eng mining july 2012

JULY 2012

Informed and in-depth editorial on the world mining industry

www.im-mining.com

SX-EW TECHNOLOGY

MINING CHEMICALS

MINE DESIGNSOFTWARE

POTASH EXTRACTION

OPERATION FOCUS:Pampalo and Geomin

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metso.com email: [email protected]

Booth 2839

CONTENTSJ U L Y 2 0 1 2

AROUND THE WORLD 3 The Leader 4 World Prospects 64 Forthcoming events IBC Classifieds

COVER: Aggreko

Banro Corporations Twangiza gold mine is located 45 km south-southwest of Bukavu in

the South Kivu Province of DRC, close to the Rwandan border. The mine began operating

in October 2011 and is expected to produce 120,000 oz of gold annually with an

expected mine life of seven to eight years from currently-defined reserves. The entire

Twangiza operation is powered via an 8 MW Aggreko power plant. Being located in an

area with no power infrastructure, the Aggreko solution was an excellent match for

Banros power requirements at Twangiza

www.aggreko-always-on.com

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8 GREAT MINES KIMBERLEY AND KOFFIEFONTEINJohn Chadwick examines Petra Diamonds otherSouth African operations of KimberleyUnderground, Koffiefontein and the Fissuremines.

13 OPERATION FOCUS PampaloJohn Chadwick reports from EndominesPampalo, one of the cleanest gold mines in theworld in the farthest east boundary of the EU,with expanding production likely.

20 OPERATION FOCUS GeominPaul Moore visited the specialist undergroundwhite marble mining operations of Geomin atHermsdorf in eastern Germany near the Czechborder, to see the companys mechanised miningfleet in action.

26 SX-EW TECHNOLOGYNew ideas, chemicals and technologies in theheap leaching world, John Chadwick takes alook.

34 MINING SOFTWAREReviewing mining software developments inmine design, scheduling and management, PaulMoore highlights the importance of functionalityacross the board, and some excitingdevelopments in the area of 3D visualisation.

48 MINING CHEMICALSJohn Chadwick looks at new products and trendsin a sector of growing importance, the globalmarket for which is projected to surpass $25.7billion by 2017

56 HIGH PROFILE AGGREKOPaul Moore spoke with Andy Walker, Head ofBusiness Development for Mining and Cementat global temporary power specialist Aggreko,about mining as an industry focus for thecompany.

58 POTASH EXTRACTIONPaul Moore looks at the ongoing hive of activityin the potash market, from both majors andjuniors, that is proving highly prospective for thekey shaft sinking groups, EPCMs and continuousmining machine manufacturers.

JULY 2012

Informed and in-depth editorial on the world mining industry

www.im-mining.com

SX-EW TECHNOLOGY

MINING CHEMICALSMINE DESIGNSOFTWARE

POTASH EXTRACTION

OPERATION FOCUS:Pampalo and Geomin

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ExcellentMiningSolutions

Weir Minerals. Working hard to keep you in the black.

There are all kinds of economic indicators you can talk about. In this business, the

only one that matters is a steady ow of coal coming out of the ground. Thats what

its all about. Thats what were all about. The idea is to build products better.

And back them better. That means genuine Weir Minerals replacement parts. And

real, live Weir Minerals engineering support, when and where you need it, anywhere

theres coal in the ground. What goes down when a pump or valve goes down? Pro-

ductivity. Which is why we put everything weve got into keeping you working. And

in the black.

Weir Minerals. Expertise where it counts.www.weirminerals.com/coal Copyright 2012, Weir Slurry Group, Inc. All rights reserved.

Following the publication of detailed articles

on advances in underground drilling, loading,

hauling and utility equipment in the June

issue of IM a report has just been released that

summarises the results of research conducted by

The Parker Bay Co and Raw Materials Group

(RMG). Market Analysis: Underground Mining

Equipment examines the market for underground

mobile mining equipment operating in hard rock

mines around the world. It covers the market for

wheel loaders/LHD's, mining trucks, drills

(development and production) and bolters.

Equipment population data is derived from an

Underground Mining Equipment Database (UGDb)

currently under development by Parker Bay and

RMG. Underground mineral production data is

taken from RMG databases covering metal and iron

ore production at mines worldwide. Initially this

database covers all countries except China.

Data from the UGDb is combined with estimates

for the global installed base for each product line.

These estimates were derived from figures

obtained from the primary manufacturers of the

underground mobile mining equipment covered by

this report and industry contacts, such as

International Mining, with knowledge of such data.

The numbers were further refined examining

RMGs underground mineral production figures.

The authors warn that the UGDb is judged to

identify approximately one third of the total

population of nearly 30,000 underground trucks,

LHDs, drills and bolters with a variation by product

line ranging from 17% to 37%. While the 9,000+

identified machines is a notable subset of data

from which to draw conclusions about the

population as a whole, it may not be statistically

representative due to greater availability of

sources of data for certain manufacturers, regions,

models, etc. The data comes from some 400

mines out of an estimated total of 1,000

underground mines in the world. They make no

guarantees of the accuracy of the information, but

have endeavored to provide a thorough, logical

analysis of available data.

Some 1,100 to 1,200 Mt of ore is extracted

annually from underground hard rock mines

around the world; 500 Mt is covered by mines with

machine data. While conventional, non-

mechanised methods are still widely employed in

certain parts of the world, underground mobile

mining equipment is the mainstay throughout

many regions and for the majority of the largest

operations, though its use varies depending on the

type of mine.

The report concludes, as was expected, that in

hard rock taking underground mobile mining

equipment as a whole,

Atlas Copco and Sandvik

are the clear market

leaders, each with more

than a third of the total

market. Caterpillar's

significant shares of the

LHD and truck markets,

make it the most viable third competitor with the

others being mostly regional and niche players.

Wheel loaders comprise the largest single

product group with nearly 11,000 units in operation

followed by trucks and development drills both at

around 7-8,000. Production drills and bolters have

far smaller installed bases, in the vicinity of 2,000

each. Sandvik is the leader in underground loading

and haulage equipment while trailing Atlas Copco

in drilling and bolting. Competition in these latter

categories is particularly scarce with the big two

approaching a 90% combined share compared to

about 2/3rds of LHDs. They account for about half

the worlds underground trucks between them.

Other loader and truck manufacturers covered

include GHH Fahrzeuge, Volvo, Zanam Legmet,

MTI, AARD, Fadroma, Dux, Bell, Getman, Maclean

and Russias MoAZ. Development drills included

MTI and Oldenburg. Production drill analysis also

took in Cubex and Boart Longyear. Maclean and

Mine Master. Each category included many others,

of smaller fleet numbers.

There is still vast untapped potential for

mechanisation, as the report notes. Despite being

the clear leader in underground mineral

production, Asia has the smallest equipment

population owing to both a large number of non-

mechanised mines as well the absence of an

accounting for indigenous suppliers (especially

China) among the known population. The most

notable inverse to this ratio being North America

and Oceania where mines account for far greater

shares of the worldwide equipment population

than global mineral production.

Africa is a region where mechanisation has far to

come yet. South Africa and Zambia account for

almost 90% of the underground market in Africa

with some underground mines in Zimbabwe,

Ghana and Mali providing much of the rest.

Many mines in Africa, particularly gold mines,

still use conventional mining methods with hand-

held drills and track-bound equipment. In contrast

to gold, PGM mines are mechanised to a higher

degree.

John Chadwick

Publisher

[email protected]

THE LEADER VOLU M E 8 N U M B E R 7

Much more mechanisation potential PublisherJohn ChadwickEmail: [email protected]

EditorPaul MooreEmail: [email protected]

Associate EditorChris CannEmail: [email protected]

Editorial BoardProfessor Malcolm ScobleRobert E. Hallbauer Chair in Mining Engineering., University of BC, Vancouver

Jeff RoschykVice President of Product Management & Marketing, P&H Mining, USA

Peter KnightsBMA Chair & Prof. of Mining Engineering University of Queensland

Stephen StoneWest One ManagementPerth, Western Australia

Dr. Andrew M. RobertsonPresident, Robertson GeoConsultants Vancouver, Canada.

