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Frequent Questions

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This page provides various links to non-EPA Web sites that provide additional information about the Coalbed Methane Outreach Program (CMOP). Read more about EPA's exit disclaimer » Exit EPA

  1. Why is EPA concerned about coal mine methane?
  2. What is the difference between coalbed methane and coal mine methane?
  3. How does CMOP work to reduce methane emissions?
  4. What is CMOP's role in promoting international coal mine methane projects?
  5. How is methane emitted from coal mines?
  6. How much methane is emitted from coal mines?
  7. What are the uses for coal mine methane?
  8. How much methane is captured and recovered from coal mines? Where are the projects?
  9. Where are the best opportunities for developing coal mine methane projects in the U.S.?
  10. What is ventilation air methane and how can it be used?
  11. What is abandoned mine methane?
  12. How do I find out about international activities in coal mine methane project development?
  13. How do I keep in touch with CMOP and learn about new developments?
  14. What is global climate change and why should we be concerned about it?

1. Why is EPA concerned about coal mine methane?

Methane is the second most important greenhouse gas after carbon dioxide. In fact, methane is over 20 times more potent than carbon dioxide (CO2) on a mass basis over a 100 year time period.

Coal mine methane (CMM) represents wasted emissions to the atmosphere, while capture and use of CMM has benefits for the local and global environment.

More information about methane »

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2. What is the difference between coalbed methane and coal mine methane?

Coalbed methane refers to methane that is found in coal seams. It is formed during the process of coalification, the transformation of plant material into coal. Coalbed methane is also known as "CBM," or virgin coal seam methane or coal seam gas. It is widely considered an "unconventional" source of natural gas. In the U.S., coalbed methane is a valuable resource that accounts for about 10% of total U.S. natural gas production annually.

More information on CBM production in the U.S. » Exit EPA

Coal mine methane (CMM) refers to methane released from the coal and surrounding rock strata due to mining activities. In underground mines, it can create an explosive hazard to coal miners, so it is removed through ventilation systems. In abandoned mines and surface mines, methane might also escape to the atmosphere through natural fissures or other diffuse sources. Like CBM, coal mine methane is a subset of the methane found in coal seams, but it refers specifically to the methane found within mining areas (e.g., within a mining plan), while CBM refers to methane in coal seams that will never be mined. Because CMM would be released through mining activities, recovering and using CMM is considered emissions avoidance.

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3. How does CMOP work to reduce methane emissions?

CMOP is engaged in numerous domestic and international outreach efforts.

In the U.S., CMOP works cooperatively with the coal mining industry to support project development, overcome institutional, technical, regulatory, and financial barriers to implementation, and communicate the benefits of CMM recovery.

Specific activities include:

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4. What is CMOP's role in promoting international coal mine methane projects?

CMOP continues to develop partnerships, fund grants, and engage in international outreach to promote CMM recovery and reduce CMM emissions globally in support of the Global Methane Initiative Exit EPA. We have established information clearinghouses in several countries, including China, the Russian Federation, Ukraine, Poland, Kazakhstan, and India.

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5. How is methane emitted from coal mines?

There are three primary sources of CMM:

Other, more minor sources of methane from coal mines include surface mines and post-mining activities (coal continues to emit methane as it is stored in piles and transported).

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6. How much methane is emitted from coal mines?

Globally, coal mines emit over 500 million metric tons of carbon dioxide equivalent annually (over 28 billion cubic meters annually), or about 6% of total anthropogenic methane emissions.

In 2011, U.S. coal mines emitted about 62 million metric tons of carbon dioxide equivalent. Between 1994 and 2005, U.S. emissions decreased by over 20%, in large part due to the coal mining industry's increased recovery and utilization of drained gas. Between 2005 and 2011, emissions and the amount of drained gas utilized both increased by around 10% due to increased production.

China leads the world in coal mine methane emissions with nearly 300 million metric tons CO2E in 2010 (over 20 billion cubic meters annually). Other leading emitters are the U.S., Ukraine, Australia, the Russian Federation, and India.

2010 Global Coal Mine Methane Emissions

bar chart showing 2010 Global Coal Mine Methane Emissions

More information about CMM »
More information about U.S. CMM emissions »
More information about international CMM emissions (PDF) » (29 pp, 416K, About PDF) Exit EPA

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7. What are the uses for coal mine methane?

