tucci_sme paper_2016

Resource Recovery – Case Study

Turning Complete Liability Into Economic

Opportunity

Nicholas J. Tucci

2016 SME Conference

Phoenix, AZ

– Direct Precipitation

• Addition of reagent forces metal solubility and precipitation.

– Solvent Extraction (Liquid-liquid extraction)

• Extraction from one aqueous solution into another immiscible organic solvent.

• Three phases: extraction, scrubbing and stripping.

– Ion Exchange

• Exchange of ions between two electrolytes or between an electrolyte solution

and a complex.

• Widely used technology in waste water treatment and hydro-metallurgical

processing.

December 16, 2016Resource Recovery, Tucci Page 2

Resource Recovery: Selective extraction of economically valuable

minerals from mine waste for a specific next use purpose.

Case Study – Berkeley Pit

– Porphyry copper mine in Butte, MT

– Dewatering pumps turned off in 1982

– Pit-lake began forming in 1983

– Main water inputs• Groundwater from surrounding

underground mines

• Surface water diversions

• Precipitation < Evaporation

– Critical lake level = 5,410’• Expected to reach C.L. > 2023

• Remedy – in perpetuity HDS lime treatment

Berkeley Pit, 1982

5410’ - Critical Water Level

2013 Water Level

5410’ -Critical Water Level

2013 Water Level

Berkeley Pit, 2013

Minimum Clearance = 100’

-Source: MBMG (2011)

Berkeley Pit lake

Tailings Pond

Continental Pit

(active)

Continental Fault

Cementation plant & Horseshoe Bend

Cu-plated steel rails in underground mine water

Lexington Tunnel, Butte

Cu2+ + scrap Fe → Fe2+ + Cu

Copper Recovery Process

Process developed in Butte, MT: W. Ledford (1890)

C. Gammons, MT. Tech

Cu2+ + scrap Fe → Fe2+ + Cu

Resource Recovery:

Copper Cementation

Over 40 million lbs Cu dissolved in B-Pit prior to recovery

Process is 75 - 90% efficient

Berkeley

Pit-lake

~ 150 ppm Cu

~ 30 ppm Cu

December 16, 2016Resource Recovery, Tucci Page 7

– Plant operation: 2004-2013

– 1.3 pit-volumes cycled

through plant.

– Direct: 37 million pounds of

Cu recovered from Berkeley

Pit water.

– Indirect: Significant

improvement of water

quality

Copper Recovery Process

Source: Tucci and Gammons (2015)Annual recovery of Cu (in tonnes) from cementation plant

Effect of Cu Recover on Limnology

Over 47 billion gallons cycled in 9 yearsChronology of the Chemocline

Cu cementation

resumes

December 16, 2016Resource Recovery, Tucci Page 9

Water Quality Impacts~272 million pounds of Fe and 330,000 pounds of As removed in 9 Years

~ 4 months solids collection

Secondary Mineral Precipitation

MBMG, 2011

Scavenging of PO43-, AsO4

3- by FeIII oxy-hydroxides

time

epilimnion

hypolimnion

pit sediment

O2 diffusion

gravitational

settling

Cu cementation

Cu recovery

intake

schwertmannite ← Fe3+ ← Fe2+

Cu2+ + Fe → Fe2+ + Cu

8Fe2+

+ 10H2O + SO42-

+ 2O2 = Fe8O8(OH)6SO4(s) + 14H+

1

December 16, 2016Resource Recovery, Tucci Page 12

– 25-30% decrease in total acidity may

result in significant cost savings for

remedy.

Total Acidity

Acidity Vs. TimeOctober, 2002 June, 2012

Summary

– 9 years of cementation resulted in the production of 37 million pounds of

copper recovery.

– Artificial mixing caused by continuous pumping changed lake limnology

from a meromictic to holomictic state, induced oxidation of dissolved Fe2+

and caused subsequent precipitation of secondary ferric compounds.

– Dissolved Cu and Fe concentrations have been cut in half

– Dissolved As and P concentrations decreased by an order of magnitude

– Total acidity decreased 25 – 30 percent, resulting in potentially significant

reductions in treatment costs.

Future Resource Recovery Potential: Estimated Metal Value in Pit

12/16/2016Resource Recovery, Tucci 14

Metal Average Concentration Mass in Pit Lake Commercial Unit USD/commercial unit Value in Pit

(2012) ug/L lb Feb-16

Al 288173 102,000,000 lb 0.69 $70,380,000

Mn 240570 85,100,000 kg 1.48 $57,249,091

Cd 2050 725,000 lb 0.56 $406,000

Ce 890 315,000 kg 13 $1,861,364

Co 1505 533,000 lb 10.4 $5,543,200

Cu 53643 19,000,000 lb 2.07 $39,330,000

La 250 88,500 kg 10.5 $422,386

Li 254 89,900 ton 6000 $269,700

Ni 1198 424,000 lb 3.68 $1,560,320

Nd 436 154,000 kg 60 $4,200,000

Pr 88 31,200 kg 155 $2,198,182

Rb 47 16,600 100g 1118 $84,415,149

U 723 256,000 lb oxide 34 $24,582

Zn 626706 222,000,000 lb 0.77 $170,940,000

Pd 21.7 3,600 troz 775 $87,432,859

Total $526,232,833

Resource recovery analysis is a cost-effective approach that has the potential to

significantly reduce the cost of treatment, and should be considered as a tool in any

life-cycle management plan during mine closure.

Direct cost recovery potential is significant.

Treatment Optimization: resource recovery can improve overall water quality, and

indirectly reduce the costs associated with treatment.

Offers a sustainable approach to mine closure that is often encouraged and

promoted in today’s regulatory environment.

When life hand you lemons……..turning a negative into a positive is often

associated with improved public relations.

December 16, 2016Presentation Title Page 15

A Remedy that Can Pay for Itself – Advantages of Resource Recovery

References

Castendyk, D.N., Balistrieri, L.S., Gammons, C.G., and Tucci, N.J. (2015) Modeling and management of pit lake

water chemistry 2: case studies, Applied Geochemistry 57 (2015) 289-307

Duaime, T.E. and Tucci, N.J. (2011) Butte Mine Flooding Operable Unit Water-Level Monitoring and Water-Quality

Sampling 2010 Consent Decree Update, Butte, Montana1982-2010. Montana Bureau of Mine and GeologyOpen File Report 609.

Tucci, N.J. and Gammons, C.G. (2015) Influence of Copper Recovery on the Water Quality of the Acidic

Berkeley Pit Lake, Montana, USA, Environmental Science and Technology 49 (2015) 4081-4088

Special thanks to Montana Bureau of Mines and Geology In Butte MT

Thank You

Nicholas.Tucci@aecom.com

February 23, 2016

“Pollution is nothing but the resources we are not harvesting. We allow them to be

dispersed because we’ve been ignorant of their value” – R. Buckminster Fuller