Aspen, Colo., like many Western cities, is working hard to cut its greenhouse-gas emissions. The ski resort gets three-quarters of its electricity from renewable sources, provides free mass transit, and sells “Canary Tags” to fund local emissions-cutting projects. One possibility for such projects is at coal mines, three of which lie 50 miles southwest.

Coal mines are a global-warming double whammy. Each ton of coal burned emits about three tons of carbon dioxide. Then there’s the methane that seeps from underground coal seams — it packs 21 times the climate-changing punch of CO2. To neutralize it, the methane can be burned off, or, better still, used to generate power. The resulting emissions reduction can then be sold to a city or business that wants to offset its contribution to global warming.

Aspen would have liked to work with the local West Elk Mine, but legal obstacles made that impossible. So it went to the Aberdeen coal mine in Utah and helped set up a project to pipe methane, only to find that an independent auditor wouldn’t certify the project. The city gave up. Yet at some 40 active and abandoned underground coal mines in the West, 20 billion cubic feet of methane escapes into the atmosphere each year, the emissions equivalent of 1.9 million cars. Several knotty issues plague attempts to capture those emissions — even as methane-recovery projects flourish east of the Mississippi.

For safety, all underground coal mines in the U.S. exhaust huge amounts of diluted methane. Some, including the West Elk, produce so much of the explosive natural gas that they also drill drainage wells to vent it. The West Elk puts some of its methane — about 170 million cubic feet each year — to work heating ventilation air on site. But now the mine plans to send much more methane into the air. Last fall, St. Louis, Mo.-based Arch Coal got an expansion permit from the Forest Service that will allow it to drill 168 new drainage wells to vent methane — 7 million cubic feet daily for the next 12 years, enough to heat up to 34,000 homes annually. At today’s prices, that gas would be worth about $21 million per year.

In early October, environmental groups filed a lawsuit asking federal agencies to withdraw the permit, citing the waste of natural gas and the significant contribution to global warming. Venting the methane from existing coal mines is especially ironic when energy companies are drilling for natural gas on relatively undisturbed public lands from Wyoming to New Mexico. It’s “environmental crime and economic insanity combined,” says energy consultant Randy Udall.

The biggest impediment to coal methane capture in the West is the fact that most mines are located on federal land. A mining company with a public-land lease can drill methane drainage wells, but cannot sell or use the methane unless it also leases or owns the natural gas rights, according to the Bureau of Land Management. However, a July ruling by the Interior Board of Land Appeals found that the vented methane at the Aberdeen mine “is not an oil and gas deposit subject to leasing.” Says Pamela Franklin, director of the Environmental Protection Agency’s Coalbed Methane Outreach Program, “No one knows what the exact process is.”

The BLM considered auctioning natural gas leases in the West Elk’s expansion area in August. Part of it is a Forest Service inventoried roadless area, though, and with the Roadless Rule back in legal limbo, the BLM withdrew the parcels, says Forest Service spokeswoman Lee Ann Loupe. Environmentalists find the lack of interagency coordination frustrating. “The Forest Service is hiding behind the BLM’s skirts,” says Udall. Lack of infrastructure is another problem: At many Western mines, it’s 15 or 20 miles to the nearest pipeline, and methane must be purified and compressed before entering the flow.

The second-best alternative to piping the methane or using it on-site is burning the gas at the well. Flaring or oxidizing converts methane to carbon dioxide and water, significantly decreasing its global warming potential. Oxidizing technology is used at one mine, but flaring is not being done anywhere in the U.S. Coal-mine flaring technology is unproven, according to the Mine Safety and Health Administration, although Australia and the United Kingdom use it safely. The bigger hindrance to either flaring or oxidizing is lack of a developed market for carbon offsets, says Franklin: “The voluntary carbon credit market is the only incentive, and it’s still nascent.”

Farther East, methane capture has been much more successful. Methane recovery projects at active and abandoned underground coal mines in Alabama, Ohio, Illinois, Virginia, West Virginia and Pennsylvania capture at least 46 billion cubic feet of methane annually, enough to heat 600,000 homes.

Several factors account for the difference. In the East and Midwest, pipelines and infrastructure are generally close to mines. Natural gas prices are higher: Even a difference of a couple of dollars per thousand cubic feet is enough to make projects more economically rewarding. Most importantly, the mines are usually on private land with private mineral rights. Laws vary from state to state, but the process for obtaining rights is well established.

For methane-rich coal mines in Utah, Colorado and New Mexico, regulatory obstacles need to be cleared before those mines can start trimming their greenhouse-gas emissions — and stop wasting energy. The EPA has pledged to work on the problem with the other agencies involved, but no specific plans exist. A change in attitude is needed, too: “Some (Eastern) coal companies now think of themselves as energy companies, and they make a lot of money from gas,” says Franklin. “Coal companies in the West think of themselves as coal companies. Branching out into different resources is not something they think of culturally.”