waste of sefl metal. Highmaintenance cost.

Affect heat transfer rates.Impede ow of liquids.

Create differential concentrationcell corrosion.

Harbor anaerobic corrosivebacteria.

Plg distribtion systems.

Factors reqiredfor formation

Spersatration.

Ncleation.

Adeqate contact time for

adherence.

usally nder cathodiccontrol (cathode reaction israte determining).

uneconomical to eliminate- control rate by controllingpH, EC and alalinity.

Material sspended in water.

Microbiological organisms(bacteria, algae, fngi).

Factorspromotingformation

Increased pH.

Increase temperatre.

Reduced ow velocity.

Long lengths of piping.

Dissolved gasses (O2, CO

2,

H2S, NH

3).

Dissolved solidsconcentration (increasedEC, SO

4and Cl interfere

with protective lm).

Increased temperatre -increase chemical reactionrate.

Differential concentrationcells (galvanic crrent nder deposits).

Large volme pmps.

Conditions for growth of microbiological organisms.

Reduced ow velocity.

Ammonia, carbon componds,hydrocarbons (oil), phosphatesas ntrients for microbialorganisms.

Examples of types

Calcim carbonate

Calcim slphate

Magnesim silicate

Iron oxides

General srface corrosion.

Pitting (crater-lie), incldinggalvanic.

Physical.

Microbiological.




____________________________________________________________________________________________________________________________________

47

scang Corroon Fong

Monitoring Deposit monitors, chemical

analysis, deposit analysis.

Corrosion copons,

electrical devices, depositmonitors, chemicalanalyzers, test heatexchangers, eqipmentinspections.

Deposit monitors, chemical

analysis, deposit analysis,biological monitoring (bacterialconts).

Inhibition or control

Limit critical specieconcentration (controlledbleeding or pretreatment).

Redce alalinity (acid dosing).

Alter system design or operation (increase ow,

redce temperatre, limitpasses in heat exchanger,reduce heat uxes bydecreasing heat load or increasing size)

Inhibitors (threshold inhibition,crystal modication, chelation,dispersion, conditioning for sldge formation).

Maintain srfaces deposit free.

Increase pipe velocity (>2m/s).

Inhibitors interfere withanodic or cathodic reactions:

Anodic – chromate,orthophosphate, nitrite,silicate, ferrocyanide;Cathodic – calcimcarbonate, polyphosphate,

zinc, magnesim; Anodicand cathodic – organiclming amines.

Metallic coatings.

Control water chemistry.

Oxidizers (chromate).

Film formers (solble oil,phosphates).

Reactive metal (Mg/Znblocks as sacricial anodes).

Increase pipe velocity(> 2m/s).

Water clarication (inorganicand polyelectrolyte polymer occulants).

System design (ensre trblentow).

Limit concentrations (decrease

by increasing blowdown rate).Slipstream lters (reducesspended solids).

Air rumbling and back ushing(pressrized air stream toincrease ow velocity, dislodgematter settled in low ow areas).

Limit ntrients for organisms.

Dispersants (bio or chemical).

Biocides (penetrants or dispersants)




____________________________________________________________________________________________________________________________________

48

Below are a number of process ow sheets taken from the WRC report 1550/1/07 (Broadhurst,

Hansen and Petrie: 2007) representing some of the different sb-sectors in the mining and

mineral processing industry. A process ow sheet is a representation or schematic diagram

showing the steps of a process in seqential order. These are for example prposes only andtherefore not discssed in detail bt merely explained in terms of the terminology. Frther

discssion and information is contained in the WRC report and reference shold be made to

this for frther detail.

APPeNdiX b:

VARiOus hydRO-

MeTAlluRGiCAl

PROCesses

Figure B.1: Coal hydrometallurgical processing ow sheet (WRC 1550/1/07)




____________________________________________________________________________________________________________________________________

49

Figure B.2: Gold hydrometallurgical processing ow sheet (WRC 1550/1/07)




____________________________________________________________________________________________________________________________________

50

Figure B.3: PGM hydrometallurgical processing initial beneciation ow sheet (WRC 1550/1/07)




____________________________________________________________________________________________________________________________________

51

Figure B.4: PGM base metals rening ow sheet (WRC 1550/1/07)




____________________________________________________________________________________________________________________________________

52

Figure B.5: General ferro-alloy ore processing ow sheet (WRC 1550/1/07)

Figure B.6: Stainless steel ow sheet (WRC 1550/1/07)

See WRC 1550/1/07 for further ow sheets on Fe-Si, Si-Mn, Fe-Cr, Fe-Mn, Fe-V.




