The federal agency approved an extensive expansion of the Gunnison County longwall mine, allowing West Elk to mine up to 19 million tons of coal from leases covering 1700 acres underlying National Forest Service lands that neighbor its current leases.

The growth could expand the mine’s lifespan by three years.

However, Earthjustice – which has filed for the halt on behalf of the High Country Citizens’ Alliance, WildEarth Guardians, Rocky Mountain Wild, and the Sierra Club – said the BLM”s decision is a violation of environmental laws.

“Protecting our forests is good for wildlife, for recreation, for clean water, and our economy,” said Earthjustice attorney Ted Zukoski.

“BLM should ensure Colorado’s forests are conserved, not chainsawed and bulldozed.”

According to the group, West Elk’s plans include 6.5 miles of new roads, the drilling of 48 natural gas drilling pads on roadless forest, and the “waste” of millions of cubic feet of methane daily.

“This mine expansion is a lose,lose,lose proposition,” WildEarth Guardians’ Jeremy Nichols said.

“The public loses their mountain backcountry, loses millions of dollars from wasted methane, and loses because of more coal pollution. This reprehensible waste of irreplaceable public resources only serves the greedy bottom line of Arch Coal.”

The groups also maintain that the roadway and drilling area is a habitat for the lynx.

An Arch spokeswoman did not respond to a request for comment.

If the expansion goes ahead, the coal from the new area will be transported using the existing infrastructure systems and surface facilities, according to the BLM.

West Elk, the second most productive coal mine in the state, received approval to incorporate the property in 2012 and was given two environmental grants for the expansion from the Forest Service, one of which was overturned on grounds that the approval failed to explain landslide risks and weakened protection for lynx and bald eagles.

This is not the first issue the expansion plan has had with environmental groups; though the BLM decided last year that the mine’s expansion would have no significant environmental impacts, an administrative appeal filed by Earthjustice asserted last September that the expansion violated laws meant to protect wildlife, air quality and forest lands.

Conservationists have said that loopholes in Colorado law made the state’s environmental protection for roadless areas particularly vulnerable to industrial development.

For its part, Arch has maintained a consistently positive reputation for environmental responsibility at West Elk, which has operated for more than 12 years without a state environment violation.

As recently as March 2012, the mine received an environmental excellence award from the state reclamation, mining and safety division.

Since 2000, West Elk has won 17 pollution prevention and reclamation awards.

The mine currently produces six million tons of coal annually and employs 350 workers.