The decision will allow West Elk to mine up to 19 million tons of coal from leases covering 1700 acres underlying National Forest Service lands.

The coal will be transported using the existing infrastructure systems and surface facilities.

The second most productive coal mine in the state received approval to incorporate the property earlier this year 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.

Though the Bureau of Land Management (BLM) decided 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.

The BLM approval said that the Colorado roadless area rules specifically provided for coal mining in the tenement near West Elk by allowing for the construction of temporary roads.

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 tonnes of coal per annum.