____________________________________________________________________________________________________________________________________

55

TeRM AbbReViATiON deFiNiTiON

Basic Oxygen

Frnace3

BOF A towering cylinder lined with heat-resistant (refractory) brics,

sed by integrated steel mills to smelt iron from iron ore. Its namecomes from the “blast” of hot air and gases forced p throgh the

iron ore, coe, and limestone that load the frnace.

Calciner/Calcining

Frnace2

A heating device, sch as a vertical-shaft iln, that raises the

temperatre (bt not to the melting point) of a sbstance sch as

limestone to mae lime.

Calcine2 To heat (a sbstance) to a high temperatre bt below the melting

or fsing point, casing loss of moistre, redction or oxidation,

and the decomposition of carbonates and other componds.

Cementation2 A metallrgical coating process in which iron or steel is immersed

in a powder of another metal, sch as zinc, chromim, or

alminim, and heated to a temperatre below the melting point of either.

Cementation is the process by which one sbstance is cased to

penetrate and change the character of another by the action of

heat below the melting points of the sbstances.

Carbon in

Leach2

CIL Activated carbon is added to a gold ore slrry contained in

leach tans. The carbon adsorbs the gold from the soltion as

cyanidation of the ore proceeds.

Carbon in

Plp2

CIP Milled gold bearing ore is mixed with a cyanide soltion, which

cases the gold to complex with the cyanide, and activated

carbon particles. The activated carbon is pmped p throgh

tans conter-crrent to the cyanide slrry soltion. As activated

carbon and loaded cyanide soltion meet, the solble gold-cyanide

complex adsorbs to the activated carbon. These particles are

removed from the slrry and gold is recovered.

Clarier 2 A piece of equipment used to lter a liquid.

Conditioning A process in which reagents and ore are allowed to come to steady

state before frther processing of the ore contines.

Convert2 To change (something) into another form, sbstance, state, or

prodct.

Corex3 COREX® is a patented coal-based smelting process that yields

hot metal or pig iron. The otpt can be sed by integrated mills or

EAF mills.Dense Media

Separation4

DMS Separation of relatively light (oats) and heavy (sinks) particles, by

immersion in a bath of intermediate density. This is the dense or

heavy media, a nely ground slurry of appropriate heavy material

in water. Barite, magnetite ferrosilicon, and galena are in principal

se.

Direct Redced Iron3 DRI DRI is processed iron ore that is iron-rich enogh to be sed as a

scrap sbstitte in electric frnace steelmaing.




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56


Electric Arc Frnace3 EAF Steel-maing frnace where scrap is generally 100% of the

charge. Heat is spplied from electricity that arcs from thegraphite electrodes to the metal bath. Frnaces may be either an

alternating crrent (AC) or direct crrent (DC).

Electrostatic

Separation2

Process of separating non-condctive particles from condcting

particles. Electrostatic separation of nely pulverized materials is

carried ot in electrostatic separators.

Electrowin5 EW Most metals occr in natre in oxidized form in their ores and

ths mst be redced to their metallic forms. The ore is dissolved

following some pre-processing in an aqeos electrolyte or in a

molten salt and the reslting soltion is electrolyzed. The metal is

deposited on the cathode (either in solid or in liqid form), while

the anodic reaction is sally oxygen evoltion. Several metals are

natrally present as metal slphides; these inclde copper, lead,

molybdenm, cadmim, nicel, silver, cobalt and zinc. In addition,

gold and platinm grop metals are associated with slphidic base

metal ores. Most metal slphides or their salts are electrically

condctive and this allows electrochemical redox reactions to

efciently occur in the molten state or in aqueous solutions.

Ferro Alloy5 Any alloy of iron and another metal, especially one of silicon,

manganese, chromim and vanadim, sed in the prodction of

specialist steels as they have a lower melting point than the pre

metal.

Flotation2 The process of separating different materials, especially minerals,

by agitating a plverized mixtre of the materials with water, oil,and chemicals. Differential wetting of the sspended particles

cases nwetted particles to be carried by air bbbles to the

srface for collection.

Gravity

Concentration2

Any of varios methods for separating a mixtre of particles, sch

as minerals, based on the differences in density of the varios

species and on the resistance to relative motion exerted pon

the particles by the uid or semi uid medium in which separation

taes place. The separation of liqid-liqid dispersions based on

settling ot of the dense phase by gravity.