Ed McCordProject ConsultantCaterpillar Global Mining, USA

Jason NitzMining Systems Strategist Newcrest Mining Ltd, Australia

Dr Terry MudderManaging DirectorTIMES Ltd, USA

Simon TarbuttConsultant, Santiago, Chile

Dr. Mike DanielComminution Process ConsultantAusenco Minerals & Metals, Australia

Editorial Enquiries:Tel: +44 (0)1442 870 829Fax +44 (0)1442 870 617

Advertising Sales:Phil PlayleEmail: [email protected]+44 1442 87 77 77

Advertising ProductionEmma SmithEmail: [email protected]

Publishing ConsultantRobin Peach

Design & ProductionTrevor SheldonEmail: [email protected]

Website:www.im-mining.com

Annual Subscription Enquiries:Emma SmithEmail: [email protected]

Annual SubscriptionUK and Europe 160, 230Rest of the world US$270

International Mining is published monthly by Team Publishing Ltd,2 Claridge Court, Lower Kings RoadBerkhamsted, Herts. HP4 2AF, UK

Printed by The Manson Group, St Albans

Team Publishing Ltd 2012ISSN 1747 -146X


WORLD PROSPECTS

4 International Mining | JULY 2012

When coal processing plants are anappreciable distance from the mine,how best to transport the coal from one

to the other is a key consideration, saysJonathan Cooksley, Sales and MarketingDirector, Twiflex. It is not unusual for theprocessing plant to be many kilometres away,which might at first glance suggest delivery bytruck. But overland conveyors can oftenprovide a far more economical solution,providing cost reductions in the order of 20-40%or more, he says.

Of course with a conveyor that may run for a

long distance, there are many designconsiderations to take into account; all of whichwill impact on long term reliability, availabilityand maintenance requirements. Transportingvast tonnages of coal overland, particularlywhere there are inclines involved, requires thehighest levels of expertise in sophisticatedconveyor and control systems.

One of the most important designconsiderations is the braking technology to beemployed, Cooksley says. Today Twiflex offersthe largest range of industrial disc brakes in theworld.

Disc brakes meet the requirements ofoverland coal conveyors in several areas. As wellas being the ideal technology for normalstopping and parking operations, they alsoprovide vital emergency stops. They are theideal choice where one conveyor feeds anotherand there is a risk of spill e.g. where theconveyor from a crusher at the mine feeds theoverland conveyor to the processing plant.

In normal operation, depending on theinstallation, the disc brakes may only be usedduring the final stages of braking, when they areapplied to lock the conveyor in its parkedposition. In other applications, they may beneeded to provide general slowing and stoppingduties. Most importantly, in the event of a powerfailure, the brakes will be required to stop andhold a fully loaded belt.

Twiflex specialises in Power Off brakingsystems. Powerful springs apply force tocompress the brake pads against the disc. Torelease the brakes the springs are compressedby a retraction device, which in overlandconveyor applications will typically behydraulically actuated. Any failure in the supplyto the retraction device would cause the springsto be released, so providing Power Off braking.

Twiflex braking systems are used on overlandcoal conveyors across the globe, but some ofthe most demanding of these are installed in theUSA. One example is a conveyor transporting165 t/h of coal on a 5 incline. Here, two spring-

Twiflex disc brakes meet overland conveyor needs

Twiflex GMR-SH spring applied, hydraulicreleased brake units fitted to a power stationconveyor in Victoria, Australia

Petra Diamonds the last Great Minesarticle on the company appears thismonth - has commissioned the rebuilt

plant at Williamson. In line with previousstatements, the company is revisiting thelonger-term 10 Mt/y expansion project. Thisproject will be dependent upon a secureelectricity supply, appropriate for the 10 Mt/yplant, and treatment results of main pit materialfollowing a six to nine month period ofproduction using the rebuilt plant processingfacility. This expanded output would yield some600,000 ct/y and take mining to a depth ofapproximately 260 m.

The following conditions are unique toWilliamson, Petra says: An immensely large resource located within

an open pit lending itself to economies ofscale

A low stripping ratio A soft ore that lends itself to AG milling The ore contains sufficient grinding material

in the form of granite.It was the confluence of these factors that led

Petra to put in place an appropriate expansionplan to 10 Mt/y, with a life of mine plan of 17

years, whilst targeting unit operating costs of$7.6/t. This will extract 170 Mt of the remaining986 Mt resource. Petra foresees a long life forthe operation, particularly since the orebodyremains open-ended at depth.

Williamson growth of Tanzanian diamonds

The tailings conveyorfrom the two-roll

Classifier at Williamson

The legends of hauling will be born soon. Stay tuned.Join the movement towards The Future of Mining.Its This Way: sandvik.com/thisway

Come and see us at

booth C-7309 Central Hall

FASTERHIGHERSTRONGERTHIS WAY!

Barrick Golds Pascua-Lama will be one of the highest altitude mines inthe world, at between 3,800 and 5,200 m above sea level. The average temperature through the year is 0C. Operating in these conditions is notnew to Barrick. Its Veladero mine, located 10 km away in Argentina, openedin 2005.

Each year it is expected to produce 800,000 - 850,000 ozof gold, and about 35 Moz of silver, in its first full five yearsof operation at negative cash costs of $225-275/oz. Forevery $1/oz increase in the silver price, total cash costs areexpected to decrease by about $35/oz over this period.

It has proven and probable reserves of 17.9 Moz of goldand 676 Moz of silver contained within reported goldresources, as of December 31, 2011.

The Chilean side of the mine (lower half of the overviewimage), will use conventional surface mining methods,including drilling, blasting and hauling by truck to anadjacent crushing facility. Ore will be transportedunderground by conveyor through a 4 km tunnel to theprocess plant facility, on the Argentine side of the mine.

Looking down on the project site, the platform for theprimary crusher is seen on the right. The portal of the tunnelthat will take ore for processing on the Argentine side canbe seen on the left.

The other picture shows a Komatsu haul truck draped inthe flags of Argentina and Chile rolling out of the open pitstaging area as employees look on. Pascua-Lama will be anopen pit operation producing both refractory andnon-refractory ore. The mining fleet will include 30 largehaul trucks like this, five shovels and three loaders.

WORLD PROSPECTS


applied, hydraulically released VKSD type discbrakes are used, acting on 25.4 mm thick discs,1,067 mm in diameter, to provide 104,000 Nm ofbraking torque. The VKSD is part of Twiflexsmodular series and is a standard two-moduledesign, with the brake provided as standardwith two pre-fitted brake pads. The brakes weresupplied complete with an electro-hydraulicpower pack with provision for variabledeceleration control.

Bucim mine, Macedonia has an example of alonger conveyor that runs to 2,696 m long,carrying some 5,180 t/h. Here two VKSD discbrakes act on 38 mm thick discs of 1,220 mmdiameter, providing 60,300 Nm of brakingtorque. The brakes were supplied complete withan electro-hydraulic power pack with theprovision for soft braking.

In a more demanding installation in the US,VKSD disc brakes are used to provide 295,000Nm of braking torque on an overland coalconveyor for Bowie Resources, Colorado. Theconveyor carries a 1,500 t/h along an 840-mconveyor with a 13.25 decline. The two VKSDbrakes act on 38 mm thick discs of 1,422 mmdiameter.

At an installation for Mulzer Crushed Stone,Indiana, an overland conveyor carries 1,100 t/hover 87 m at a 5 incline. Here Twiflexrecommended the MXSH series disc brakes,which feature a patented, compliant linkmechanism to ensure uniform pad wear. The twobrakes act on 38 mm thick discs of 610 mmdiameter, providing 5,965 Nm of braking torque.The supplied LC electro-hydraulic power packoffered provision for fast approach and variable

deceleration control. LC power packs provide arange of standalone units with options for softbraking, a range of operating and motorvoltages, and various add-on accessoriesincluding a terminal box.

On an installation for Cripple Creek and VictorGold, Colorado, requiring 47,450 Nm of brakingtorque, Twiflex recommended a GMRSH typedisc brake acting on a 25.4 mm thick 72 mmdiameter disc. These brakes were supplied witha Twiflex MP electro-hydraulic power pack withprovision for fast approach and decelerationcontrol. MP series power packs have beendesigned to provide an advanced and flexiblemeans of brake control and to operate under themost arduous conditions where the environmentis extreme but reliable operation all year roundis paramount. www.twiflex.com

B i n a t i o n a l P a s c u a L a m a t a k i n g s h a p e

Introducing an almost magical drilling system

Were not known for dabbling in make-believe. In fact, few things are more real than the benefits thatcome with our new T-thread. Especially when you consider that large rods require a robust thread system.

