Multiple Years of Bio-Solids Performance Data and Method Development

Biosolids provide organic matter and nutrients on overburden dumps, overburden-capped waste rock dumps, and tailings, to enhance the establishment of vegetation on reclaimed sites. This program was initiated at the Highland Valley Copper mine in 1996 to test the effectiveness of biosolids application as a potential reclamation treatment on different waste materials and to assess the possible benefits and deleterious effects of the application of biosolids to waste areas. The program also including monitoring to assess the changes to soil, ground water, and vegetation chemistry, and effects on vegetation cover and biomass production on the treated sites.

Initial monitoring results indicate improved vegetation production on both overburden capped waste rock and tailings. Several years of vegetation monitoring is required to confirm impacts of biosolids application on vegetation sustainability. Monitoring results also indicate that increased vegetation growth may not result on all sites where soil moisture limitations are too restrictive. On those sites, other alternatives, such as overburden capping, may still be required. However, biosolids show a potential for decreasing molybdenum availability for plant uptake and increasing the soil water holding capacity which might result in Highland Valley Copper decreasing the thickness of the applied overburden layer or utilizing overburden materials for capping presently rejected due to coarse texture or molybdenum concentrations.