PDF versionPDF version

Coal is a carbon-rich rock formed from plants that grew millions of years ago. Coal is a major source of electricity in the United States and the largest source of energy for electricity generation worldwide.


A coal-fired power plant in Westport, Kentucky on the Ohio River. Image Copyright © Michael Collier.

Coal is a rich source of energy formed from plants that grew in swamps tens to hundreds of millions of years ago. The plants were buried deeply under younger and younger layers of dirt and rock, heated, and compressed into a carbon-rich rock.[1] Burning coal releases more carbon dioxide per unit of energy produced than any other fossil fuel.[2]   Read more

Frequently Asked Questions

Latest News

Mammatus clouds that are usually associated with thunderstorms.
August 24, 2018 Pursuant to President Donald Trump’s executive order (E.O. 13783) promoting energy independence and economic growth, the Environmental Protection Agency (EPA) proposed a new rule on August 21 to reduce greenhouse gas (GHG) emissions from existing coal-fired electric utility...
The White House
August 1, 2018 Andrew Wheeler, the acting administrator of the Environmental Protection Agency (EPA), appeared before the Senate Committee on Environment and Public Works on August 1 to discuss the EPA’s priorities going forward under President Donald Trump. Wheeler assumed his current position...
Nuclear power plant, Czech Republic
June 12, 2018 The Senate Committee on Energy and Natural Resources held a formal oversight hearing for the Federal Energy Regulatory Commission (FERC) on June 12, 2018, with all five commissioners present for the first time in a decade. FERC is responsible for regulating the interstate transmission...
Power lines. Image Credit: U.S. Department of Energy
January 23, 2018 The Senate Energy and Natural Resources Committee held a hearing on January 23 that underscored concerns surrounding the reliability and resiliency of the electrical power system, particularly under certain weather conditions, such as the deep freeze or bomb cyclone that the U.S....
Nuclear power plant, Czech Republic
January 8, 2018 On January 8, the Federal Energy Regulation Commission (FERC) rejected a proposal that was submitted by Secretary of Energy Rick Perry in September 2017 to subsidize the operating costs of coal and nuclear power plants, since the rule did not satisfy certain statutory standards....
Excavator mining
May 25, 2017 The House Natural Resources Subcommittee on Energy and Mineral Resources held a legislative hearing on a discussion draft of the Community Reclamation Partnerships Act (H.R.__) to be introduced by Representative Darin LaHood (R-IL-18). This legislation would streamline efforts to clean...
Nuclear power plant, Czech Republic
February 16, 2017 Rep. Keith Rothfus (R-PA-12) introduced legislation (H.R.1119) to modify existing regulations applying to coal-refuse-to-energy power plants on February 16. The bill acts to exempt these specific power plants from emission standards required under the Environmental Protection...
#MapOfTheDay! Check out this interactive map of Iowa coal mines from @iowadnr
#MapOfTheDay! Today the Critical Issues Program (@AGI_GeoIssues) shared an interactive map of coal mines in Iowa from the Iowa Department of Natural Resources (@IowaDNR), which you can find at For information about coal mining, check out our Coal Basics.
Excavator mining
August 9, 2016 The Department of the Interior’s (DOI) Office of Surface Mining Reclamation and Enforcement (OSMRE) has issued guidance suggesting that states move away from accepting self-bonding, where companies use their current financial health as collateral to guarantee reclamation of lands...
June 22, 2016 The White House Council of Economic Advisers (CEA) released a report entitled, “The Economics of Coal Leasing on Federal Lands: Ensuring a Fair Return to Taxpayers”. This report is part of a larger ongoing review of the federal coal leasing program – the first such review since the...

Case Studies & Factsheets

Screenshot of the USEITI case studies showing the Boone, Logan and Mingo counties case study highlighted
U.S. Department of the Interior

The U.S. Department of the Interior's Office of Natural Resources Revenue, Information and Data Management has produced a series of case studies on extractive industries across the United States, focusing on coal, copper, gold, iron, natural gas, and oil. The case study on coal mining in West...

Screenshot of the USEITI case studies showing the Campbell County case study highlighted
U.S. Department of the Interior

The U.S. Department of the Interior's Office of Natural Resources Revenue, Information and Data Management has produced a series of case studies on extractive industries across the United States, focusing on coal, copper, gold, iron, natural gas, and oil. The case study on coal mining in...

Fig. 1. Exposure of sandstone capping an economic coal bed. Credit: J. Shaulis, Pennsylvania Geological Survey

Defining the Problem Despite Pennsylvania’s long history as a major coal producer, information on the coal geology (Fig. 1), remaining resources, and extent of past mining is not available for many areas of the state. Such information is critical for present and future coal exploration and...

Geological Surveys Database Publications

1977, Arizona Geological Survey

-------------------------- --------------------------- ------------------------ ------------------------------ ---------------------- -------------------

1979, Arizona Geological Survey
Carboniferous rocks in Arizona are represented by marine and continental deposits ranging in thickness from 0 to 1,100 m. Mississippian marine strata, consisting largely of cliff forming high-purity limestone, are overlain disconformably by thicker Pennsylvanian strata containing, besides carbonate...
1948, Florida Geological Survey

-------------------------- --------------------------- ------------------------ ------------------------------ ---------------------- -------------------

2016, Arizona Geological Survey
The Inspector General of the U.S. Department of the Interior issued a "Final Report - Inspection of Scientific Integrity Incident at U.S. Geological Survey (USGS) Energy Geochemistry Laboratory, Report No. 2016-EAU-010," on June 15, 2016, that concluded a chemist at the USGS Energy...
2016, Arizona Geological Survey
The Arizona Geological Survey (AZGS) is one of the most innovative, entrepreneurial, and highly-regarded Surveys in the nation, with a growing portfolio of national and international programs and influence. AZGS scientists are internationally recognized leaders in cyberinfrastructure and data...
2015, Arizona Geological Survey
This past year marked a major milestone for AZGS. The 4-year,
2014, Arizona Geological Survey
In this, our 125<sup>th</sup> anniversary year, we are celebrating the efforts of hundreds of geologists and geoscientists to understand Arizona's remarkable geology and apply that knowledge to making our lives safer and richer. All told, AZGS and its predecessor agencies have...
2013, Arizona Geological Survey
For the second year in a row, the project has received "good" or "outstanding" review comments during the annual sponsor peer review. Each reviewer scored the project as "outstanding" the highest possible mark for relevance and impact of research. Comments include...
2012, Arizona Geological Survey
Kelsey Boltz has been a registered mining engineer and geologist in Arizona since the mid 1960s. A 1953 graduate of the Colorado School of Mines, he founded Colamer Corporation and Nuclear Dynamics, both companies active in the uranium industry in the Grants Uranium Region of New Mexico in the...
2012, Arizona Geological Survey
These photographs were mostly taken from the ADMMR Mining collection, records on mineral resource exploration and mining in Arizona from late 1800s to the early 2000s. Photographs principally relate to a mineral locality reported in the Arizona Mineral Industry Location System. Photographs titled...