britannia bc - abandoned minesbritannia bc: past, present & future al colodey environment canada...

Britannia BC:Past, Present & Future

Al ColodeyEnvironment CanadaPacific and Yukon Region

al.colodey@ec.gc.ca

Location

x Britannia

Pre-mining conditions

• Exposed ore-bodies (sulphides)occur at summit

• Lower BritanniaCreek fish habitat

• No adverseeffect on HoweSound

Post-mining conditions

• Mining exposedsulphide minerals tooxidation (‘acid rockdrainage’)

• Acidic, metals-richflows from two aditsdrain mine workings

• 2200 adit drains toBritannia Creek

• Larger, 4100 portalflow discharges toHowe Sound

Mining:1902-1974

Plan view of Britannia features and contamination

Sources of PollutionUPLAND SOURCES� Mine drainage

� Contaminated lands

� Oxidized ore in mill area

� Contaminated ground water

AQUATIC SOURCES� Howe Sound sediments

contaminated by tailings andprecipitates

Mine Drainage Sources

4100 Level4100 Level pH 3.7 Flows: 37 to 900+ L/sec Av Cu: 15 mg/L Av Zn: 22 mg/L

2200 Level2200 Level pH 3.2 Flows: 1 to 70+ L/sec Av Cu: 21 mg/L Av Zn: 17 mg/Liron sludge from 4100iron sludge from 4100

Onshore Contamination• Spilled reagents

concentrate, oilsand fuels

• Foreshore areahas oxidizedtailings

• Stabilize/removemill building

Aquatic Effects of Mine Drainage

Loss of Britannia Creek habitat

Lack of Algae & Invertebrates

Toxic conditions to Juvenile Salmon & Bivalves (DFO Research)

Howe Sound Sediments

• 40 M tonnes of high-sulphide tailings to fjord200 m deep

• Chemical stability oftailings not studied

• Covering by plume ofSquamish River glacialsediments (2 cm/y)

Treatment of mine drainage• Lime in the high-density sludgeprocess causesheavy metals toprecipitate

• Plant over-flow isnon-toxic to aquaticlife

• Sludge to on-sitelandfill but Cu, Znrecovery may bepossible

Treatment Plant Costs

1998 conceptual plant costs by AMEC/ H.A. Simons

Total plant costs including pipeline and $4.2 M

contingency, excluding engineering:

Annual operating cost including $0.80 M/yr

on-site sludge disposal:

Federal & Provincial Expenditures

1990-2001

$ K

Mine inspections 30Treatment tests, design, monitoring 402Marine effects research 421Repair discharge pipeline 144

Total 997

Funding by Former Owners

• BC Contaminated Sites Regulations apply strict,joint/several, and retrospective liability forcontamination to former owners

• Apr 2001, BC indemnified all former owners ofBritannia for $30 M cash

• Ultimate remediation costs unknown

Remediation: Key parties• BC Environment (regulator & responsibleparty)

• BC Mines regulates all work at mines

• Owners of surface and mineral rights

• Environment Canada, Fisheries & Oceansadvise on effects & remediation

• Infrastructure Grant application submitted

Other parties with direct interests

• 200 + Britannia Residents• Regional District: planning

and services• Squamish First Nation• BC Mining Museum• Adjacent land owners• BC Mining Industry

Next Steps� Formation of an ‘Operational Entity’� Undertake Workplan Items

� Treatment Plant Design & Infrastructure� Site Remediation: DSI� Treatment Laboratory� Public Displays

Marine Sediment Assessment

Coresparticle sizemetal scanorg Cavs

Grabsas per coresbioassaysinfaunal communty

Sediment Imaging Mappingtowed vehiclesubstrate classificationbiota mapping

Intertidal Sampling/Mapping

- special thanks to Rob McCandless & Mike Hagen