Water Quality

Protecting water quality and aquatic habitat is fundamental to the Rock Creek mine plan. After years of study, a number of measures have been put in place to reduce the mine’s potential impacts:

  • road improvements and sediment controls are projected to reduce sediment load by 400 tons per year from current conditions, which will actually improve aquatic habitat
  • water collected throughout the mine life will go through a multi-stage water treatment process to ensure that it meets standards for protection of fish and other aquatic life
  • the majority of water will be recycled and reused throughout the mining and milling process; it will also remain in a closed loop, maximizing usage
  • extensive monitoring and testing will be done throughout the mine life to verify that strict water quality standards are being met


Water Quality Mitigation Measures
  • Technical Advisory Groups (TAGs) to be formed by agencies for groundwater, paste tailings, and possibly geochemistry to manage implementation of mitigation and monitoring
  • collection of runoff and seepage in affected areas stored in lined ponds, directed to multi-stage water treatment plant
  • Phase I treated water to infiltration ponds; Phase II treated water to diffuser pipe in Clark Fork River
  • discharges require prior approval from Kootenai National Forest and Montana Department of Environmental Quality (DEQ)
  • reduce sediment in Rock Creek by 400 tons/year by using Best Management Practices (BMPs)
  • BMPs to be implemented at 20 locations on Forest Service roads #150 and #2741 for sediment mitigation
    • water diversion structures (rolling dips, open tops, or rubber flaps)
    • slash filter winrows or settling basins installed at outfalls
    • two new culverts on Chicago Peak Road (Forest Service #2741) at stream crossings
    • applying 4”–6” gravel surface
    • ditch relief culverts
    • erosion-control fabric and rock-lined ditches
    • hydromulching disturbed ground to ensure quick revegetation
  • Stormwater Pollution Prevention Plan (submitted to DEQ; 26 outfalls requested)
  • roads to be upgraded and paved in some areas
  • waste rock geochemically tested; only suitable rock used for construction
  • use explosive techniques to minimize residual nitrate/ammonia in waste rock
  • use lined collection ditch around Phase I talus and waste rock slope
  • remove snow accumulation and divert stormwater runoff
  • tailings, process water, and ore concentrate pipelines to be double-walled with leak detection and buried except at bridge crossings
  • monitor wells to also serve as pump-back wells
  • if necessary, groundwater below tailing facility to be captured and treated
  • monitoring alert levels and corrective action plan will be developed to ensure early detection of potential environmental degradation
WP-Icon Rock Creek Water Quality (Fact Sheet)