Gravity Separation6 If there is a certain difference in density between two minerals

or roc fractions they can be separated by sing this difference.

Separation by gravity covers two different methods.

Separation in water (Gravity concentration)

Separation in a heavy medim (Dense Media Separation, DMS)

Hot Acid Leach HAL A hot slphric acid leach (HAL) circit to remove iron coatings

from the non-magnetic heavy minerals dring mineral sands

beneciation

____________________________________________________4 http: www.maden.hacettepe.edu.tr/dmmrt/dmmrt320.html




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57


Leach3 In the chemical processing indstry, leaching is nown as

extraction. Leaching has a variety of commercial applications,inclding separation of metal from ore sing acid.

In a typical leaching operation, the solid mixtre to be separated

consists of particles, inert insolble carrier A and solte B. The

solvent, C, is added to the mixtre to selectively dissolve B. The

overow from the stage is free of solids and consists of only

solvent C and dissolved B. The underow consists of slurry of

liquid of similar composition in the liquid overow and solid carrier

A. In an ideal leaching eqilibrim stage, all the solte is dissolved

by the solvent; none of the carrier is dissolved. The mass ratio

of the solid to liquid in the underow is dependent on the type of

eqipment sed and properties of the two phases.

Leaching is widely sed in extractive metallrgy since many

metals can form solble salts in aqeos media. Compared to

pyrometallrgical operations, leaching is easier to perform and

mch less harmfl, becase no gaseos polltion occrs. The

only drawback of leaching is its lower efciency caused by the low

temperatres of the operation, which dramatically affect chemical

reaction rates.

There are a variety of leaching processes, usually classied by

the types of reagents sed in the operation. The reagents reqired

depend on the ores or pre-treated material to be processed. A

typical feed for leaching is either oxide or slphide.

Magnetic Separation4 By creating an environment comprising a magnetic force (Fm), agravitational force (Fg) and a drag force (Fd) magnetic particles

can be separated from nonmagnetic particles by magnetic

separation. Magnetic separation is widely sed to remove tramp

iron from ores being crshed, to remove contaminating magnetics

from food and indstrial prodcts, to recover magnetite and

ferrosilicon in the oat-sink methods of ore concentration, and to

pgrade or concentrate ores. Magnetic separators are extensively

sed to concentrate ores, particlarly iron ores, when one of the

principal constitents is magnetic.

Matte2 A mixtre of a metal with its slphides, prodced by smelting the

slphide ores of copper, lead, or nicel.

Mill2 To grind, plverize, or brea down into smaller particles in a mill.

___________________________________________5 www.wikipaedia.com6 http://www.metsominerals.com/inetMinerals/mm_home.nsf/FR?ReadFormandATL=/inetMinerals/mm_segments.nsf/WebWID/WTB-041213-2256F-

B42B4




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59


Sinter 2 Process in which a coherent bonded mass (sinter) is formed by

heating metal powders withot melting; sed mostly in powder metallrgy.

Separation6 After liberation of all individal minerals in a roc or an ore feed,

either by grinding or by natral size redction (beach sands a.o.)

they can be separated individally. Depending on their behavior,

different technologies are applied.

Slag5 Slags are the by-prodct of smelting ore to prify metals. They can

be considered to be a mixtre of metal oxides; however, they can

contain metal slphides and metal atoms in the elemental form.

While slags are generally sed as a waste removal mechanism

in metal smelting, they can also serve other prposes, sch as

assisting in smelt temperatre control and minimizing re-oxidationof the nal bullion product before casting.

In natre, the ores of metals sch as iron, copper, lead, alminim,

and other metals are fond in impre states, often oxidized and

mixed in with silicates of other metals.

Dring smelting, when the ore is exposed to high temperatres,

these imprities are separated from the molten metal and can be

removed. The collection of componds that is removed is the slag.

Different smelting processes prodce different slags. In general

they can be classied as ferrous or non-ferrous. The smelting of

copper and lead in non-ferros smelting, for instance, is designed

to remove the iron and silica that often occrs with those ores andseparates it as an iron silicate based slag. Slag from steel mills in

ferros smelting, on the other hand, is designed to minimise iron

loss and so mainly contains calcim, magnesim, and alminim.

Slag has many commercial ses, and is rarely thrown away. It is

often reprocessed to separate any other metals that it may contain.

The remnants of this recovery can be sed in railroad trac ballast,

and as fertilizer. It has been sed as a road metal and as a cheap

and drable means of roghening sloping faces of seawalls in

order to progressively arrest the movement of waves.

