.... Specialising in reducing accelerated erosion

Reclamation of Contaminated Lands Adjacent to Lead-Zinc Smelter

COMINCO DUNCAN SLOPE

PHASE I and II

Link to:

Phase III and IV

Location: Adjacent to Lead-Zinc Smelter in Trail, BC

Client: Teck Cominco Metals Limited

Objective: Reclaim contaminated land adjacent to lead-zinc smelter by means of capping with soil suitable for plant growth. Control accelerated soil erosion and establishment of native vegetation.

 

The Duncan Hillside was subjected to significant sulphur fumigation throughout the late part of the 1800ís and the early to mid-part of the 1900ís. This created extremely acidic soils. In addition, particulate deposition on these slopes has resulted in high metal levels. These conditions have resulted in loss of vegetation cover on the slope, leading to severe soil erosion over decades .

 

Terra Erosion Control Limited, in collaboration with Morrow Environmental Consultants, was retained to develop and implement a site reclamation plan, including erosion control measures and establishment of native vegetation. In July and November 2004 re-grading of existing slope was carried out and approximately 0.3 m of soil capping material was placed over the Duncan Slope project area (depth of soil capping specified by client). The area covered was approximately 11.0 ha. and a total of approximately 25,000 m3 of material was placed.

 

Prior to soil spreading by bulldozers, deformed and unhealthy trees on the site were mulched.  This work was coordinated by Sherry Walsh RPF. After soil placement, bulldozers tracked up and down the slope to create cleat marks (surface roughness) for seed microsites and rain catchments. Straw wattles were also installed across the slope to control surface erosion.

 

The site was broadcast seeded and fertilized using a native grasses and legumes mix in conjunction with endo mycorrhizae fungi inoculation. The seeding mix, developed by Dave Polster R.P.Bio of Polster Environmental Services Ltd, was specifically formulated for the site conditions. The species were selected to provide both bunch forming and sod forming covers, while the legumes (trefoil and alfalfa) will provide nitrogen. A variety of native coniferous and deciduous trees and shrubs were also planted.

 

In 2005, maintenance work was required. Sediment accumulated behind straw wattles on steeper slope gradient sections was removed in order to maintain the effectiveness of these wattles as sediment traps. In 2006 the entire area was manually weeded to reduce invasive plant ingress, consisting mainly of Black Locust (Robinia pseudoacacia). As a stand of native trees becomes established on this site, this invasive species is expected to become less of a problem.

The site was monitored in the summers of 2007 and 2008; grasses and legumes were successfully established. Planted native shrub mortality was assessed as moderate, planted black cottonwood and coniferous tree seedling survival was assessed as good to this date.

 
 

Click on photo to enlarge:

duncan slope

Duncan Hillside Treatment Map

 

Duncan Hillside before Reclamation

Duncan Hillside before Reclamation
summer 2004(photo: Teck Cominco Metals Ltd)
Duncan Hillside before Reclamation, summer 2004
Duncan Hillside before Reclamation, summer 2004
Duncan Hillside before Reclamation, summer 2004
Duncan Hillside before Reclamation, summer 2004
   
Duncan Hillside before Reclamation, summer 2004
Duncan Hillside before Reclamation, summer 2004
Duncan Hillside before Reclamation, summer 2004
Duncan Hillside before Reclamation, summer 2004
   
Duncan Hillside before Reclamation, summer 2004
Duncan Hillside before Reclamation, summer 2004
Soil capping in July and November 2004
Soil capping in July and November 2004
 

Soil capping in July and November 2004

Soil capping in July and November 2004

Soil capping in July and November 2004

Soil capping in July and November 2004
   
Soil capping in July and November 2004
Soil capping in July and November 2004

 

Microsite creation for seeding using bulldozer tracks
Microsite creation for seeding using bulldozer tracks
   
Straw wattles installed to control surface erosion
Straw wattles installed to control surface erosion
Straw wattles installed to control surface erosion
Straw wattles installed to control surface erosion

 

   
Straw wattles filled in with sediment, summer 2005
Straw wattles filled in with sediment, summer 2005
Duncan Hillside, summer 2005
Duncan Hillside, summer 2005
 

Duncan Hillside, summer 2005

Duncan Hillside, summer 2005

Duncan Hillside, fall 2005

Duncan Hillside, fall 2005
   

Duncan Hillside, fall 2005

Duncan Hillside, fall 2005

Duncan Hillside, fall 2005

Duncan Hillside, fall 2005
   

Duncan Hillside, spring 2006

Duncan Hillside, spring 2006

Duncan Hillside, June 2007

Duncan Hillside, June 2007
   

Duncan Hillside, June 2007

Duncan Hillside, June 2007

Duncan Hillside, June 2007

Duncan Hillside, June 2007
   

Duncan Hillside, August 2008

Duncan Hillside, August 2008

Duncan Hillside, August 2008

Duncan Hillside, August 2008
 

Duncan Hillside, September 2008

Duncan Hillside, September 2008
 

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Contaminated Lands Reclamation