| Popis: |
Water management is an important component of mine closure and reclamation. Successful water management requires consideration of wide variety of factors including: climate, site accessibility, hydrogeology, geochemistry, and engineering feasibility. This case study focuses on the design, construction, performance, and initial monitoring results for a passive water management system at a remote abandoned mine site. The primary design challenges included: cold climate, steep slopes, remoteness, slope stability, and a low potential for revegetation. An innovative design including an automatic siphon combined with an integrated geomembrane cover and interceptor trench system was designed and constructed to prevent clean water from contacting the tailings and becoming contaminated. Post- remediation monitoring indicates that the passive system is functional and has reduced loading of metals to the shallow groundwater flow system. A total of 58,874 m³ of water is collected and conveyed around the tailings on an annual basis. The contaminant plume downgradient of tailings pond has begun to shrink, and annual contaminant loads have been reduced by an estimated 11,562 kg of sulphate and 505 kg of zinc in addition to other metals. A long-term monitoring and maintenance plan that uses an automated data collection system has been developed to ensure that risk controls remain effective and satisfy the provincial and federal regulations. |
