For a relatively small project, a mining company's proposal to dig a few test wells generated a significant number of public comments.

By the end of the public comment period on Monday, the Montana Department of Environmental Quality received almost 940 comments on Tintina Resources' proposal to dig deep test wells in advance of a possible underground mining operation north of White Sulphur Springs.

On June 30, the DEQ released an environmental assessment of Tintina Resources' plan to drill four new deep wells to test the groundwater recharge rates in the area of the proposed Black Butte copper mine.

Three of the new wells would pump water for 30 days from depths of between 200 and 400 feet to learn how quickly the water table drops. The fourth well would monitor groundwater levels.

The concerning issue for DEQ is that at least one of the wells is expected to pass through an area of rock that contains higher amounts of arsenic.

Measurements at a nearby monitoring well show arsenic levels in the water exceed the allowable drinking-water standards set by the Environmental Protection Agency.

In a process known as “land application disposal,” the mining company would use an irrigation system to sprinkle more than 1 million gallons of arsenic-contaminated water slowly over 40 acres while vegetation is still growing. For six hours each day, the water would supposedly be sprayed lightly enough it would evaporate before reaching surface or groundwater.

Tintina Resources spokeswoman Nancy Schlepp said the public might have a misconception about the arsenic levels. While levels exceed human drinking-water standards, they are below limits for irrigation and wildlife, Schlepp said.

By spreading the water over the land, the plan claims the arsenic load in the soil will remain below EPA limits.

But some commenters disagree.

Bruce Farling of Montana Trout Unlimited said he hired a consulting mining engineer to analyze the plan and the engineer doubts that the sprinkling plan would work.

“There is a high likelihood that it won't work, which means the company would potentially violate Montana's nondegradation water quality standard. We don't believe DEQ has the authority to allow that to happen based upon a subjective conclusion about risk,” Farling said in an email.

Montana TU suggested that Tintina Resources should collect more baseline information before the well tests and then collect and treat all pumped groundwater before pumping it back into the aquifer.

In her comments, Earthworks spokeswoman Bonnie Gestring agreed that the arsenic-laden water should be treated because the use of land application at other mines has always resulted in some harmful discharge.

“Even the (land application) system at the Stillwater mine, where there is extensive experience at land application, has resulted in the breakthrough of nitrogen into groundwater,” Gestring said. “As a result, LAD should always be the last resort – particularly in such an important watershed. LAD is not the best method for disposing of pump test water. It is simply the cheapest.”

She also pointed out that the land application calculations used in the plan are based upon the biological abilities of crops, not native vegetation.

A Montana Environmental Information Center petition that gathered almost 370 signatures also asked DEQ to require Tintina Resources to treat the water rather than using land application.

“There's viable, affordable technology out there that they can use,” said MEIC spokesman Derf Johnson. “The vast majority of the people who signed our petition were from Montana, but agencies usually count petitions as just one comment.”

Tintina vice president for exploration Jerry Zieg said he worked closely with DEQ managers to come up with the plan before it was released so he wasn't expecting DEQ to choose the no-action alternative.

“It would be remarkable if they turned it down,” Zieg said.

If DEQ rejected the plan based upon public comment, Zieg said he would talk with DEQ to try to understand what their concerns were.

The company wants to complete the well tests before winter sets in, so DEQ spokesman Chris Saeger said DEQ managers will make the final decision on the proposal within two to three weeks.

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