Environmental Assessment Marathon Platinum Group

Metals and Copper Mine Project

Lakehead University

FORE 4251 Environmental Assessment

Timothy Sobey, Nichola Ellis, Neil McDonald, & Stephanie Casutt

Content

• Project description

– Geological and social description - Neil

– Environmental assessment - Nichola

• Potential environmental impacts and recommendations

– Acid mine drainage – Nichola

– Erosion and sedimentation – Stephanie

– Contaminants in Lake Superior – Tim

Project Description

Nature of Project

• Stillwater Inc.

• Copper + Platinum Group Metals

– 3 open pits

– Ore processing plant

– Tailings (mine rock storage)

– Access road + transmission line

– Explosives factory

– Water management facilities

– 22,000 tonnes per day, 11.5 years

Geological & Social Description

• Typical of Lake Superior north shore

• 10 km north of Marathon (~4,000 population)

• Economy

• Ojibways of Pic River First Nation

Environmental Assessment • Designated Comprehensive Study

(19/7/2010)

• Fisheries and Oceans Canada and Transport Canada provided advice to CEAA

– Species at risk

– Required approval under NWPA

• Concerns from local groups, First Nation and Métis

• Proposal changed to Joint Panel Review (7/10/2010)

• Confidentiality agreement

Potential Environmental Impacts

Source picriver.com

Acid Mine Drainage • Oxidation of reduced

sulphur compounds

– Acidic conditions pH=2

• Metals dissolved by acidic conditions

• Deposition greatest at point of entry and convergence

• Neutralizing capacity of bedrock and waters

• “Yellow boy”

Effects of AMD on Aquatic Environment

• Minimizes biological oxygen demand

• “Yellow boy” settles and smothers benthic organisms and habitat

• Plankton diversity reduced with pH <4

• Fish populations experience acute and chronic toxicity

• Instances of juvenile fish and larval mortality

Recommendations – AMD • Management of water, tailings,

and waste rock

• Consistent monitoring of storage facilities to reduce oxidation potential

• Addition of limestone into watershed reduces acidity

• Permeable reactive barriers to improve bacterial sulphate reduction and metal sulphide precipitation

– Remove iron and other metals from mine discharge

Sedimentation and Erosion • Crucial naturally occurring process

• Accelerated rates of erosion caused by natural & human events

• Degree of erosion depends on variety of factors

–Soil type, slope degree & length, vegetative cover

• Disturbed large quantities of sediments are transported by water erosion downstream

• Movement of soil affects soil organisms, vegetation and revegetation efforts

Sedimentation & Aquatic Organisms

• Increased risk to survival & well-being of aquatic organisms

• Gold mining may cause significant environmental changes

• Certain concentrations of sediment kill fish directly

• Harmful short-term impacts

• Proponent has identified spawning habitat in streams that will be directly affected by project

– Rainbow trout (Oncorhynchus mykiss)

– Chinook salmon (Oncorhynchus tshawytscha)

• Rainbow trout display three life histories strategies

• Fry feed primarily on invertebrates

• Impact to fish growth from changes of quantity and composition of food resources

Rainbow trout

Recommendations – Erosion and Sedimentation

Prediction

• Measurement and predictions related to site hydrologic variables

– Precipitation, runoff, stream flow

• Spatial and areal characterization of gross erosion and sediment yield

• Analytical software programs and GIS applications provide spatial evaluation and potential sediment yield

Recommendations – Erosion and Sedimentation Mitigation

• Best Management Practices

• Protection of soil surfaces once exposed, control amount of runoff, reduce sediment deposition and transportation

– Immediate and temporary control

• Site specific conditions determine which methods are appropriate and when they should be implemented

• Stillwater Inc. mitigation approach

Potential Contamination of the Lake Superior Basin

Overview •Marathon Platinum Gold Metals (PGM) has

done extensive work preparing a project overview outlining existing biophysical conditions at proposed site

•Currently 10 abandoned mines with tailings, 12 closed/under closure mines, 4 operating mines and 3 mines under development including Marathon copper mine

Mills and Mines on Lake Superior

• Pulp mills: Contributor to historic Lake Superior pollution

•Murphy Oil refinery

•Mining activities can potentially have disastrous human and environmental impacts

•Marathon PGM plans to construct dams which will create waste rock holding areas. Dams will follow traditional waterways en route to Lake Superior

Recommendations for Lake Superior Basin

•Use of dyes or solid water tracers

•Mitigation efforts: Depend on data tracers produce. If there is are obvious contaminants travelling from mine to Lake Superior Basin, proponent would have to include alternate pathways created to stop toxins if they are in high enough quantity

Thank You!

Questions or Comments?