Technology is readily available to recover methane (CH4) — the major component of natural gas — from coal mines. Specific coal mine methane (CMM) end-uses depend on the gas quality, especially the concentration of methane and the presence of other contaminants.

Worldwide, CMM is most often used for power generation, district heating, boiler fuel, or town gas, or it is sold to natural gas pipeline systems.

CMM can also be used in many other ways:

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8. How much methane is captured and recovered from coal mines? Where are the projects?

In 2011, U.S. coal mines recovered and utilized over 41 billion cubic feet of coal mine methane. Nearly all of this gas was sold to natural gas pipelines. Between 1994 and 2005, U.S. coal mines reduced total U.S. coal mine methane emissions by over 20% largely due to their increased recovery and use of drained gas.

More about coal mine methane recovery projects in the U.S. (PDF) » (207 pp, 1.6MB)

Globally, as of 2012, , there are over 200 operating recovery and utilization projects in about 12 countries at active or abandoned coal mines and more than 30 more in development. Collectively these projects will mitigate over 16.8 billion cubic meters of methane each year (over 239 million metric tons of carbon dioxide equivalent).

More about global coal mine methane capture and recovery » Exit EPA
More about international coal mine projects » Exit EPA

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9. Where are the best opportunities for developing coal mine methane projects in the U.S.?

CMOP has identified about 50 active underground coal mines in the U.S. that have significant gas levels that may make them promising candidates for project development. As of 2011, about 20 of these mines have degasification (drainage) systems in place.

More information about candidate coal mines (PDF) » (207 pp, 1.6MB)

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10. What is ventilation air methane and how can it be used?

Methane is an explosive gas that is a hazard to underground miners. To ensure mine safety, fresh air is circulated through underground coal mines using ventilation systems to dilute in-mine concentrations of methane to levels well below explosive levels. These concentrations are regulated by mine safety authorities in each country. Typically, methane concentrations in ventilation air range from 0.1 percent to 1.0 percent.

Ventilation air methane (also known as VAM) refers to the very dilute methane that is released from underground mine ventilation shafts. VAM represents over half of all coal mining emissions in the United States and worldwide. With few exceptions, it is simply released to the atmosphere.

It is technically possible to convert the dilute methane in ventilation air to useful energy. The economic feasibility of these projects on a commercial scale is being demonstrated.

The high volumetric flowrate and low concentrations of ventilation air methane make it challenging to capture and utilize cost-effectively. Technologies to capture and harness the energy resource of VAM are currently being developed, demonstrated, and commercialized.

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11. What is abandoned mine methane?

When coal mines are no longer operated to produce coal, they are known as closed (or "abandoned") mines. Even though active mining no longer occurs, these closed mines can still produce significant methane emissions from diffuse vents, fissures, or boreholes. This methane can be deliberately extracted and used to generate power or for other end uses.

There are several thousand abandoned coal mines in the U.S. Of these, EPA has identified some 400 abandoned mines that are considered "gassy" and has developed profiles of successful projects at abandoned mines and mines that may be good candidates for project development.

Methane Emissions from Abandoned Coal Mines in the U.S.: Emission Inventory Methodology and 1990-2002 Emissions Estimates (PDF) » (90 pp, 2.0MB)

EPA developed a methodology to estimate fugitive methane emissions from abandoned mines. This methodology is now incorporated in the 2006 IPCC Guidelines for National Greenhouse Gas Inventories. Exit EPA

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12. How do I find out about international activities in coal mine methane project development?

CMOP is actively engaged in implementing the international Global Methane Initiative, Exit EPA a voluntary initiative to reduce methane emissions from four key sectors: agriculture, coal mining, landfills, and oil & gas systems. The Partnership focuses on near-term methane recovery for use as a clean, profitable energy source.

More information about the GMI Coal Subcommittee activities » Exit EPA
More information about CMOP's international activities »

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13. How do I keep in touch with CMOP and learn about new developments?

Join the CMOP Network! As a Network member, you'll receive our quarterly newsletter and weekly email updates. If you choose, you can also be listed as a contact on our network contact list.

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14. What is global climate change and why should we be concerned about it?

For more information, please visit EPA's Climate Change website.

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