The Montana Department of Environmental Quality has chosen the best way to finally close a Lewistown area mine, but Montana could once again be stuck with the bill.

On Friday, the DEQ published a final environmental report detailing requirements for the protection of water and soils as part of the proposed closure of the CR Kendall Mine in the North Moccasin Mountains north of Lewistown. The problem is the mining company, ATNA Resources Ltd., declared bankruptcy five months ago.

While most of the 1,040-acre strip mine has been reclaimed, the processing pads must still be dealt with, and contaminated water is still being treated and will need to be for the foreseeable future.

The strip mine, which was fully active until 1995, has waste rock that can contaminate both groundwater and surface water with excess levels of arsenic, antimony, selenium, thallium, cyanide and nitrate. Some of the contaminants were created by the cyanide-leaching process used to extract the gold from the waste rock. Montanans voted to ban cyanide-leach mining in 1998.

Contaminated water has already affected four watersheds, according to the final report. "The groundwater in the monitoring wells and pumpback water has exceeded the DEQ-
7 groundwater quality standard for thallium in most samples since monitoring began," the report said.

Also, elevated levels of salts and other contaminants may be affecting the soil and vegetation on areas that have been landscaped since 1995.

Because of water concerns, DEQ chose an option that would require the mining company, ATNA Resources Ltd., to install a system that would pre-treat contaminated water draining from the process pads before it is mixed with other mine drainage. The mixed water would be pumped back into the ground. Specifically, pre-treatment could remove arsenic and thallium if levels exceeded health standards. Thallium is more toxic to humans than mercury, cadmium, lead, copper or zinc, according to the National Institutes of Health.

This option goes a step further than the company’s original proposal, which was to capture all the water at the end, remove the thallium, and then pump it into the ground. But that wouldn’t have done anything to reduce arsenic levels.

This is supposed to be the final step in a process that started in July 2012 when ATNA Resources submitted an amended plan for final water management and treatment. After hammering out some details with the company, DEQ issued the initial report about a year ago. Now the final report may have come out too late.

On Nov. 18, Atna Resources filed for bankruptcy, claiming to have only $200,000 cash on hand. In a news release, Atna CEO James Hesketh cited several reasons for the company’s troubles, including “low gold prices in 2015, the continued indifference in the market for gold company equities, a lack of capital in the mining sector, a lack of development capital and operating issues resulting in a significant shortfall in third-quarter gold production at the Pinson mine, and a depressed market for the sale of idled mining equipment.”

During the past months, some work has continued at the site, but will the company be able to pay to complete the CR Kendall Mine closure to DEQ’s requirements?

Jen Lane in the DEQ Compliance Division said only the company could answer that. While finalizing the report, DEQ has not communicated with Atna Resources. Once the final record of decision is published in 12 days, the agency will probably learn more.

Jim Volberding, Atna manager for Montana Operations, could not be reached for comment on Monday; an employee said Volberding had called in sick.

Atna Resources also owns 900,000 acres of mineral rights in western Montana including six unpatented claims of the Blue Bird Prospect near Philipsburg.