Grond granlated slag is often sed in concrete in combination

with Portland cement as part of a blended cement. Grond

granlated slag has latent hydralic properties, which means thatit reacts with water to prodce cementitios properties. Concrete

containing grond granlated slag develops strength over a

longer period, leading to redced permeability and better drability

properties. Since the nit volme of Portland cement will also be

redced, concrete is less vlnerable to alali-silica and slphate

attac.

Slimes Ore that has been milled to such a ne grind that, when mixed with

water, it forms a slime material.




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60


Slow Cool Matte from a smelter is pored into a mold and allowed to cool

extremely slowly (over a period of days) in order to prodcevarios crystalline prodcts allowing frther separation of material

downstream.

Smelter 2, 5 A smelter is a specialised metallrgical frnace that allows smelting

to occr. Smelting is a method of separating gold, silver, and other

metals from their ores with re and heat intense enough to melt the

ores.

Solvent Extraction2 SX A techniqe, also called liqid extraction, for separating the

components of a liqid soltion. This techniqe depends pon the

selective dissolving of one or more constitents of the soltion

into a sitable immiscible liqid solvent. It is particlarly sefl

indstrially for separation of the constitents of a mixtre according

to chemical type, especially when methods that depend pon

different physical properties, sch as the separation by distillation

of sbstances of different vapor pressres, either fail entirely or

become too expensive.

Indstrial plants sing solvent extraction reqire eqipment for

carrying ot the extraction itself (extractor) and for essentially

complete recovery of the solvent for rese, sally by distillation.

See also Distillation.

Tailings Tailings (also nown as tailings pile, slicens[1] or gange) are the

waste materials left over[2] after removing the minerals from ore.

Tailings and gange represent external costs of mining. As mining

techniqes and the price of minerals improve, it is not nsal for tailings to be reprocessed sing new methods, or more thoroghly

with old methods, to recover additional minerals.

In coal and oil sands mining, the word ‘tailings’ refers specically to

ne waste suspended in water and the word ‘gangue’ is not used.

Thicener 5 A non-lter device for the removal of liquid from a liquid-solids

slrry to give a dewatered (thicened) solids prodct; can be by

gravity settling or centrifgation.

Waste Roc/

Overbrden2

Material overlying a sefl mineral deposit.

ZADRA Elution1 A process for the removal or recovery of gold from activated

carbon (see AARL eltion)




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61

A strategy for the ris-based environmental assessment of a proposed new hydrometallrgical

process plant is presented in this docment. This is a practical strategy that was actally

implemented for a new process that was developed before the rst plant was built. The process

that was followed is shown in Figre C1 below.

Fgr C1: envronmnta Rk Amnt Proc

APPeNdiX C:

eXAMPle OF

deTAiled RisK

AssessMeNT

PROCess AT PlANT

desiGN sTAGe

stp 1: Prpar or otan

matra aanc aron t

mtargca proc

A detailed material balance mst be

constrcted arond the metallrgical

process (inclding all air, solid and liqid

control systems). The balance will inclde

all inpts raw materials, ore, chemicals,

water) and all otpts (prodcts, air

emissions, solid wastes, liqid wastes).

In ndertaing the balance, it will be important




____________________________________________________________________________________________________________________________________

63

to ndertae probabilistic modelling in order to properly

dene the resultant material balances.

Step 4: Dene industry norms andtanar (ncmark)

If there are no other identical process plants in operation

and therefore, no norms or standards for environmental

emissions, sch norms and standards shold be

available for other similar processes. The emission

norms and standards for these applicable processes

shold be collated into a reference docment. The norms

and standards will include denition of “Best Available

Technology” in terms of emission controls as specied

internationally.

Step 5: Dene minimum legal/regulatoryrqrmnt

The legal and reglatory reqirements which will apply

to the planned process plant must be dened for the

Soth African sitation. Whereas it will be important to

ensre that the proposed process complies with legal

and reglatory reqirements, these reqirements shold

be viewed as the minimm, and the environmentalris assessment process shold evalate the real

environmental problems independently of these

reqirements. The reason for adopting the ris approach

is that the reglatory reqirements reglarly change and

lining the performance of the proposed process to these

changing goalposts will make it difcult to dene and

manage the environmental performance over the whole

plant life cycle.

stp 6: unrtak nvronmnta rk/

mpact amnt of proc

The environmental ris/impact assessment process

shold be rigoros and designed to withstand any local

or international scrtiny. This Step of the overall process

has been frther divided into 5 separate tass as shown

in Figre C3 and described in the text.

