The Trump Administration has taken several actions intended to help revive the U.S. coal industry. Within its first two months, the Administration rolled back or began reversing several coal-related regulations finalized under the Obama Administration. For example, the Trump Administration repealed the coal valuation rule on August 7, 2017, effective on September 6, 2017. This effort was undertaken as three of the largest coal producers continued recovery from Chapter 11 bankruptcy, and occurred in the context of higher coal prices (making coal production possibly more profitable), lower inventories, and higher natural gas prices—factors that could lead to coal being more competitive as a fuel source for electricity generation. Coal will likely remain an essential component of the U.S. energy supply, but how big of a role will it play? As the Trump Administration is focused on reversing some of the Obama Administration's coal-related rules, congressional action in the 115 th Congress has primarily centered on assistance to distressed coal communities (e.g., H.R. 405 / S. 76 , H.R. 663 , and H.R. 1731 / S. 728 ) and coal miner health benefits (e.g., H.R. 179 / S. 175 , H.R. 323 , and H.R. 1613 ). There is also legislation proposing coal leasing reform ( S. 737 ), preventing new coal and other fossil fuel leasing on federal lands ( H.R. 2242 / S. 750 ), and preventing new self-bonding for coal projects ( H.R. 1819 / S. 800 ). The United States sits on abundant coal reserves and resources, but it also has an abundance of natural gas resources. Additionally, because of technical innovation and regulatory incentives, costs for renewable energy are declining, leading to a likely long-term growth trend in renewable energy capacity. Even though U.S. coal production remained consistent at over 1 billion short tons annually over the past two decades (until recently), coal is losing its share of the overall U.S. energy market, primarily to natural gas. Just a few years ago, coal production, consumption, and exports were at or near record levels, but 2015 and 2016 saw significant declines. One of the challenges for the industry is how to penetrate the overseas coal market, particularly for steam coal, to compensate for declining domestic demand. Domestic and global concerns over the potential environmental impacts from burning coal, particularly around carbon dioxide (CO 2 ) emissions and climate change, are leading to clean coal alternatives and the greater use of natural gas and renewables. There is also the domestic concern over job losses and long-term impacts within coal communities. If coal jobs do not come back in large numbers, what new employment opportunities could be created? At the global scale, some emerging countries see coal as the primary path to electric generation in the short term, while at the same time more developed countries such as Canada and those in Europe are moving away from coal and toward renewable energy. China, which currently consumes over 50% of the world's coal and is expected to remain the largest coal consumer over the long term, is seeking to implement a more balanced energy strategy as a response to the environmental impacts of burning coal. