Mount Emmons Molybdenum Mine Environmental Review and Impacts

Historical context

The modern Mount Emmons saga began when AMAX Inc., a diversified natural resources company with interests spanning molybdenum, tungsten, nickel, and other metals, initiated exploration drilling on the mountain in the 1970s AMAX Inc. — Mount Emmons. Because the deposit lies largely beneath National Forest System lands, the U.S. Forest Service became the lead agency under NEPA, joined by the Bureau of Land Management, the Environmental Protection Agency, the Bureau of Reclamation, and the U.S. Army Corps of Engineers, the last of which administers dredge and fill permits Scope of EIS on Mount Emmons Mining Project. Scoping documents released in 1979 framed the alternatives analysis, including mill and tailings site locations, ore haulage systems, transmission line corridors, and reclamation obligations Scope of Environmental Impact Statement.

A parallel Colorado Review Process coordinated state agency input on water quality, wildlife, and visual resources, the last especially important because the Maroon Bells–Snowmass and West Elk Wilderness areas nearby qualify as Class I airsheds under the Clean Air Act, receiving the highest level of protection for visibility Mount Emmons EIS Chapter. Engineering and environmental baseline studies were commissioned through AMAX Environmental Services, including detailed soil inventories along Mount Emmons and proposed transportation corridors Soil Inventory Mount Emmons & Corridor, surficial geology and soil mapping for the Cabin Creek area Cabin Creek Area and Antelope Creek area Antelope Creek Area, and integrated characterization of the broader Mt. Emmons Project Area Mt. Emmons Project Area. A schematic plan placed mine facilities in the Alkali Creek drainage with ore moving by rail or conveyor through a tunnel beneath Mount Axtell Mount Emmons Schematic Alkali Creek Plan.

Management actions and stakeholder roles

Management of the Mount Emmons review has required coordination among federal, state, industry, and community actors. The Forest Service and BLM lead surface management decisions; the Corps of Engineers regulates wetland impacts; the EPA reviews water quality consequences; and the Rural Electrification Administration and Colorado Interstate Gas have figured into infrastructure planning for electrical power requirements, compressor stations, and gas pipelines that any operating mine would require RE: Navajo Transmission Project Scoping Comments. AMAX, and later Cyprus Amax Minerals Company, advanced the technical case for the project, including a pre-feasibility report describing ore reserves, molybdenite mineralization, and proposed panel caving — a bulk underground mining method in which ore is undercut and allowed to collapse for extraction Mt. Emmons Project Pre-Feasibility Report.

Management approaches center on alternative formulation under NEPA: comparing the no-action alternative, alternative corridors for transmission and haulage, alternative mill and tailings sites, and varying reclamation strategies against baseline conditions in soils, vegetation, hydrology, and visual resources. Subsidence modeling, prepared by COMARC Design Systems for AMAX, projected ground surface effects expected thirty or more years after mining begins as ore is removed by panel caving After Subsidence Mount Emmons Drawings, with companion analyses describing downstream effects on slopes and drainages Effects. Land exchanges have been proposed to consolidate mill site lands, and rights-of-way decisions govern utility and road placement across mixed federal and private ownership Scope of EIS on Mount Emmons Mining Project.

Current challenges and future directions

The most pressing contemporary issue is long-term water quality protection. Acid mine drainage from historic workings on Mount Emmons already requires perpetual treatment, and any expansion would intensify obligations for bedload transport management, sediment control, and metals removal in Coal Creek. Annual reports from successor operators have continued to list Mount Emmons among active molybdenum holdings even as uranium, gold, and coalbed methane have drawn corporate attention elsewhere (US Energy Corp. Annual Report 2006). Comparable coalbed methane reviews in the Raton Basin illustrate how cumulative impact analysis, well drilling density, and demand management programs have evolved in Colorado's environmental review practice Environmental Assessment Record — Raton Basin Coal Bed Methane Alternatives: Activities Common to all Alternatives.

Looking forward, climate change is reshaping baseline conditions: snowpack timing, mesic resource extent, and grouse and big game habitat are all shifting, complicating the use of decades-old baseline studies. Recovery trajectories for disturbed tundra are slow, site index values for forest regeneration remain modest at high elevation, and search and rescue and public services demands on Gunnison County grow with each new development pressure. Future decisions will likely hinge on whether modern reclamation technology and financial assurance can credibly protect transmission networks of streams and wetlands across multi-generational timescales.

Connections to research

Scientific research at the Rocky Mountain Biological Laboratory, located just over the ridge from Mount Emmons in Gothic, provides much of the ecological baseline that environmental review depends upon. Long-term studies of alpine and subalpine plant communities, pollinator networks, stream chemistry, and snowmelt hydrology in the East River and Coal Creek watersheds inform interpretation of mining impacts on tundra biodiversity, mesic meadows, sensitive species such as roundleaf sundew (Drosera rotundifolia) in fens, and grouse populations on sagebrush winter range. RMBL's sediment core, gap-filling, and life-utility analyses help managers distinguish natural variability from anthropogenic change, making the laboratory an essential partner in any credible Colorado Review Process evaluation of the Mount Emmons project.

References

After Subsidence Mount Emmons (Drawings). →

AMAX Inc. — Mount Emmons. →

Antelope Creek Area Surficial Geology and Soils. →

Cabin Creek Area Surficial Geology and Soils. →

Effects (Comarc Design Systems subsidence analysis). →

Environmental Assessment Record — Raton Basin Coal Bed Methane Development. →

Mount Emmons Mining Project Environmental Impact Statement Chapter. →

Mount Emmons Schematic Alkali Creek Plan (Map). →

Mt. Emmons Project Area. →

Mt. Emmons Project Pre-Feasibility Report, 1998. →

RE: Comments for Scoping the Navajo Transmission Project. →

Scope of the Environmental Impact Statement on the Proposed Mount Emmons Mining Project, 1979. →

Soil Inventory Mount Emmons & Corridor. →

The Alternatives: Description of Activities Common to all Alternatives. →

The Scope of Environmental Impact Statement, Mt. Emmons, 1979. →

US Energy Corp. Annual Report 2006. →

Versatile Molybdenum. →

USEC

The Alternatives: Description of Activities Common to all Alternatives