Fgr C3: dta envronmnta Rk/impact Amnt Proc




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64

Tak A: evaat matra aanc prpar n

stp 1 an 3

The material balances which were prepared in Steps 1and 3 should be critically evaluated in order to dene

those aspects which pose some potential environmental

ris. Particlar focs shold be placed on the varios

waste streams which are generated, their proposed

disposal rotes and any environmental riss/impacts

which may arise there, both throgh application of

approved management and operation procedres and

throgh failre of these approved procedres. This tas

should culminate in the denition of all contaminant

sorce terms in terms of location, qantity and qality for

best and worst case scenarios.

Tak b: Prpar ta nvronmnta

patwa mo for proc, ncng a

mon

Tas C and the sbseqent Tass D and E apply for the

assessment of the site-specic risks of the process at a

particlar location. The potential critical receptors mst

be dened for each of the best and worst case scenarios

identied in Task A. The critical receptor concept is based

on dening a hypothetical, conservative but realistic

hman or ecological receptor which may be affected by

the proposed process and its waste streams throgh one

or more pathways. The critical receptor(s) is/are chosen

to represent the most highly impacted-pon receptors

such that there is condence that if the critical receptor

is assessed to be exposed to an acceptable ris, then

all other potentially exposed receptors are sbject to an

even lower ris.

Using the identied critical receptors, a comprehensive

contaminant and exposre pathway analysis shold

be undertaken in order to dene all the air, water and

land pathways throgh which the varios contaminants

from the dened source terms may travel. This pathway

analysis shold be ndertaen sing an appropriatecompter code developed for this prpose and shold

inclde all pathway interactions which may reasonably

occr.

Tak C: unrtak tranport mong to

dene contaminant concentrations at critical

grop rcptor

Once the pathway analysis has been completed, the

transport of contaminants along these pathways will

need to be modelled. For example, for the atmospheric

pathway, the dispersion of particlate and gaseos

emissions will need to be modelled sing appropriate

compter codes in order to derive the concentration

of these contaminants at the critical receptor. Similarlyfor the srface and grond water rotes, taing into

accont other intermediate receptors sch as macro-

invertebrates, aqatic species, sediments, livestoc and

irrigated crops wherever appropriate. The otpt of this

task would be a specied concentration, duration and

probability of ey contaminants at the critical receptors.

Tak d: unrtak toxct amnt of

wat tram

With the information provided in Tass A, B and C, a

toxicity assessment can be undertaken to dene thedeleterios effects, if any, reslting from the varios

contaminants in the varios waste streams. Sch a

toxicity assessment mst be based on the methodologies

proposed by the Department of Water Affairs and will

focs on the potential maximm toxicity (the conservative

approach) of the waste streams and the mobility of the

contaminants into different environmental pathways.

Task E: Dene pathway-specic, contaminant-

specic and cumulative environmental risk to

crtca grop rcptor

Based on the toxicity assessment which were ndertaen

in Tas D and the pathways and transport modeling

undertaken in Tasks B and C, it will be possible to dene

the environmental riss for each contaminant or for each

pathway or cmlatively for all contribting ris factors.

This will enable later phases of the project to focs

remediation or design changes to those components

of the process train which directly contribte most

signicantly to the unacceptable risk which needs to

be addressed. In this way, the benecial effects of any

remediation measres can be rapidly assessed in terms

of real effect at the particlar receptor of interest.

stp 7: i rmaton rqr n trm

of stp 4, 5 an 6?

The environmental riss/impacts which are assessed

in Step 6 need to be evalated in terms of the indstry

norms and standards and the minimm legal/reglatory

requirements dened in Steps 4 and 5. The risks

shold also be evalated in terms of the assessed

consequence to the critical receptors as dened in Step

6. If unacceptable risks are identied, then appropriate




____________________________________________________________________________________________________________________________________

65

remediation measres will need to be evalated in terms

of modifying the existing design of the process plant.

Shold it be fond that no remediation is reqired, then

the existing process design will need to be evalated interms of monitoring systems to ensre that these are

adeqate.

Step 8: Dene and apply remediation

mar to proc gn

If the assessment in Step 7 indicates that nacceptable

environmental or legal riss are associated with the

proposed process as it is crrently engineered, then

appropriate remediation measures should be identied.