The new T-WiZ drill string looks a lot like its predecessor, but thats where the similarities end. Were notabout to reveal all our tricks, but youll be amazed to know that T-WiZ offers up to 30% longer service life.Which means fewer rod changes and more productivity per shift.

So test the combination of T-WiZ Speedrods with T-WiZ shank adapters the benefits are spectacular.

Atlas Copco Secoroc ABBox 521, SE-737 25 Fagersta, SwedenPhone: +46 223 461 00E-mail: [email protected]

The companys two large underground

mines of Cullinan (May 2012, pp8-15) and

Finsch (June 2012, pp10-13) have already

been covered. Kimberley is the other very

emotive name in the stable. Here at the home of

diamond mining, Kimberley Underground

comprises three kimberlite pipe mines in close

proximity: Bultfontein (10 ha at surface),

Dutoitspan (11 ha) and Wesselton (9 ha). These

mines were integral to the economic

development of South Africa as their output

effectively financed development of the nascent

gold industry. They are currently mining at

depths of between 845 and 995 m below surface.

They have a history of producing large

diamonds and fancy yellows, such as the

Oppenheimer (253 ct rough and the Kimberley

Octahedral (616 ct rough).

Petras expansion plan at Kimberley

Underground envisages production rising from

about 57,000 ct in FY 2011 to some 120,000 ct/y

by FY 2013. Total resources (inclusive of

reserves) amount to 7.1 Mct, to a currently

known depth of 1,060 m. All three employ block

caving at current depths of 845 m (Bultfontein),

870 m (Dutoitspan) and 995 m (Wesselton).

Bultfontein is mined using a slusher drift block

cave mining method simultaneously with the rim

loading section. The Dutoitspan and Wesselton

mines employ a slusher drift block caving

method.

FY 2011 marked the first full year for

Kimberley Underground under Petra

management, following completion of the

acquisition in May 2010. There was

encouragement in the prices achieved for its

production, with the average of $333/ct for the

period considerably exceeding initial

expectations.

At the new Joint Shaft plant, which services

the Bultfontein and Dutoitspan pipes, Petra

experienced some initial difficulties relating to

slimes and tailings disposal. To deal with the

high percentage of fines material inherent in the

Bultfontein and Dutoitspan ROM ore, Petra

introduced a scrubber into the processing

circuit, and is also introducing an apron feeder

to handle material with a high level of mud

content. It is anticipated that these measures

will ensure adequate fines removal and increase

throughput. The company has built up a ROM

stockpile at surface, estimated to be 0.4 Mt in

size, which gives flexibility to make up some of

the lower recent production levels by processing

higher tonnages once the plant throughput

issues have been overcome.

The plan for processing at Wesselton involves

a combination of a mobile pan plant together

with a new plant (similar to that constructed at

Joint Shaft). The new main plant at Kimberley

remains on track for commissioning in Q4 FY

2012.

Unit costs of approximately R191/t in FY 2011

were negatively impacted by reduced

throughput. These costs were expected to

John Chadwick examinesPetra Diamonds otherSouth African operations of Kimberley Underground,Kofefontein and theFissure mines

Kimberley and moreGREAT MINES


Kimberley underground mines

De Beers' Kimberley processing plant thatcontinues to recover diamonds from the tailingsdumps

The new Becker Mining Systems Belt Rip Detection System BRS 2 has been developed to help increase the

productivity of conveyor belts by detecting belt rips as soon and as reliable as possible. To monitor steel cable and

fibre belts, inductive loops need to be embedded in the belt. Once installed, the BRS 2 will detect the loops on

the conveyor, define and number the loops and create its own image of the belt and its loops in real time. The BRS 2

using its real time loop diagnostics, continuously monitors the belts health and in the event of a rip, stops the belt

and reduces any further damage and downtime. Access and the monitoring of the system is simple, either locally

with its 12TFT screen, 5 shortcut buttons, mouse pad and virtual keypad or remotely via TCP/IP or Modbus. An IS

version of the BRS is also available.

For more information please contact [email protected] or go to www.becker-mining.com

know-how performance reliability

becker. keeping your lifeline flowing.

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improve once the Wesselton plant is fully

operational.

Of the $13 million capex in FY 2011,

approximately $9.5 million was spent on

improvements to the Joint Shaft treatment plant.

A further $3.5 million was applied to the

acquisition of adjacent land, buildings and

infrastructure relating to water reticulation and

slimes handling facilities (by assuming a

rehabilitation guarantee).

Kimberley Underground has a current mine

plan of 11 years, which could be extended as

Petra more thoroughly investigates the

resources of these mines at depth and the East

Blow at surface.

De Beers continues to manage its surface

mining (tailings recovery) at Kimberley, which

operates independently of the underground

mine workings. It has a custom-built recovery

plant developed to efficiently treat and to

recover diamonds which produces some

400,000 ct/month. De Beers expects Kimberley

diamond recovery operations to continue

through 2023.

Expanding KoffiefonteinKoffiefontein (11 ha pipe at surface) is one of the

worlds top diamond mines by average value per

carat and produces exceptional white and

coloured diamonds, a regular proportion of

which are of between 5 and 30 ct. Underground

mining of the high value, low-grade

Koffiefontein kimberlite pipe is supplemented

by tailings treatment from a 65 Mt tailings

deposit and open-pit mining of the 5 ha satellite

pipe named Ebenhaezer.

Total resources (inclusive of reserves) amount

to 6.1 Mct, to a current depth of 690 m, though

the orebody remains open-ended at depth. The

current mining method is front cave, currently at

a depth of 490 m. The mine plan is for 14 years

but the potential life could be more than 20

years.

Koffiefontein achieved an average value per

carat of $564 for FY 2011, up 40% on the

comparative period despite the overall average

being reduced to some extent by a higher

proportion of lower value tailings production in

the total sales mix. ROM production for the year

was 35,139 ct (H1 FY 2011: 27,390 ct; H2 FY

2011: 7,749 ct). Tailings production was 12,817 ct

for the period (H1 FY 2011: 7,110 ct; H2 FY 2011:

5,707 ct). Capex of $11 million for FY 2011 was

mostly spent on underground development and

mining equipment.

Waste ingress and reduced production from

52 level significantly affected the ROM grade

(3.1 ct/100 t in H2 FY 2011 as compared to 5.9

ct/100 t in H1 FY 2011). As at Cullinan and

Finsch, Petras development plan at

Koffiefontein will establish new production

levels where the company will eventually have

access to undiluted ore. Once this has been

achieved, Petra expects the overall ROM grade

at Koffiefontein to improve to about 8 ct/100 t,

but it is expected that lower ROM grades could

be reported until FY 2014.

Extensive stress modelling simulations have

indicated that the planned front cave at the 580

m level be changed to a sub-level cave mining

method between the 560 and 600 m elevations.

It is expected that this plan will be executed

within the original timetable and capex

forecasts, with annual production expected to

reach 1 Mt/y in approximately three years and

reach 1.2 Mt/y in about five years, delivering

over 100,000 ct/y (ROM and tailings) by

FY 2017.


GREAT MINES

Kimberley Underground Mining overview

Joint Shaft plant re-crush circuit at KimberleyUnderground a plant assistant cleaning thecrusher sizing screen

Koffiefontein Mining overview

The Niagara is the defi nitive scalping screen; its classic, but far from ordinary. The single eccentric shaft guarantees constant circular motion and consistent G-force, even under extreme conditions. Clean openings in sticky situations. Feed sizes up to 80 x 40 x 40. Process reliability for surges under load. Dynamically balanced to minimize structural vibration. FAR FROM ORDINARY. INGENIOUSLY ECCENTRIC. THE NIAGARA.

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GREAT MINES

Different FissuresThe Fissure Mines consist of three mines Helam,

Sedibeng and Star which are unusual mines in

that the diamonds are extracted from kimberlite

dykes and not pipes. Northland Capital noted in

its report on Petra of March 8, 2012 that dykes

are narrower and more difficult to mine

and as a result, the mining cost per

tonne is around seven times that of a

kimberlite pipe. This financial year

(2012), Petra is expected to produce 2.2

Mct over all its operations, an increase

of 100% on last year. The Fissures will

contribute around 5% of the total

carats and 8% of revenue generated

this year. As Petra continues to expand

its production to just under 4 Mct by

2014, the Fissures contribution will

drop to 3% of the total carats produced

and 4% of the revenue.

The Sedibeng operation is an

amalgamation of two mines: Messina

and Dancarl. The mines are operating

at depths of between 600 and 750 m.

Plans to increase production from just

over 87,000 ct in FY 2011 to 140,000

ct/y by FY 2015 are currently being

implemented.

The strike lengths of the fissures at surface

are 6 km at Helam (depth of current mining 750

m), 2.4 km at Sedibeng (750 m) and 4.5 km at

Star (620 m). Helam and Sedibeng employ full

shrinkage overhand stoping, while Star is an

open stope underhand operation.

Helam and Sedibeng put in a strong

performance in FY 2011, with revenue for the

Fissures unit as a whole up 62% to $21.8 million

and overall production up 18% to 87,488 ct. The

average value per carat achieved also increased

32% to $244. For FY 2012, Petra expects a

similar level of combined production across the

fissure portfolio to FY 2011.

At Star, where operations are challenging, a

disappointing performance was recorded for the

year, as reflected in the impairment charge

incurred, Petra reported.

Unit costs for the Fissures remain flat despite

cost pressures specifically relating to electricity

and labour. The majority of the $5.2 million

capex in FY 2011 was spent on continuing

underground development across the fissure

mines including a headgear installation at

Sedibengs Dancarl shaft.

Additionally, $11.0 million was spent in

respect of the Helam projects manufacturing

facility for equipment under construction for

other mines and projects within the Group.

Northland Capital further reported that the

Fissure mines have a total resource of just under

5 Mct with an average diamond value of

$255/ct. The large amount of maintenance

capex spent by Petra from 2009 to 2011 has

ensured that the mines will continue to produce

at their current rate with a low maintenance

capex for years to come. IM


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Endomines Pampalo gold mine is currently

producing gold at an annualised rate of

800-900 kg. The mine is located on the 40

km-long gold-critical Karelian Gold Line, where

Endomines controls all currently known gold

deposits. The mine project was completed in

December 2010, on schedule and in line with the

budget at 20 million. Commercial production

commenced in February 2011 as scheduled.

The Pampalo deposit, which remains open at

depth, is located in the central part of the

Karelian Gold Line, 5 km north of the village

Hattuvaara. It is an Archean orogenic gold

deposit in an intermediate pyroclastic unit,

metamorphosed to greenschist - lower-

amphibolite facies. It lies close to the border

with Russia in the most easterly extremity of the

European Union.

Plant capacity was increased from 230,000

t/y to 270,000 t/y by debottlenecking during

2011. Metallurgical testing demonstrated that

the gold could be very efficiently extracted by

gravimetric separation and flotation

concentration. The best results indicated a

recovery of more than 90%. As a result, this

mine is very clean with minimal emissions, and

none to the environment. Its tailings facility is

full of what is effectively potable water.

No cyanide or acid is used and there is

nothing harmful in the tailings. There is no Acid

Mine Drainage (AMD). The target is for 100 %

water recirculation.

Like so many of the mines coming on stream

in Finland today, Pampalo is a former project of

Outokumpu. It was discovered in 1990 by the

Geological Survey of Finland and Outokumpu

Mining undertook intensive exploration and test

mining. Outokumpu carried out test mining first

in 1996, as an open pit. Later in 1998-1999 there

was limited underground mining down to a

depth of some 100 m. As a result, Endomines

came into the fortunate position of taking on a

well-developed decline to more than 250 m

below surface. Currently stoping is around the

220 m level and the decline today extends to

365 m below surface, to facilitate Pampalo

Deeps exploration.

Outokumpu hauled the ore it extracted by

road 400 km to both Vammala and Pyhsalmi for

beneficiation. A total

of 114,372 t was

mined, at an average

gold grade of 15.3 g/t,

producing 1,755 kg of

gold. Outokumpu ceased activities in 1999 and

Pampalo was acquired by Dragon Mining.

Endomines was established in 1996 as a

private company. It was registered at

Hattuvaara, Ilomantsi, and explored north from

Pampalo in 1996-2006, acquiring Pampalo in

2006.

Developing mining skillsFinland has an effective and somewhat unique

way of addressing skills shortages in mining,

through a national training institute. In North

Karelia this is Pohjois-Karjalan aikuisopisto

(PKKY) with colleges in Joensuu, Kitee, Lieksa,

Karelian gold

John Chadwick reports from one ofthe cleanest gold mines in the worldin the farthest east boundary of the

EU, with expanding production likely

Mucking by remote control. Picture by Eija Hiltunen

3D image of the threelenses of the Pampalodeposit. The sectionviewed fromnorthwest. The goldmineralisation isshown in differentcolours. The colourslight blue and red =existing declines,brown = open pit

OPERATION FOCUS


Niittylahti, Nurmes and Outokumpu. The latter is

the countrys primary centre for learning mining

skills.

Pohjois-Karjalan aikuisopisto (see box) has

been a very important contributor to the

successful development of Finlands latest two

mines, Pampalo and Altona Minings Kylylahti

(article in the September MINExpo, issue), both

officially opened on that same day, May 25, a

year apart; Pampalo in 2011 and Kylylahti this

year.

At Pampalo PKKY is not only providing

training but also contracting services.

Endomines has a Sandvik DD420-S60C twin

boom jumbo that together with PKKYs twin-

boom Atlas Copco Boomer E2.drills all the

development drifts to open up the stopes.

In this case, PKKY is working as a contractor

and is also training drill operators for

Endomines and other mining companies.

Pampalo also has PKKYs Sandviks DS410 rock

bolter and its Normet MC 605 DA Anfo charger

working under contract and providing training in

an active mine. At this stage the contract for

these machines ends at

the end of 2012.

Pampalo mining plan

is a design for sublevel

bench cut-and-fill

stoping (a modified

Avoca mining method)

with 14 m stope heights

in the upper levels and

17-20 m stope heights

in the lower levels. The

lower stope height

incurs higher stoping

costs per tonne of ore

but has lower costs in

consideration of rock reinforcement. In the

future, stoping will move to the deepest level to

minimise the losses of ore in horizontal pillars.

The choice of method was made to minimise

the extent of hanging wall exposure during

mining. The grade of the deposit prevents the

use of higher cost cut-and-fill mining methods,

which require cemented fill. This method allows

simultaneous mining and filling of the stopes to

minimise the span of the hanging wall exposed,

reducing the potential for hanging wall

instability and dilution.

The longhole drilling rig is a Sandvik DL430-C.

It is a narrow orebody, 4-10 m wide. Cable

bolting is the primary stope support method,

using a Sandvik DS420-C cable bolting rig. Janne

Muttonen, Resident Manager, is very happy with

this rig. He explained that it is used to install 6-

8 m cable bolts and can easily average more

than 100 m of cable bolting in a ten-hour shift.

Stopes are mucked out by Endomines

Sandvik LH 514 LHD, which load into a

contractors fleet of SISU and Scania trucks (20-

30 t) capacity for the haul to surface.

A Forcit MA 22 emulsion charger mounted on

a Scania P340 truck chassis. Kemiitti 810 is a

site sensitised pumpable emulsion explosive

developed by Forcit for underground mining. The

equipment on the truck automatically adjusts

the degree of charging in the boreholes suitable

for all. It carries all the equipment needed: the

detonators, ignition and emulsion needed for

producing Kemiitti 810. When charging, the

emulsion is converted into the explosive only

within the borehole.

Green goldThis April, Endomines decided to proceed with

increasing production capacity at Pampalo up to

a maximum of 450,000 t/y. The decision was

based on the results of a recent feasibility study.

A second-hand refurbished mill was acquired

before the end of last year, and this will now

OPERATION FOCUS


Sandvik DL430-C being used on this occasionfor sludge drilling and sampling to define theorebody in an area where only limited coredrilling has been undertaken.Picture by Eija Hiltunen

PKKYs Normet charger. Picture by Eija Hiltunen

A Forcit MA 22 emulsion charger mounted on aScania P340 truck chassis. Kemiitti 810 is a sitesensitised pumpable emulsion explosivedeveloped by Forcit for underground mining.The equipment on the truck automaticallyadjusts the degree of charging in the boreholessuitable for all. It carries all the equipmentneeded: the detonators, ignition and emulsionneeded for producing Kemiitti 810. Whencharging, the emulsion is converted into theexplosive only within the borehole.

This Sandvik DS420-C cable bolter is a popularand effective rig

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Imagine enhancing your recovery of scarce, valuable mineral resources

Visit us at Hydroprocess 2012 July 12-13,Santiago de Chile, Chile

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G11

27e

allow for a rapid capacity increase. An

environmental permit application for the

capacity increase was filed, and a decision is

expected early next year. Preparations are

underway with a view to starting test production

at Rmepuro, which is likely to be the first

satellite deposit to be developed. In addition to

the second mill, more flotation cells will be

added.

The plant expansion will allow for low grade,

currently uneconomic, open-pit mineral

resources to be converted to ore reserves which

can be mined and processed at Pampalo. It will

also ease problems with fine crushing.

The first thing that strikes you when entering

the plant from the control room is the shaking

tables. It is rare to see the gravimetric section of

a plant so prominent, but it is a very key part of

this facility. The 4,000 t/y of flotation

concentrate assays 100-250 g/t Au, and the rest

comes from the gravity circuit, recovering 30-

60% of the gold, depending on the ore being

treated at any time.

The crushing section

of the operation

comprises one jaw

crusher and two cone

crushers, delivering a 0-

13 mm product to the

mill. Metso designed

the plant and provided

much of the equipment,

including a Metso TRN

3.0 x 4.8 m wet ball mill

with grate discharge. It

is equipped with an

800 kW ABB motor. The

ore is ground to a P80

of >75 m. There are

six Metso RCS20 flotation cells and one Metso

RCS 3 cell. There is also a Metso CT SFL10 - 5

thickener. Hannu Tahvanainen, Mill

Superintendent, finds the plants Numcore

Flotation Watch system very effective. This is a

froth flotation process control solution, recently

acquired by Outotec that simply increases

recovery without contamination problems. By

using 3D-imaging, the solution provides

accurate, online information on froth stiffness

and thickness of the froth bed. These froth

properties can then be controlled by automatic

adjustment of chemicals and frothers.

The first cyclone cluster comprises a Multotec

distributor: D3-25/3 and Multotec cyclones:

HC250-L10-1/A-A/60, fitted with a 100 mm

vortex finder and 60 mm spigot. Another cyclone

cluster comprises a Multotec D2-42/2

distributor and HC420-30-0/A-A/110 cyclones,

fitted with a 185 mm vortex finder and 110 mm

spigot. And the third has a D2-35/2 Multotec

distributor and HC350-15-0/A-B/45 cyclones

fitted with a 111 mm vortex finder and 45 mm

spigot. Cyclone overflow goes to flotation and

the underflow to the spirals and tables.

The gravity spirals were supplied by Downer

EDI Mining - one bank of 12 Tripple-start LG7s.

There are two Deister single-deck No6 2 kW

shaking tables. One is left handed and one right

handed.

In May Endomines AB signed an agreement to

sell and deliver its gravimetric gold concentrate

production from Pampalo to precious metals

refiner K.A. Rasmussen AS, Norway. The volume

of deliveries and estimated concentrate grade

allow up to 100% of gravimetric concentrate

production to be delivered to Rasmussen. The

agreement is signed for a period of one year,

with the option of renewal for successive one

year periods.

Markus Ekberg, CEO of Endomines

commented that "commercial test deliveries

have proven to be mutually satisfactory. The

agreement provides Endomines with flexibility,

as it can balance its production between higher

value gravimetric gold concentrate and flotation

concentrate production volumes."

OPERATION FOCUS


Alimak raise miner in action.Picture by Eija Hiltunen

Feeder

Crusher ore stockpile

Trucking

Grinidng mill

Classification

Gravimteric

circuit

Flotaition

Gravimetric concentrate

Grade 30-50 % Au

Flotation concentarte

~4-6 000 t/a; 100-200 g/t Au

Coarse fraction

Fines

Tailings Storage Facility

Mine Drainage

Water

New grinding mill

Additonal flotation volume

Classification

Crusher

No cyanide or acid used

No harmful material in tailings

No Acid Mine Drainage (AMD)

Target 100 % water recirculationThe plant was designed for expansionfrom the outset

Pampalo is a very clean operation - waterbalance for the expanded mill capacity of450,000 t/y

Endomines is the leading partner in the

TEKES Green Mining Project, Responsible

Gold together with JOSEK, Outotec and GAIA-

consulting. Stage 1 is evaluating possibilities to

produce traceable, responsible gold using

Endomines gold as a raw material and was to be

completed by August 2012. Stage 2 will develop

a prefeasibility study and investor plan, with the

final investment plan established in Stage 3.

Line of gold on one of the Deister shakingtables

OPERATION FOCUS


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Finlands great mining skills training facility

Pohjois-Karjalan aikuisopisto (www.pkky.fi North Karelia Municipal Education and TrainingConsortium) is the organisation whose main function is to provide qualified vocational educationin the county of North Karelia. Each year some 1,600 students, both young people and adults,obtain a vocational qualification at its institutes. It is owned by all 14 of the county's municipalities.

One of its strengths lies in effective cooperation; intercommunication between the College, the

Adult Education Centre and the Upper Secondary Schools in the region as well as the North Karelia

Polytechnic and, in the case of mining at Outokumpu, close ties with the industry itself. National

indicators show that it is among the elite of Finnish education providers.

There are 20 educators specialising in training mining technologies attached to the Outokumpu

college. The primary mining courses cover explosives and blasting, mining technology, mine

development and mineral processing. The college also co-operates with GTK, the Geological Survey

of Finland, for rock sampling education and training.

The standard courses in after-training, retraining adults to work in mining, cover underground or

surface mining and mineral processing and most of the work is tailored to specific client mining

company needs. Maintaining and improving adult learning skills, it takes one year to qualify half

the time being spent on theory and half practical.

In addition to the three machines at Pampalo, the college has two other Sandvik drill rigs a DX 780 and

a CHA 560 and two small Commando rigs. There is also a surface drill

simulator a Sandvik DP1500i.

The institute intends also to buy an LHD, an emulsion charger,

haul trucks and an underground drill simulator. The aim is always to

have new equipment on which operators can train, so each unit in

the fleet will be replaced within five years.

The most important types of education are vocational education

and training (upper secondary level), adult education, vocational

further and supplementary education and training, labour policy

education, apprenticeship training, common non-vocational

education, and summer university teaching.

Along the Gold LineEkberg points to the similarities and the

analogous Archaen geology in Ilomantsi (no

gold mines in production in 2009) and the

Southern Cross greenstone belt in Australia. The

latter had four mines in production in 2009, and

more than 40 had been closed over the time the

belt has been producing:

Endomines estimates its properties currently

hold Proven and Probable ore reserves of 1.6 Mt

with an average gold grade of 3.5 g/t, with

exploration producing promising results all the

time. These reserves and resources are all

located along the Karelian Gold Line - 120,000

oz in Pampalo and 60,000 oz in deposits close

to Pampalo with resources open for

expansion. All satellites along the Gold Line are

within trucking distance of the Pampalo plant.

The Karelian Gold Line comprises more than

40 km of gold mineralisation with excellent

potential in Archean rocks. Endomines holds

400 km2 in claims and reservations, including

23 known gold showings. It has been granted

two mining concessions to date and five more

are under application. An EIA (Environmental

Impact Assessment) for the entire area is

ongoing. A total of 65 new claim applications

have been lodged and exploration is ongoing at

a good pace.

Pampalo underground diamond drilling

commenced early this year and surface diamond

drilling there began in May. Korvilansuo is the

main target in 2012, along with Rmepuro

drilling, where pilot plant process testing is

underway. The total 2012 drilling target is 8,000

to 10,000 m.

A combination of Endomines clean credentials

and the otherwise generally poor employment

opportunities in North Karelia mean the

company is welcomed wherever it goes.

At the end of May,

Endomines reported

preliminary results from its

current underground core

drilling campaign at the

Pampalo mine. Results

were received from the

first seven holes of a 15-

hole, 739-m, campaign,

which started in April

2012. This campaign

focused on an area

between the Pampalo and

Pampalo East ore zones,

and yielded a number of

encouraging intercepts,

including 6 m @ 5.9 g/t Au, 12.6 m @ 5.2 g/t,

and 9.8 m @ 5.0 g/t Au, in addition to the

previously drilled intercepts yielding 9.2 m @ 4.1

g/t Au and 11.6 m @ 3.2 g/t Au.

The company says these results prove that

there is a previously unknown mineralised zone

between the currently known Pampalo and

Pampalo East gold resources, at grades

comparable with the previously known gold

lodes at Pampalo. The drilling campaign will

proceed further as planned upwards, down dip

and along strike with a view to follow the

mineralised zone.

These exploration results from the first

exploration drillings in 2012 have confirmed the

significant potential for further gold deposits in

the immediate vicinity of the Pampalo ore, said

Markus Ekberg, CEO of Endomines. IM


OPERATION FOCUS

Parameter Ilomantsi (Karelian Gold Line) Southern Cross

Belt length 90 km 110 km

Belt width 0.510 km 0.515 km

Gold exploration since 1986 1888

Total gold produced 55,000 oz >10 Moz

Known reserves & resources 450,000 >2 Moz

Gold ore reserves - Karelian Gold Line 31st Dec 2011

Deposit TonnesGrade

Au g/tOz kg Classification Consultant

Pampalo 10 000 3,0 965 30 Stockpiled Endomines

662 000 3,4 72 146 2 244 Proven Outotec Oyj

426 000 2,7 36 748 1 143 Probable Outotec Oyj

SubTotal 1 098 000 3,1 109 859 3 417

Pampalo East 200 000 1,5 9 645 300 Probable MAPTEK

Pampalo Reserves total 1 298 000 2,9 119 504 3 717

Hosko 13 000 8,5 3 553 111 Proven MAPTEK

116 000 10,0 37 295 1 160 Probable MAPTEK

Hosko total 129 000 9,9 40 848 1 271

Rmepuro 134 000 3,9 16 802 523 Probable MAPTEK

Muurinsuo 67 000 3,0 6 462 201 Probable MAPTEK

Grand total 1 628 000 3,5 183 616 5 711

Mineral Resources Karelian Gold Line 31st Dec 2011

Deposit TonnesGrade

Au g/tOz kg Classification Consultant

Pampalo 130 000 3,5 14 629 455 Inferred Outotec Oyj

Pampalo East 21 000 1,5 1 013 32 Inferred Runge Limited

Hosko 547 000 1,8 31 656 985 Inferred Runge Limited

Rmepuro 61 000 4,1 8 041 250 Inferred Runge Limited

Muurinsuo 786 000 1,5 37 906 1 179 Inferred Runge Limited

Kuivisto East 37 000 3,2 3 807 118 Indicated Kuivisto East 145 000 1,0 4 662 145 Inferred Kuittila 275 000 2,6 22 988 715 Inferred GSF, historical

Grand total 2 002 000 1,9 124 700 3 879

The Karelian Gold Line

Diamond drilling contractor Drillcon SMOYoperating a new Sandvik core drill, mounted ona mini-excavator crawler chassis, undergroundat Pampalo

IT STARTS WITH A SINGULAR FOCUSAt Joy Global, were combining resources to better serve our customers worldwide. With a direct service approach dedicated to one thing and only one thing: mining performance.

The Hermsdorf mine is one of two mines

operated by specialist industrial minerals

group, Geomin Erzgebirgische Kalkwerke,

the second one being Lengefeld. The company

also has a third mine under development,

Hammerunterwiesenthal, for which it is

currently assessing fleet options.

The underground mine exploits calcitic

marble from a deposit located in the eastern

Erzgebirge (literally, Ore Mountains) to the

southwest of the village of Hermsdorf. The first

documented mention of marble production

dates back to the year 1581. At that time the

marble was widely used as a building material

and for decorative sculpture. The underground

activities started in 1880 in the Fiskalischer

Bruch (Fiscal Quarry), when production was

mainly a raw material for quicklime production,

which was used mainly in agriculture and in the

steel industry.

Geology and formationThe age of the marble deposit at Hermsdorf is

still debated. Lithostratigraphically, the thick

sequence of interlayered marble and phyllite is

ascribed to the Herold Formation as part of the

Thum Group. This would correspond to a

Cambrian age of approximately 510 million

years. The deposit is situated in the upper

Herold Formation.

The underlying rocks of the deposit are

Precambrian gneisses of the Prenitz Group and

Proterzoic metagranitoids as well as Cambrian

lithologic equivalents of the Breitenbrunn

Formation (muscovite schists). Besides these

originally late Cadomian igneous rocks and their

subsequent prograde metamorphism, the

footwall of the marble unit (quartz-rich phyllites

and hornblende-chlorite schists of the lower

Herold Formation) represents originally

submarine basic volcanic rocks subsequently

affected by retrograde greenschist-facies

metamorphism.

The deposit comprises six calcitic white

marble horizons (k0, k2-k5) and one grey

horizon (k1). The marble is thought to have a

marine sedimentary protolith. The carbonate

sedimentation took place under turbulent

conditions. One reason for

this interpretation is the

rough surface relief of horizon

k0 (the deepest marble

occurrence in the deposit)

with high variations in

thickness and parallel

splitting into several marble

layers. These observations

suggest a rapid change of

depositional conditions. The

k1 horizon is characterised by

similar but more distinct

features. In the former about 30-40 m thick reef

limestones act as cores of tectonically

developed horst structures. In contrast, the k1

horizon has partly been downthrown at

synsedimentary graben-like structures.

Such deep sedimentation basins provided the

environment for the development of four white

marble horizons (k2-k5) with changing facial

features and varying thickness. Caused by post-

metamorphic brittle tectonic deformation, the

white marble horizons were divided into fault-

bound separated blocks being tilted and

thrusted between the horst structures.

The tectonic features of the deposit are of

particular importance. The main foliation of the

wall rocks forms a girdle fabric with axes

Whiter than white

Paul Moore visited the specialistunderground white marble mining

operations of Geomin at Hermsdorf ineastern Germany near the Czech

border, to see the companysmechanised mining eet in action

OPERATION FOCUS


The ST7, here loading Geomincalcitic marble at Hermsdorf mine,features high fuel efficiency andimproved safety attributes

ST7 operator at Hermsdorf,Dirk Thiele

Thanks.

J.H. Fletcher & Co.402 High Street

Huntington,WV 25705304.525.7811

www.jhfletcher.com

For seventy-five years, J.H. Fletcher & Co. has dedicated itself to the improvement of operator safety

and productivity in the worlds underground mines.For our success, we thank our employees, customers,

suppliers, family and friends.

Booth 2615Scan this code to visit

our website

Seventy-five years. And this is just the beginning.

2012 J.H. Fletcher & Co. All rights reserved.

striking E-W. Large SW-NE trending fault zones,

which are thought to be related with Upper

Carboniferous post-kinematic volcanic activity,

divide the phyllites of Hermsdorf into several

blocks with displacements of up to 40 m. The

central part of these blocks has been

downthrown as a graben and covered with

rhyolites, which preserved the upper Herold

Formation (including the marble deposit) from

erosion.

The white marble from Hermsdorf dominantly

consists of calcite with variable but low contents

of quartz and phyllosilicates. The metamorphic

foliation is traced by oriented crystals of quartz,

chlorite and white mica as well as by grain size

variations of the calcites resulting in a banded

marble structure. The marble is free of bacterial

and organic components and does not contain

any graphitic inclusions.

Mining method summaryThe mining activities comprise mining of

residual marble occurrences in older parts of the

mine and the contemporaneous exploitation of

unexplored parts of the deposit. The current

underground workings are developed between

the existing mine area and the Fiscal Quarry as

well as in the north and east of the older

workings. Marble is presently mined up to 190 m

deep.

Room widths are at a maximum of 8 m and

room heights at a maximum of 9 m, with the

pillar planes a minimum of 8 m x 8 m. The

thickness of the rock between two levels is 5 to

6 m, depending on rock characteristics, and the

thickness of the hanging wall rock some 2 to 4

m. At Hermsdorf, the mine uses a modified open

stoping technology with square pillars. The

technology is independent from conventional

mine levels and fits best with the tectonically

disrupted blocks of marble. Underground

preparation, development and mining are

adjusted to the complicated geological

conditions with respect to the performance

characteristics of the mining equipment.

Due to a lack in stability, drives in the wall

rocks are protected by reinforced shotcrete. The

underground production is based on drilling by

electro-hydraulic drilling jumbos and by

conventional blasting. Diesel-powered vehicles

transport the blasted raw material from

underground to the processing plant. A more

than 1 km long decline serves as main mine

entrance and transportation route.

