Selenium 101 Selenium 101 and the Way Forwardand the Way Forward

Harry OhlendorfStrategic Advisory Panel on Selenium Management

H2oh! Awareness and Action WorkshopMay 4, 2011

Presentation outlinePresentation outlineWhat is selenium?Why is it increasing in the Elk

River?Why should we care that it is

increasing?How will Teck reverse the trend

and eliminate the problem?

What is What is seleniumselenium??A semi-metallic (“metalloid”)

element similar to sulfur that is found in some rocks, soil, coal, petroleum, etc.

Complex chemistry, with four main chemical forms; converts from one to another (each with different chemical properties)

Many industrial applications

Selenium Selenium biogeochemistry biogeochemistry at Teck Coal mine sitesat Teck Coal mine sites

Solid phase sources of SePyrite, Gypsum, sorbed

SeO32-

Mineral surface

SeO42-

Abundant organic carbon

Se0

biofilm

Groundwaterflow path

SeO32- Se 2- Pyrite,

Fe(Se,S)2

After Kirk, 2011

Organo-Se

Sorbed SeO3

2-

GypsumCa(SeO4,SO4).2H2O

Microbes Aerobic

Facultative

Anaerobic

What is selenium (cont’d)?What is selenium (cont’d)?An essential trace element for

human and other animal nutrition that has a very narrow range between what is adequate and what is toxic

Bioaccumulates readily, especially through aquatic food webs

Largest step in bioaccumulation is from water to bottom of food web (like algae); typically may be 1000X

Selenium bioaccumulation Selenium bioaccumulation from water from water (Source: Chapman et al. 2010)(Source: Chapman et al. 2010)

What is selenium (cont’d)?What is selenium (cont’d)?From algae or suspended

particulates to insects, typical bioaccumulation factor is 1 to 3X

From insects to fish, typical bioaccumulation factor is ~1 to 1.5X

From food to bird egg, typical bioaccumulation factor is 1.5 to 2X

Selenium is transferred from the adult female fish or bird to her eggs; hence the concern for effects

Why is it increasing in the Why is it increasing in the Elk River?Elk River?Large masses of waste rock are

moved to reach coal deposits in the Elk River watershed

Selenium is released from the waste rock through interactions of oxygen, water, and microbes

As the amount of waste rock increases, more selenium is mobilized to streams and ponds

Correlation between Correlation between concentration of selenium and concentration of selenium and waste rock volumewaste rock volume

0

1

2

3

4

5

0

1

2

3

4

5

1960 1970 1980 1990 2000 2010

Cum

ulati

ve W

aste

(bill

ion

bcm

)

Se (µ

g/L)

Se at Hwy 93

Cumulative waste (bcm)

P:\02_MULTI_SITES\Elk_Valley_Coal_Corp\1CE003.001_Selenium_Geochemistry\Selenium_Release_Model\2009-06_Loading_Empirical\Compiled_Flow_Loading_info\[Se_conc_vs_waste_1CE003.001_CK_REV00.xlsx]

Cumulative mine rock in Cumulative mine rock in Elk ValleyElk Valley

BC Water Quality Guideline

Highway 93

Sparwood

≈ 6% Increase Per YearSelenium concentrations in Selenium concentrations in Elk RiverElk River

Why should Why should we care that it is we care that it is increasing?increasing?Two main concerns are 1)

potential effects on fish or birds (especially reproduction, the most sensitive endpoint) and 2) possible effects on people (from drinking the water at some upstream locations)

Selenium cycles through the food web and gets accumulated, especially in ponds and lakes

Selenium Cycling in Aquatic Selenium Cycling in Aquatic SystemsSystems

Note: Solid arrows indicate pathways by which selenium is remobilized from sediments into the foodchain.

Source: Lemly and Smith (1987)

How will Teck reverse the How will Teck reverse the trend and eliminate the trend and eliminate the problem?problem?Teck commissioned the Strategic

Advisory Panel on Selenium Management in 2010 to provide advice about sustainable mining practices

The Panel produced a report with a series of recommendations based on input from diverse sources and evaluated options based on environmental, social, technical and economic criteria for sustainability

The Panel’s Process for The Panel’s Process for Production of the Strategic Production of the Strategic PlanPlan Establish the Panel Charter

◦ Goal and objectives◦ Conflict of Interest policy◦ Performance measures◦ Schedule

Information Gathering and Analysis◦ Two Panel Sub-Groups: Technical and Stakeholder◦ Tours of Elk Valley and Cardinal River operations

Corporate Risk Assessment Stakeholder Mapping Stakeholder Engagement

◦ Fernie and Hinton Workshops Structured Decision-Making Production of the Report

Stella Swanson, Chair

Rob Abbott

Wes Funk

Lisa Kirk

Gord McKenna

Tom Sandy

Harry Ohlendorf

Mitigation methods for Mitigation methods for sustainability of miningsustainability of mining

Water treatment◦ Treat mine effluent waters

Water management◦ Reuse Se impacted water◦ Divert clean water around rockdrains◦ Divert clean run-on water away from dumps◦ Reduce infiltration with dump covers

Dump design to reduce Se loading◦ Maximize pit backfill◦ Selectively handle and encapsulate Se material◦ Eliminate Se material in rock drain cross valley fills

In situ microbial source control◦ Interbed CCR/tails with waste rock◦ Control oxygen, moisture, lithology (carbon)

to affect reduction Mine planning

◦ Change from surface to underground mining ◦ Design facilities for both resource recovery

and waste management through selective handling, sequencing, and placement

New Dump PracticesNew Dump Practices

Teck actionsTeck actionsAdopted Panel recommendationsCreated two full-time selenium

management positionsWithdrew plans for Line Creek Mine

expansion to reevaluate selenium management actions

Initiated water treatment pilot testing and water diversion projects, plus evaluation of other capital projects

Developing a research and development program to address uncertainties