The correct place to apply the remediation measres will

be highlighted by the pathways and transport modelling

exercise ndertaen as part of Step 6. For example, it may

be decided to add a water treatment plant to the process

train to ensure that liquid efuent discharges pose no

signicant risk to the receiving environmental media, or it

may be decided to separate certain solid waste streams

and dispose of them nder tightly controlled conditions or

treat them to a less toxic form.

Step 9: Dene and apply monitoring

mar to proc gn

In order to ensre that the proposed process can

demonstrate to reglators and other interested and

affected parties that it poses no nde environmental ris,

it will be necessary to design, implement and maintain

an appropriate environmental monitoring programme.

This monitoring programme will also provide the plant

operators with the reqisite information for ensring that

appropriate management controls are applied at the

earliest possible stage. Even the best designed process

can have eqipment malfnctions and the monitoring

systems shold be designed to identify sch malfnctions

timeosly before serios environmental impacts are

cased. The monitoring programme which will incldeboth sorce and receptor monitors will also provide the

proof that the environmental ris/impact is acceptable.

stp 10: Prpar comprnv

environmental risk /impact prole

ocmnt for t proc

Detailed docmentation shold be prepared which

clearly describes the rigoros evalation process which

the proposed plant will have been sbjected to. The

environmental ris to the critical receptors for the different

evaluation scenarios should be clearly specied and the

reqired emission control and monitoring eqipment to

ensure acceptable risk should also be clearly dened.

The report shold also draw comparisons between the

proposed process plant and other similar operations in

terms of environmental ris/impact.




____________________________________________________________________________________________________________________________________

67

iTeM yes NO ReCOMMeNded ACTiON/

ReAsON

sTeP 3: Are details on the site and process provided?• Layouts, infrastructure and support services

• Environmental details in terms of particularly the water

environment and its sensitivity

• Process details

• Inputs including raw material/ore and other chemicals

• Water resources - availability, sustainability, variability etc

• Other resources – personnel, nances, infrastructure

• Waste details

• Water reticulation

• Monitoring programme

• Future planssTeP 4: Does a water and salt balance exist? The water and salt

balance shold state clear objectives, be reglarly pdated and

consider the different hydrological cycles. Refer to BPG G2: Water

and Salt Balances.

sTeP 5: Are details provided in terms of the mine/plant water users

and their water reqirements (qantity and qality), their sensitivity to

changes/variability and contaminants of concern (COC)?

sTeP 6: Is water se minimized? (Are water conservation strategies

therefore implemented?)

Is water of different qualities segregated and are there different

water management systems for each of these?

Are materials stored in an appropriate manner on site based on itsreactivity with water and the area in which it is sed?

Is there a specic water management system for areas with a high

contamination risk to prevent it from impacting on other water

management systems and other plant areas?

Is a storm water management system in place? Refer to BPG G1:

Storm Water Management .

Does the storm water management system ensre that clean water is

ept clean and released to the receiving environment?

Does the storm water management system ensre that contaminated

storm water is captred and contained?

Are spillages cleaned qicly and handled in an appropriatemanner?

Is equipment reglarly inspected and maintained?

Are housekeeping and water management practices sustainable

over the life-cycle of the mine/plant? See Chapter 4.

sTeP 7: Is the generation of contaminants minimized throgh

inpt optimization, polltion prevention and polltion redction at

sorce?

Are the water quality requirements for the mine/plant water users

established?

Are monitoring, maintenance, inspections and audits condcted?




____________________________________________________________________________________________________________________________________

iTeM yes NO ReCOMMeNded ACTiON/

ReAsON

sTeP 8: Is a water reuse and reclamation strategy implemented?Refer to BPG H3: Water Reuse and Reclamation and BPG H4:

Water Treatment . The water rese and reclamation strategy shold:

• Identify opportunities for water reuse and reclamation

• Indicate the benets of water reuse and reclamation

• Identify and consider all water sources available

• Attempt to minimize water intake, consumptive water use and

water losses

• Maximize water reuse and reclamation by providing mine/plant

water sers with the poorest water qality possible withot affecting

the process or prodct qality

• Optimize the water reticulation system• Consider the destiny of unused internal water sources in terms

of the water management hierarchy by considering treatment to

allow rese, alternative ses, otside sers, discharge/disposal.

• Consider the advantages of material or byproduct recovery

sTeP 9: Are process changes and cleaner technologies

considered for implementation?

What are the barriers preventing the implementation of cleaner

production and how are they overcome?

sTeP 10 an 11: Is an IWWMP , which considers and docments all

the above considerations and principles, in place?