Background to modern miningThe modern era for the mine began in 1989 after

the fall of Communism in the former East

Germany (GDR), when Heitkamp, a large Ruhr

based industrial and construction group, bought

the operation. Heidkamp set about modernising

the operation, which had used small battery

locos and ore cars. The drills and loaders were

also rail-mounted machines, with the loader

passing the material back into the ore car

behind it. Czech-made and Flotman drills were

used. At that time a shaft was used to take

material out; and the five production levels were

connected by shafts as well as steep ramps

equipped with winches.

Following the modernisation programme

beginning in the early 1990s, the mining method

was changed to LHD with underground truck;

initially with two loaders (GHH LF6 and LF7) and

Paus/GHH (MK15) trucks. Whereas formerly, the

battery locos could only handle 4% grades;

underground trucks and LHDs can cope with

grades of up to 22% making it much easier to

access the best material. The increased mine

efficiency is reflected in the workforce figures

and production rates formerly 130 employees

and production of 120 t/d; to the current rate of

320-330 t/d with only 31 employees. This huge

productivity increase is largely the result of the

switch to LHD/truck mining techniques.

Heidkamp then sold the mine in 2008 to

Schn+Hippelein Group, a large natural stone

quarrying group based in Satteldorf.

The current fleet has five loaders and four

trucks. Drill rigs include older Tamrock and

Secoma models, with the third machine a new

diesel-electric Atlas Copco Boomer 281, which is

the most productive in terms of advance rates. It

also has an enclosed air cab, which is much

more comfortable for the operator. It is

designed with service access in mind with easy

access points, allowing for a short turnaround.

The diesel-electric system also allows for fast

relocation from face to face, which can be as

much as 1 km. The 281 can drill 3 m holes in

only 50 seconds, with a 43 mm diameter. Each

face has up to 50 holes; with the hole pattern

determining the blast result, with the most

central hole containing the most charge. The

detonator is connected to the other hole


Older drill rig usedat Geomin until the1980s

The two ball mills usedto grind the marble intofillers for the paint andplastics industries

OPERATION FOCUS

charges via time sets, ie millisecond delays

the more the time sets, the smaller the resulting

blasted rock; up to half second time sets, which

would result in large blocks.

Explosives cartridges from EPC are used and

placed by hand, with only one central electric

detonator. ANFO is then pumped into the holes

using a Multicar explosives delivery truck.

The most advanced machine at the mine is a

new LHD, the Atlas Copco Scooptram ST7, which

is the first to have been delivered to Germany in

June 2011, with a second machine now also

operating at a new fluorspar operation in the

same region. The ST7 service intervals are

longer than the older LHD models; while it

requires fewer spare parts at the same time due

to better wear rates on parts. The ST7 also has

air conditioning in the cab, lower noise levels,

improved lighting and more efficient

emergency/alarm systems. The machine also

has better traction control, which is easier on

the tyres, meaning less tyre changes. But

perhaps the most significant difference in the

current climate is in terms of fuel efficiency the

ST7 achieves 10 l/h with a water-cooled 193 hp,

6.7 l Cummins Tier 3 engine. The older LHDs

typically only achieve 20 l/h and have air cooled

Deutz engines. In power efficiency terms, the

ST7 on-board computer calculates the optimum

power needed at any one time during

operations, allowing for these fuel savings and

lower emissions; as opposed to operating on

full throttle most of the time.

Key safety features include spring-applied,

hydraulically released (SAHR) brakes, automatic

brake testing with diagnostics and logging and

an oil-free cabin environment. Safety is further

enhanced by three emergency machine stop

buttons and a system that applies the brakes,

blocks steering, and prevents bucket movement

when the cabin door is open. The ST7 has a

tramming height of 2,160 mm and a width of

2,280 mm.

IM spoke with one of the ST7 operators, Dirk

Thiele, who commented: The new machine is

very fast, especially on corners. The noise levels

in the cab are much less and the air conditioning

makes it very comfortable. It is also very easy to

load in more difficult faces using the onboard

traction control. The machine is also the only

one to have automatic gears, meaning you can

concentrate only on the main task of loading

instead of driving. No major repairs have been

required on the ST7 since it started operating.

The whole mining area covers 24 ha. As

stated, there is no shaft, with a decline only, and

all of the material trucked out via the ramp and

no crusher located underground. The maximum

haulage distance is some 1.7 km from the

deepest point in the mine. This is currently 596

m above sea level relative to the mine surface at

713 m above sea level. This is an average of 117

m depth, but it varies up to 190 m depending on

the surface topography across the mine

property. Geomin has an Atlas Copco Diamec

212 exploration rig that is used for near mine

and underground core drilling for reserve

extensions.

Production and quality controlMultiple working faces as many as 30 are

used to allow the ability to blend marble

qualities to achieve the desired final result.

Most of the final product is a ground calcium

carbonate (GCC) for the paint industry, where it

forms a filler. The waste material is a dark

phyllite slate.

The mine does not operate at night, but in

two daytime eight hour shifts 6am to 2pm;

and 2pm to 10pm, with two blasts towards the

end of the second shift. Each blast produces

about 200 t of material with about 320-330 t of

marble needed per day to feed the plant. As

stated, the mine operates a conventional room

and pillar method, with 8m by 8m pillars and 6m

by 4.5 m drifts; and a maximum roof height of

about 9 m if the thickness of the marble seam

warrants it. The drifts are not horizontal as

development undulates to following the high

purity marble horizons. Any required scaling is

either done manually or using the older Tamrock

rig. Bolting is conducted using split sets; mainly

using the older Secoma rig.

The blasted marble is driven out via the ramp

to the plant and unloaded onto a grizzly and a

main primary jaw crusher. Following drying and

subsequent sorting by an automated optical

control, the high fineness of the final product is

realized by two one-compartment ball mills.

Windsifter plants and magnetic separators

further contribute to a high-quality product.

The material coming from the different faces

in the mine is constantly monitored for

whiteness and brightness via sample taken to

the on-site lab. The marble is manually

inspected following the jaw crusher to

separate dark and light material. Some faces

are sufficiently good quality for the material

to be used directly but many require

blending.

The processing plant produces calcium

carbonate fillers with diverse grain sizes for a

variety of uses. The filler trademark is Saxolith.

The calcitic fillers of Hermsdorf are

characterized by high fineness and a high

degree of whiteness. The product is sold via

associated marketing company SH Minerals

after the main paint filler market, others include

construction grouts and plastic fillers. The ball

mills can reduce the product size down to as

little as 2 microns, known as the Saxolith 2HE

product.

Additionally, Geomin produces marble and

other local rock gravel for external sources. It is

distributed under the Saxorund brand. IM

OPERATION FOCUS


Underground truckloaded with marble afteremerging from theHermsdorf decline

Room heights canbe as much as 9 m

In their paper at this years SME Annual

Meeting, the University of Utah team

commented that with ever-increasing

demand, low-grade complex ores and strict

environmental regulations, metallurgical

processing options have become limited. Heap

leach technology provides several benefits to

combat these issues including low cost,

flexibility and diversified process conditions.

The paper1 provides an overview of heap

leaching technology with specific emphasis on

chemical aspects. Hence, influencing factors,

advantages and disadvantages, testing

approaches and some fundamentals are

discussed. Finally, heap leach technology for

different ore types (copper, nickel, uranium and

gold) is briefly compared.

They conclude that many factors control the

heap leaching process; however, proper heap

building, mineralogical evaluation of ore,

efficient comminution, and the precise use of

available tests (feasibility approach) must be

undertaken to ensure a successful heap leach

operation. The advancement of heap leach

technology can be easily sensed through the

presence of technology in different ore types.

The growth in modelling studies and

fundamentals will make the heap leach

technology more adaptable to ever increasing

complex ores. Based on the aforementioned

evaluations, more heap leaching operations are

expected to come into the business. However,

many of the areas included in heap leaching

remain open to research with regard to

comminution effects, characterisation tools,

improvements in unit operations (agglomeration

and heap building) and modelling approach.

Outotec is a leading SX/EW technology

supplier with an extensive track record in

building complete plants. Larox, which was

recently acquired by Outotec, is well known for

efficient and reliable filtration process

equipment.

New Outotec Larox DM electrolyte filters,

which are specially designed for efficient

removal of entrained organic and suspended

solids from electrolyte, using the well proven

dual media concept. The Outotec Larox DM filter

package can be delivered as an integral part of

Outotecs SX-EW technology delivery or stand

alone solution to engineering companies and

end users.

