Montana fishermen are joining with environmental groups to demand a better evaluation of a mining operation that could affect the Smith River.

On Friday, the Montana Environmental Information Center and Earthworks, supported by fishing outfitters from Lewis and Clark Expeditions, sued the Montana Department of Environmental Quality and Tintina Alaska Exploration Inc., a mining company, over an environmental review of expanded mining operations near Sheep Creek, a tributary of the Smith River.

The lawsuit alleges that the DEQ violated three Montana environmental laws when it approved Tintina's application to expand from surface mining to tunneling a mile underground to explore a copper seam as part of the Black Butte Mine, located 10 miles northeast of White Sulphur Springs.

The environmental groups are asking a Meagher County district judge to require the DEQ to complete a more rigorous analysis of the threats to groundwater supplies and water quality along Sheep Creek than the analysis that was included in the assessment finalized on Jan. 16.

“Our livelihoods are dependent on stream flows and the quality of the water,” said Mike Geary, Lewis and Clark Expeditions spokesman. “You want DEQ to be as rigorous as possible, and I don't believe they're beyond reproach in this case.”

The mile-long exploratory mine shaft — 18 feet high and 18 feet wide — would angle below a 45-acre piece of private property, passing through and below the water table. So the company would have to constantly pump groundwater out of the shaft to keep it from filling.

The extracted water would contain toxic metals that are the byproducts of mining, including arsenic, thallium and strontium. The concentrations of those metals in the water would exceed DEQ standards in certain cases.

The lawsuit questions the method that Tintina is using to keep those contaminants out of nearby surface water and why DEQ is allowing the discharge of contaminants in concentrations that exceed health standards.

The attorneys claim that the environmental assessment was inconsistent.

For example, one section of the report said extracted water would be used to restore groundwater supplies, but another section detailed how extracted water would be kept contained so contaminants wouldn't enter the water supply.

“DEQ did not affirmatively demonstrate that Tintina's exploration activities will not result in a discharge to surface waters,” wrote attorney Jenny Harbine.

The eight outfitters of Lewis and Clark Expeditions take clients on 73 fishing trips a year on the Smith River, a stream that can run high and fast during the spring runoff but then drops to levels where boats have to be dragged through certain sections.

The outfitters don't want the Smith River stream flows to drop lower or have the fishery affected by toxins.

More than 4,000 comments were submitted during the public comment period on the environmental assessment. Most opposed the expansion.

Montana Fish, Wildlife & Parks submitted comments opposing the expansion due to the possible negative effects on the fishery. Sheep Creek accounts for 55 percent of the spawning grounds for the Smith and Missouri rivers.

FWP also holds water rights for both Sheep Creek and the Smith River, which are already not met a portion of the time. Any further reduction in local runoff could threaten fish and wildlife in the area, according to FWP comments.

In addition to conducting an insufficient environmental study, the lawsuit claims DEQ failed to provide information on how much additional bond money Tintina would be required to pay should things go wrong.

In the past, Montanans have had to pay for environmental cleanup projects after mining companies took their profits and abandoned mines without reclamation.

Now, companies have to pay reclamation money to the state up-front as insurance that they will restore mine sites after they're done.

Tintina already submitted money to pay for the surface mine that has operated since 2010, but there was no mention of additional bond money for the tunnel in the DEQ environmental assessment.

“My hope would be that you can have good mining and a good environment, but that needs to be confirmed ahead of time,” Geary said. “At the end of the day, who are they, and if they split, who picks up the bill?”

DEQ spokesman Chris Saeger said attorneys were reviewing the lawsuit.

DEQ is working on a more rigorous environmental impact statement for a gold mine in the mountains south of Butte, which is expected to require procedures to ensure low flows in area streams remain sufficient for aquatic life.

Saeger said in a statement last week that DEQ could devote more time to the Butte EIS, “now that we have completed approval for another permit for a mine.”