Rock Creek & the Environment

Rock Creek and the Environment:

As with most modern mines, one of the top environmental priority for the Rock Creek Mine is protection of water quality. After all, the mine is named after the adjacent stream, which is a tributary to the Clark Fork River, which in turn feeds Lake Pend Oreille. 

Rock Creek will utilize several proven water treatment processes in a complete system to ensure all excess water will be effectively "purified" before release to the environment. The main components of the fully designed water treatment systems are as follows:

  • Primary sedimentation removal and equalization of mine water in a surge pond;
  • A Membrane Bioreactor (MBR) ultra-filtration process for removal of nitrates and suspended solids to 0.04 microns; and
  • A final stage ion exchange polishing process of the treated effluent using a nitrate specific resin to meet the 1 mg/L total inorganic nitrogen limit.

The MBR process incorporates the same process municipal wastewater treatment systems have developed over the years and will be used specifically to treat any residual nitrates in the mine's water left over from blasting operations. Membrane bioreactors have been around for more than 20 years, but have only recently taken hold and become cost-effective through the development of new materials and system suppliers. The final water treatment process is an ion exchange process. Ion exchange systems have a wide variety of uses including softening, deionization, water recycling and heavy metal removal and recovery from wastewater. Slightly more than 100 years ago, two English agricultural chemists, H.S. Thompson and J. Thomas Way, noted that certain soils had a greater ability than others to absorb ammonia from fertilizers. They found that complex silicates in the soil performed an ion exchange function. They were able to prepare materials of this type in the laboratory from solutions of sodium aluminate and sodium silicate. In 1906, Robert Gans used materials of this type for softening water. The early materials used were slow in regenerating and lacked physical stability. These first synthetic ion exchange materials which have much improved operational characteristics.

Water that passes through the water treatment system must meet stringent standards of not only the State of Montana, but also the State of Idaho (because the Clark Fork flows into Idaho) as well as the Federal Government. The mine's discharge water will be treated to not only meet or exceed drinking water standards, but also the higher standards for fish and other aquatic life. In other words, the discharge will not only meet the letter of the law, it will be clean enough for fish to live in and children to drink.

In addition to protecting water quality, Revett will:

Protect the Wilderness Including the Lakes: 

  • The average depth from the surface to the mine will be about 1,000 feet;
  • Revett's third party geotechnical experts, in addition to independent experts working with the permitting agencies, have concluded that the use of buffer zones (areas where no mining occurs) is more than adequate to safeguard against any impact to the wilderness surface including hydraulic connectivity to lakes;
  • Revett will not mine closer than 450 feet to the surface, such as areas near outcrops, or within 1,000 feet around Cliff Lake, and leave un-mined pillars along major fault structures; and
  • Lake inflows and outflows will be monitored throughout the life of the mine to verify that no changes have occurred.

Protect and Enhance Recovery of Wildlife Species in the Cabinet Yaak Ecosystem: 

  • Revett will purchase 2,450 acres of high priority grizzly bear habitat to be set aside from future development and managed by the US Forest Service;
  • Revett will fund three position for Montana Fish, Wildlife and Parks for the life of the project to focus on law enforcement, preventing wildlife conflicts, and monitoring of grizzly bear populations;
  • Revett will provide bear resistant garbage containers to employees and others living in grizzly habitat areas;
  • Revett will provide funding for fencing of garbage transfer stations;
  • Revett will bus employees to and from the mine to reduce road traffic;
  • Revett will prohibit employees from carrying firearms within the permit area; and
  • Starting from day one, Revett will construct sediment controls and enhance road surfacing for protection of Rock Creek bull trout habitat.

Enhance State and Local Economies with Long Life Projects: 

  • Revett will obtain full reclamation bonding, thus protecting the taxpayers in the event of economic hardship;
  • Provide at least 330 high-paying jobs for the area for 20 to 30 years; and
  • Provide approximately $50 million per year in taxes, payroll and goods and services purchases to the State of Montana and surrounding communities.