1

Organic Residuals for Mine Reclamation:

an Overview of Progress in Ontario

Bryan Tisch

Compost Council of Canada, Webinar

November 5, 2014

2

Outline

Overview of mining issues (Mining 101)

Success with papermill biosolids

Green Mines Green Energy Initiative

Moving forward – biochar/carbon in

tailings

3

What are Tailings?

Material rejected from a mill

after most of the recoverable

valuable minerals have been

extracted.

4

Sulphide Oxidation

Acid generating process:

2MS + 3O2 + 2H2O ↔ 2H2SO4 + 2M (aq)

5

Offsite Effects - Dust and Drainage

6

Growth Constraints in Mine

Waste Particle size and structure

Compaction

Lack of organic matter Lack of nutrients

Lack of soil microbes

pH

Metals

7

Background

Work with papermill biosolids initiated at several sites in Ontario (Rio Algom, Vale, Goldcorp)

Vale (formerly INCO), Glencore (formerly Falconbridge) and city of Toronto - possibility of using composted garbage as a reclamation material for mines.

Proposed biodiesel plant in Sudbury

8

Pronto Mine – Elliot Lake

•First tailings reclamation in Ontario with papermill biosolids. •Excellent vegetation establishment. •Mining company estimated savings of $2 million •Paper company biosolids disposal cost halved.

9

Vale – Copper Cliff

1999

2004

2008

10

Vale – Copper Cliff 2004 Assessment

No negative effects from

biosolids cover after ~ 5 years.

11

Goldcorp – Coniaurum Mine

12

Policy Linkages

Organic waste suppliers – no

commitment until mines agree to take material

Mines - no commitment

until regulators willing to approve

Regulators – no approval until

impacts investigated

NRCan

13

Green Mines Green Energy (GMGE)

3-year field demonstration study led by NRCan

to examine technical feasibility of using residuals

Goal - To advance mine reclamation through the

beneficial use of organic residuals for the

sustainable establishment of bioenergy crops

Potential to contribute feedstock for a planned 20

million litre/year biodiesel plant in Sudbury

14

Scope of the Initiative

Four main target areas proposed:

Impact of Organic Residuals on Tailings

Quantity and Quality of Biomass

Economic Feasibility

Communication, Public Education and

Technology Transfer

15

Primary Participants

Mining: Glencore, Vale, Goldcorp, Barrick Gold, Highland Valley Copper, Enterprise Cape Breton

Forestry: Domtar, St. Marys Paper, Abitibi

Consolidated Government: Natural Resources Canada,

Agriculture Canada, Ont. Ministry of Food & Rural Affairs, Ont. Ministry of Environment

Academia/Other: Laurentian University/MIRARCO,

GroBark, City of Greater Sudbury, Metro Vancouver, Green Municipal Fund, NSERC, ORF

16

Demonstration Locations

Vale (Copper Cliff) – acidic Cu/Ni

tailings

Glencore (Onaping) – desulphurized

slimes layer overlying acidic Cu/Ni

tailings

Goldcorp (Timmins) – alkaline gold

tailings (As bearing)

Cape Breton (ECBC)

British Columbia (Highand Valley

Copper)

17

Potential Benefits of Residuals

Tailings dust suppression

Growth substrate

Decreased metal mobility

Progressive reclamation

Reduced liability for mine waste

One waste to reclaim another

Carbon credits

Biodiversity

Alternative land use (long term)

Diversion of organics from landfill

18

Vale Biosolids Delivery

(Winter 2008)

19

Vale – St. Marys Tilling (May

2008)

20

Vale - St. Marys (May 2008) ~3,500 m3 delivered and spread (0.5 ha)

21

St. Mary’s Plot July 10, 2008

22

Glencore (June 2009)

23

Vale

24

Corn/Canola

25

Biomass – corn/canola

0

2

4

6

8

10

12

14

Vale -

Canola

Xstrata -

Canola

Goldcorp -

Canola

Vale - Corn Xstrata -

Corn

Bio

ma

ss

(T

/ha

dw

)

2008

2009

2010

2011

3.3*

0.7*

2.7*

*Seed Yield Ontario Agr. Avg. (2009) was 2.2 T/ha

26

Switchgrass

0

2

4

6

8

10

12

14

2009 2010 2011

Bio

ma

ss

(T

/ha

DW

)

Cave-In-Rock

Sunburst

27

Sunflower (2011)

Biomass (2011) Vale =7.8 +/- 1.7 T/ha (DW)

Xstrata = 7.2 +/- 1.7 T/ha (DW)

28

Willows

29

Willows

30

Rough Economics/Energy

Based on GMGE field results….

Sale of biomass also feasible (consideration for companies not

interested in actually producing biofuel)

Potential profit of $905/ha/yr for canola at Vale. If applied to 60% of

their tailings (1,300 ha)…approx. $1.2 million/yr….just on sale of

feedstock. Could generate up to $4.7 million litres/yr of biodiesel.

Site Crop Yield (kg ha-1)

Profit ($ ha-1)

Vale St. Marys Canola 3,273 (seed) 905

Corn 3,378 (seed) -350

Goldcorp Canola 2,748 (seed) 612

Glencore Canola 706 (seed) -363

Corn 2,469 (seed) -515

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Groundwater Nickel (Vale)

0

100

200

300

400

500

600

700

Aug. 8

/08

Sept.

10/0

8

Sept.

25/0

8

Oct. 3

0/08

Nov

. 4, 2

008

May

20/

09

July 7

/09

Aug. 1

2/09

June

24/

10

July 1

3/10

Aug. 1

8/10

Sept.

29/1

0

Nov

. 30/

10

June

29/

11

July 2

5/11

Aug. 2

3/11

Sept.

29/1

1

Date

Ni (m

g/L

)

St Marys 1.42 m

St Marys 2.2 m

St Marys 3.05 m

2 per. Mov. Avg. (StMarys 1.42 m)2 per. Mov. Avg. (StMarys 2.2 m)2 per. Mov. Avg. (StMarys 3.05 m)

32

Column Study – 5 year duration

33

Goldcorp (Delnite) – As & Fe

0

2

4

6

8

10

12

14

Jan-07

Mar

-07

May

-07

Jul-0

7

Sep

-07

Nov

-07

Jan-08

Mar

-08

May

-08

Jul-0

8

Sep

-08

Nov

-08

Jan-09

Mar

-09

May

-09

Jul-0

9

Sep

-09

Nov

-09

Jan-10

Mar

-10

May

-10

Jul-1

0

Sep

-10

Nov

-10

Jan-11

Ars

en

ic (

pp

m)

Goldcorp Control

20 cm Abitibi

Goldcorp/Abitibi Mix

1 Metre Abitibi

Abitibi Control

0

2

4

6

8

10

12

Jan-07

Mar-07

May

-07

Jul-0

7

Sep

-07

Nov

-07

Jan-08

Mar-08

May

-08

Jul-0

8

Sep

-08

Nov

-08

Jan-09

Mar-09

May

-09

Jul-0

9

Sep

-09

Nov

-09

Jan-10

Mar-10

May

-10

Jul-1

0

Sep

-10

Nov

-10

Jan-11

Fe (

pp

m)

Goldcorp Control

20 cm Abitibi

Goldcorp/Abitibi Mix

1 Metre Abitibi

Abitibi Control

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Delnite Mineralogy - Pyrite

Uncovered tailings Covered tailings (surface)

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Metal Accumulation (3 – 5 years)

No trend of increasing

metal levels in the

biosolids cover (from

underlying tailings)

observed.

No trend of metal

accumulation in crops

observed.

36

Glencore - 2011

37

Glencore – Spring 2014

38

Glencore Fall 2014

39

Glencore Fall 2014

40

Glencore – 2014…..

GroBark compost

N-Viro Soil biosolids

+

41

Other Examples

Glencore Kidd Creek (Timmins)

– black muck cover amended

with mun. biosolids (Toronto)

Kamkotia (Timmins) –

considering mun. biosolids

(Toronto) to help reclaim areas

where tailings removed

More to come…

42

Past and Current Research

Goals • Beneficial reuse of wastes • Diverting organics from landfill • Advancing mine reclamation (productive land use)

GMGE 2006-2012

Consultation • City of Toronto • Vale • Glencore • BHP Billiton • Barrick

Thick (1m) Covers Corn Canola Switchgrass Sunflower Willow

Feasibility Study • Currently not economically feasible

Thin covers Canola Switchgrass Willow Sunflower Big Bluestem

BIOCHAR

Glencore 5 ha covered • 10 ha in 2 years • 96 ha total

Compost + Mun. biosolids (GroBark/N-Viro)

Vale ~3 ha Municipal biosolids

(Toronto)

Impact of C-rich amendments on mine

stability 2013-2016

Characterization Feedstock Temperature Residence time

Impact of Covers Geochemical Microbes

Potential Uses • Soil amendment • Metal sorption • Reprocess tailings • Alternative binders

Signature project

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Science Policy Objectives:

Advance mine reclamation by reuse of organic wastes

Establish long term agri-energy land use on tailings

Improve reclamation options for tailings (i.e. contribute to

social license)

Provide scientific data that documents characteristics of

novel by-products (e.g. biochar)

How can it be used in the mining industry?

Can it be altered to improve metal adsorption?

Improve marketability of products for mining

Potential carbon storage in tailings

44

Biofuel Production

Pyrolysis

Dry

Biomass

Gas

Bio-oil

Char

(20 – 35%)

250ºC

350ºC

600ºC

• Depolyme-

rization

• Am. C

• Polyaromatic

sheets of

graphene

grow

100 µm

45

Impact of C-rich amendments on the long-term stability of mine wastes (2013-2016)

Biochar

Characterization Potential uses

Soil amendment

Metal sorbent

Reprocess tails

Impact of Covers

Post-evaluation GMGE

46

Team: 8 CMIN scientists + …

Collaborators

Ag Canada

Purdue U

Ph. D. student

McGill U

Ph. D. student

Others:

NRC, EC, CanmetENERGY

Industry Stakeholders

Abri-Tech Inc.

Airex Inc.

Pyrovac

Basques

Vale Inc.

47

Soil amendment

As a source for stable C and

nutrient carrier

Next phase for CMIN: scaling up to

experiments in growth chamber

Purdue received $260K grant for

investigating the reclamation of coal

spoils in Indiana (USA)

Metal sorbents

Testing ways to make biochar more

effective metal sorbents (e.g. H2O2

treatment)

Willow and poultry manure derived

biochars were effective sink for Pb

precipitation as pyromorphite =>

potential application currently being

tested for polluted rice lands in

Indonesia

Lab

m-scale

Field

Biochar – Potential uses (on-going)

0

50

100

150

200

250

300

350

0 100 200 300

Cu

se

qu

es

tere

d (

mm

ol

kg

-1)

Cu conc. in solution (mg L-1)

pH 4.5

H2O2-treated

Original

48

Biochar – Characterization 9. Indices for biochar carbon stability

† BW = Basswood; SG = Switchgrass; PM = Poultry manure

Airex 1

BW† 450

BW† 400

Willow 500Willow 450

Airex 2

SG† 500

Basques fineBasques coarse

PM† 500

PM† 450Pyrovac

SG† 450

0.20

0.30

0.40

0.50

0.60

0.70

0.80

0.90

1.00

0.40 0.45 0.50 0.55 0.60 0.65 0.70

Mo

lar

H:O

C

R50

increase in thermal stability

incre

ase

in C

aro

ma

ticity

more stable in soils?

Using a range of biochars derived from various feedstocks and pyrolysis conditions, we

characterized their physico-chemical properties to select the most promising amendments

for reclamation of acidic tailings.

…”a much needed study for all of us manufacturers”…

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Impact of cover: Post-evaluation GMGE

Results indicate improvement

of “soil health” in the

oxidized, acidic tailings:

increased pH, reduced

metal mobility,

increased microbial

activity and diversity of

populations

The study provides proof-of-

concept to support new

research in BMP for mine

reclamation at national scale

(Genomic proposal; B. Tisch)

Cum

ul µ

g C

O2-C

/g tails

(±

SE)

Microbial activity and diversity in oxidized tailings

(0-5 cm) biosolids

0

20

40

60

80

0 20 40 60 80

Incubation time (day)

Under cover; pH = 4.1

Control; pH = 2.6

Activity

(12 ºC; 30 wt.% Hº)

Diversity

(DGGE: 16s rRNA; ~178 bp)

Ctrl Under cover

0 – 5 cm

Biosolids,

cropped

Control

6 year old field plots, Vale tailings, Sudbury:

Sampled June 2013

(149 m x 21 m)

Paper mill

biosolids

Oxidized tailings

50

General Conclusions

The GMGE initiative has demonstrated the technical feasibility of establishing biofuel crops on tailings while diverting organic residuals form landfill.

Tailings can be converted from strictly a liability

to a profit generating operation that involves local communities.

Availability of sufficient volumes of organic

residuals and cost of establishing the growth medium (cover) remain obstacles to larger scale usage

51

Potential Uses • Soil amendment • Metal sorption • Reprocess tailings • Alternative binders

Next Steps

Goals • Beneficial reuse of wastes • Diverting organics from landfill • Advancing mine reclamation (productive land use)

GMGE

Consultation • City of Toronto • Vale • Glencore • BHP Billiton • Barrick

Thick (1m) Covers Corn Canola Switchgrass Sunflower Willow

Feasibility Study • Currently not economically feasible

Thin covers Canola Switchgrass Willow Sunflower Big Bluestem

BIOCHAR

Characterization Feedstock Temperature Residence time

Impact of Covers Geochemical Microbes

Glencore 5 ha covered • 10 ha in 2 years • 96 ha total Compost + Mun. biosolids

(GroBark/N-Viro)

Vale ~3 ha Municipal biosolids

(Toronto)

Carbon in Tailings • CFS • IETS • Universities • NRC • Mining Industry • Biochar producers

Quantify/Augment C storage in tailings

Soil development

52

Considerations for Moving Forward

Odor control when applying

Collection/consolidation of organic residuals

Manufactured soils

Pharmaceuticals/organic content of

residuals

Interaction with tailings

Sound science and demonstrations

Work with regulators in these projects

53

Thank You!

btisch@nrcan.gc.ca