The Montana Department of Environmental Quality (DEQ) approved Tintina Alaska Exploration’s permit to explore for copper near a tributary of the Smith River north of White Sulphur Springs.

The DEQ wrote that after reviewing the proposal by Tintina Alaska Exploration Company for the Black Butte Copper Project, the state believes the company can mitigate any negative impacts from the exploration work. That mitigation would be through “design, or enforceable controls or stipulations or both” imposed by DEQ or other governmental agencies, the Independent Record reported.

Those requirements include methods for containing soil that may contain metals that contribute to acid mine runoff; having an archaeologist present to protect a prehistoric site that was identified and weekly surface water and ground water monitoring, with the results to be submitted monthly to DEQ.

The exploration permit under the Final Mitigated Environmental Assessment doesn’t permit the actual mine; it only allows Tintina to build a 5,200-ft decline which will let it get a better look at whether it’s economically feasible to mine for copper there.

In the 60-page draft document, Tintina had proposed putting the underground materials it hauls out of the decline into two piles lined with a thick, non-permeable barrier. The “PAG” pile is of Potential Acid Generating materials, and is estimated to include about 30 percent of the rock. The remaining materials go into the “NAG” pile, which is the Non-Acid Generating rock.

Water that falls on the rocks will be collected and treated if necessary. The PAG pond would have the capacity to store 1.9 million gallons of water, while the NAG pond would have a 4.1 million gallon capacity.

If Tintina decides that it’s not feasible to develop the copper mine, the company will put the PAG rocks back into the decline, cover it with a concrete barrier, then put the other rocks on top of that and reclaim the site. DEQ believes that by burying the PAG, it no longer will create acid runoff.