This electrolyte filter is suitably designed to

be backwashed using either lean electrolyte or

water.

Outotec says this offers high quality filtration

because adsorption filtration using the well

proven dual media concept reduces entrained

organic and particulate concentrations to a level

of a few parts per million. Production capacities

increase, as does the quality of cathode

products.

The filters use two separate layers of media

for coalescing and for filtration. The upper

media layer provides for organic removal while

the second layer filters particulates in the

electrolyte.

Low electrical energy consumption is a cost-

saving benefit, as the adsorption filtration

technique uses low pumping pressures

compared to alternate solutions utilizing

flotation.

Automatic (PLC) control of the electrolyte

filtration and media cleaning steps at the end of

each filtration cycle ensures maximum filtration

time in subsequent cycles. Outotec says DM

electrolyte filters are delivered as an automated

operational filtration system which can be fully

integrated to any SX-EW solution package.

Using lean electrolyte for backwashing and

returning it to the After Settler after holding in a

backwash collection tank (see flow schematic)

means [these] filters do not reduce the capacity

of SX production. Filter flow rates as high as 275

m3/h can be consistently handled by a single

unit (5.2 m diameter), greatly simplifying the

process.

Typically, multiple units are installed in

parallel for flexibility and expandability to

economically accommodate growing plant

capacity requirements.

With no moving parts, the media cleaning

system ensures maximum media lifetimes.

Typically the anthracite media is replaced every

24 months when combined with Outotecs

proven SX process technology. Garnet lifetime is

considerably longer.

SX/EW


Heaps of new technology

New ideas, chemicals andtechnologies in the heap leachingworld, John Chadwick takes a look

Outotec SX-EW flow schematic withDM electrolyte filters

Paul Keyser, FLSmidth Global Product Director, SX-EW, says FLSmidth is

a relative new comer to SX-EW, but has big plans. For years, through its

legacy companies, the company has supplied both liquid/liquid and

solid/liquid separation technology to support SX-EW operations. Products

such as WEMCO Pacesetters, EIMCO OTG granular media filters, EIMCO

Precoat vacuum filters, Shriver filter presses and Krebs liquid/liquid

hydrocyclones are widely accepted and do an exceptional job for their

respective duties for raffinate, electrolyte, loaded organic and crud and clay

treatment. In addition, FLSmidth is the leader in leaching and supply of

solid/liquid counter current decantation (CCD) circuits for production of

high quality PLS to feed SX-EW. FLSmidth offers complete SX-EW plants,

up to and including overseeing installation and start-up as well as post

commissioning support and service.

In addition to traditional SX-EW technologies using reverse flow mixer

settlers and standard EW facilities, FLSmidth is also investing substantially

in R&D to develop the next generation mixers, settlers and tankhouses.

Early results are promising and point to improved and favourable droplet

formation and significant reductions in settler footprint. As mineable ores

become harder to find and lower in quality and grade, FLSmidth will be

there to offer solutions that make exploiting key resources possible.

Unique to the minerals industry, FLSmidth is the only company that has

the breadth and resources to assist customers with not only the SX-EW

plant, but to reach much farther upstream and take on project

responsibility starting from the mined ore, through both fully mobile and

fixed conveying, crushing, heap stacking, leaching and SX-EW. The

approach reduces the time to first production. The FLSmidth Ore-to-

Cathode, complete solutions approach is what sets FLSmidth apart in the

industry and will be a market driver for growth over the next decade and

longer.

AgitationM C Process has over 20 years experience in tank agitator technology with

over 100 agitators installed globally. The company says it aims for optimal

performance, reduced wear and optimal use of power. Its agitators are

supplied with a bearing housing which ensures the forces generated by the

impeller are not transferred to the gearbox ensuring a more robust design

and longer equipment life.

M C Process has developed a constant velocity impeller, which gives

constant pumping across the width of the impeller; allowing for reduced

impeller rotational speed for the required pumping rate. It says the unique

benefits include lower power consumption, reduced crud formation,

improved mixing efficiency and adjustable head and volumetric throughput.

SX/EW


Krebs DeOiler (FLSmidth) manifolded system for increased capacity

CustomizedIon ExchangeResins forHydrometallurgyHighly selective ion exchange resins to improve recovery of valuable and contaminant metal

Uniform particle size (UPS) perfect for processing of clean solutions

Course particle size resins designed especially for sorption from pulps (RIP)

Effective in the remediation of tails and recycling of mine waters

Proven applications in Gold, Rhenium, Uranium, Copper, Nickel, Mercury, Iron control and other base and rare earth metals.

Just ask Purolite.

Need effectiveremoval/recovery oflow level metals?

Download our Free Ion Exchange App. It containsuseful conversion factors, resources and more.For more information please visit www.purolite.com,email [email protected], or call +1 610 668 9090


SX/EW

The company also claims to be to date the

only supplier of SX plants to use vacuum

infused, fully composite mixer settler tanks

which optimise a huge number of benefits. It

also says its Jet Scrubber is a paradigm shift in

attritioning technology. The principal of the

Burgen Turbine attrition scrubber is that we

need to create more attritioning zones within

the machine, akin to a jet engine or turbine,

where multiple compression vanes in a single

vessel.

Flocculation in SX/EW Mick Bower of Kemira Oil & Mining commented

that the solids/liquids separation processes in

leach/SX/EW plants are very different from most

of minings typical settling applications. In the

case of leach plants the value is actually

contained in the liquid rather than the solid

such as a concentrate. This means that although

the equipment used is essentially similar to that

seen elsewhere on a plant

(settlers/clarifiers/filters) their operation is

different. The settling of solids in low pH

solutions is actually straightforward when using

the correct types of flocculant, such as Kemiras

Superfloc N100. The most important aspect for

reagent selection in these plants is the

downstream compatibility with the SX process.

The SX stage is very sensitive to contaminants,

poor selection and application of reagents can

lead to significant problems with crud formation

and excessive phase disengagement times.

Control over the provenance of the reagents is

often overlooked and plant operators should

look to source from the larger manufactures

such as Kemira who can guarantee the

consistency and compatibility of their products.

What may be acceptable as a flocculant for a

tailings thickening application could easily

upset the SX circuit.

Managing the interaction between

flocculation and SX is the key to running a

successful operation. Having both a qualitative

and well as a quantitative aspect to consider

makes the process a lot more complex than

typical tails thickening. Initially we would look

to control the solids in the overflow with a target

somewhere between 20 and 50 mg/l but we

also need to minimise the residual flocculant

effects. This means simply adding a higher dose

as you may do with other thickeners is not an

option. Minimising the residual floc in the

overflow is influenced heavily by having a good

addition scheme such as properly designed

feedwell lances and effective dilution streams.

Design and the maintenance of the make-down

and dosing equipment used with the flocs are

very important as poorly dissolved material will

track through to the overflow and eventually

into the SX circuit. One common problem has

been that a lot of operators have expanded

plants, increasing the flocculant dosage but

have not added sufficient extra capacity to the

make-down system thereby shortening the

effective residence time.

As the technology becomes more advanced

it will also become less forgiving and the level of

operators understanding of the interactions is

key. The processes are becoming more like the

chemical industry than a mine and a high level

of training is required. Typical reactions such as

increasing reagent dosages in the event of a

plant upset may not have the desired effect.

The trend since the early plants has been to

move away from filters over to lower cost CCD

trains and plants are now starting to be built

with high compression thickeners. Clarifiers are

becoming more common and Kemira is looking

at chemistries for improving this further. The

difficulty being that a lot of the conventionally

used reagents are incompatible with the SX.

Scale control in leach plants is of particular

interest to Kemira. Heap leach operations are

dependent on the effective distribution of the

leachate over the heap and scale formation can

be a serious problem blocking the wobblers or

emitter pipework. Although less common in

agitated leach plants it is often seen in the leach

pachucas and PLS lines. The most common form

is gypsum and although there are a large

number of reagents effective against gypsum

the issue is again compatibility with the SX and

reagent choice needs careful consideration.

SX reagentsCytec notes that largely unchanged over the

last 30 years, the SX process employs a very

small number of highly specific oxime molecules

which are ideally tailored for this application. As

a result of this extraordinary class of

extractants, copper SX is the least complex

process of its kind and also the most versatile.

Despite this there are always many ways in

which to optimise an SX process, particularly

using the experience and toolkit of the reagent

su

eng mining july 2012

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