DEQ Issues Record of Decision on the Black Butte Copper Project

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Helena, MT April 9, 2020 MT. Department of Environmental Quality

The Montana Department of Environmental Quality has issued its Record of Decision for the permit applications submitted by Tintina Montana, Inc. for the Black Butte Copper Project. Tintina proposes to construct, operate and reclaim a new underground copper mine to be located approximately 15 miles north of White Sulphur Springs in Meagher County, Montana.

Tintina submitted applications to DEQ for an operating permit under the Metal Mine Reclamation Act, a Montana Pollutant Discharge Elimination System permit under the Montana Water Quality Act and a Montana Air Quality Permit under the Montana Clean Air Act.

DEQ analyzed the project under the Montana Environmental Policy Act, and issued a Final Environmental Impact Statement on March 13, 2020. The Final Environmental Impact Statement analyzed the potential impacts from the proposed project and alternatives to the project. DEQ has selected the Agency-Modified Alternative.

Today’s Record of Decision is a public notice identifying DEQ’s decision, the reasons behind the decision and any special conditions associated with the decision and its implementation. The Record of Decision lays out the environmental protections that Tintina will be required to meet.

“DEQ staff thoroughly analyzed this project and applied the best available science,” said DEQ Director Shaun McGrath. “Our job is to ensure a proposed project will meet or exceed the environmental regulations set forth in law. This work has resulted in the most protective hard rock mining permit this agency has ever signed.”

DEQ is requiring several stringent measures to ensure water quality standards are protected for stream flow and aquatics:

  • Early in the review process, DEQ identified a potential flow reduction in Coon Creek due to groundwater being diverted for mining activity. To ensure compliance with the Montana Water Quality Act, Tintina must mitigate this potential impact by augmenting flows in Coon Creek. Tintina applied to the Department of Natural Resources and Conservation to acquire the water right permits and water right changes necessary for this mitigation. While limited, per-mining activities will be allowed, DEQ will not allow Tintina to begin any activities that have the potential to impact flows in Coon Creek until the required water rights are in place.
  • DEQ is requiring, and Tintina has agreed to, protective measures to ensure water quality is not degraded. The mine will not be allowed to discharge any water involved in ore processing, only storm water and ground water that has been treated before discharge. No water will be discharged directly to surface water. Instead, the discharge must be injected into the ground where additional mitigation will take place before it reaches surface water, and Tintina must still meet the more stringent surface water quality standards.
  • Tintina originally applied to have a mixing zone, which is where the discharge is mixed with water for dilution, and DEQ denied that request, requiring unprecedented levels of protection. As a result, the mine will need to treat water using advanced technology, including double reverse osmosis typically used for drinking water, to meet the very stringent water quality standards.
  • The mine will also actively monitor water quality at several locations to ensure standards are being met, and will adjust water temperature in real time so there is no harm to trout and other aquatic life caused by temperature changes.
  • Tintina will not be allowed to discharge any water at all during the months of July through September, when nitrogen in the water may stimulate algae growth.
  • DEQ, in partnership with Montana Fish, Wildlife and Parks, is in its third year of a comprehensive baseline algae study on the Smith River to determine possible causes. If the results of the study suggest additional precautions may be necessary, DEQ can require Tintina’s permit to be updated to address possible impacts.

DEQ’s permit approval also includes unparalleled levels of protection to address concerns about the potential impact of acid-producing minerals exposed as a result of mining. DEQ is requiring double-lined cemented tailings facility, progressive backfilling of mined areas, and sealing the mine portal, post-closure, to prevent groundwater flows across reactive surfaces.

For more information, contact: Rebecca Harbage, MT DEQ 406-461-6183 or by email at: rharbage@mt.gov