The Rock Creek Mine has been a hot topic in Sandpoint for decades. A permit application for this proposed underground copper and silver mine in northwestern Montana was first filed in the late 1980s by ASARCO. Ownership of the mining rights changed hands several times, but they are now held by the Hecla Mining Company of Coeur d’Alene.
An environmental impact statement was completed in 2001. The project was subsequently challenged in court by the Rock Creek Alliance. The judge ordered the U.S. Forest Service and mining company to prepare a supplemental environmental impact statement (SEIS), a draft of which is now available for public review and comment.
After spending many hours last week reviewing the draft SEIS and the mine’s potential impacts to North Idaho, here is my take:
- Under the proposal, Hecla would be authorized to build an evaluation adit underneath the Cabinet Mountains Wilderness. This horizontal shaft would be used to collect more information about the ore body and groundwater flows. The Forest Service also proposes to authorize full-scale mine development and production. Because so much of the analysis in the SEIS is based on models with a high level of uncertainty, we feel it is premature to approve full-scale mine development at this time.
- Perhaps the greatest uncertainty relates to what impact the mine would have on the water levels in the high mountain lakes above the mine and stream flows in Rock Creek and the East Fork Bull River. Analysis of this issue in the SEIS relies heavily on models, but models are only as useful as the data entered into them. The evaluation phase of the project would yield greater certainty about the potential impact of the mine on surface water quantity and stream flows.
- If stream flows in Rock Creek and the East Fork Bull River are substantially reduced, then the Rock Creek Mine would also indirectly affect bull trout populations inhabiting those streams. The SEIS suggests that substantial habitat loss is not anticipated, but this stance has not been quantified. Before the full-scale development of the mine is approved, the models should be updated using data collected during the evaluation phase.
- Some of you would probably like to know how a mining company can operate underneath a protected wilderness area. The patented claims at Rock Creek were filed before the wilderness area was established. Perhaps the biggest threat to the wilderness is the potential for a ventilation shaft to be constructed there. The ventilation shaft would only be constructed if necessary to ventilate the underground workings. The Forest Service and Hecla should evaluate whether other ventilation options are available that would avoid disturbing the wilderness area above the mine.
- The formations that would be mined at Rock Creek appear to be low in sulfides, so the potential for acid mine drainage also appears to be low. When exposed during mining operations, sulfides can react to form sulfuric acid and pollute streams and rivers if left untreated. Again, further evaluation of the ore body would either confirm or disprove this analysis in the SEIS. The Forest Service would require Hecla to post a bond to treat any contaminated water flowing from the mine in perpetuity.
- Heavy metals released from the ore during the milling process would settle out, mix with the tailings, and be deposited into the tailing impoundment not far from the Clark Fork River. If the tailings impoundment ever failed, the tailings and heavy metals could end up in the river. Heavy metals recovered during the milling process should be disposed of in a more secure location.
- The potential for the ground above the mine to subside is another concern. The Rock Creek Mine would be developed using the "room and pillar method." Imagine a large room inside a building where pillars are used to support the ceiling. If those pillars are not big enough, the ceiling either collapses or sags. Subsidence occurred at the Troy Mine just across the Bull River Valley. Hecla proposes to leave larger pillars at Rock Creek than it did at Troy, but it’s unclear how large the pillars need to be to prevent subsidence.
- Perhaps the one environmental benefit of the mine is the grizzly bear mitigation plan. Hecla would be required to acquire perpetual conservation easements or to purchase replacement grizzly bear habitat (2,350 acres). Of this, 53 acres would be acquired prior to construction of the evaluation adit, an additional 1,721 acres prior to mine construction, 10 acres prior to the air-intake ventilation adit, and 566 acres prior to mine operation. In addition, habitat improvement would be required on 484 acres, 5.2 miles of roads would be closed, and a biologist would be funded to undertake conservation work.
Not discussed in the SEIS is my longer-term fear about what happens to the mining claims once the mine is closed. Unless the claims are relinquished at the end of the operation, it’s possible that another company could reopen the mine sometime in the future. In other words, who knows what the lifespan of this mine really is?
I will submit comments on behalf of ICL, and I urge you to submit your own comments on Rock Creek Mine. Thanks for speaking up for Idaho’s clean water and wilderness!