RMK Feasibility Study
Meridian Gold Company is closing this former gold mine in the foothills of the Sierras. The mine is located in an area with difficult geology (fault zones, dikes) and poor natural water quality (TDS ranging from 500 to over 15,000 mg/L and naturally-occurring arsenic). Furthermore, it is difficult to differentiate the native water from the mining impacts. Four of the waste management units were constructed and closed under the variance provisions of Title 27, California Code. Saline water discharges developed at several locations as groundwater levels rose after mine pit dewatering ceased.
- Performed feasibility studies to develop and support closure plans that address residual mine wastes and mining impacts to ground and surface water.
- Developed and evaluated alternative approaches to improve containment and mitigate unavoidable impacts.
- Detailed geochemical evaluations, fate and transport analyses, water balance analyses, engineering, and cost estimating were performed as part of the feasibility study.
- Conducted assessments of the performance of the existing mine waste management units (i.e. tailings, impoundments, process water pond, overburden piles, and pit lakes) to develop and support closure plans.
- Provided the basis for obtaining a National Pollution Elimination Discharge System permit to seasonally discharge accumulated saline water during flood flows in the creek.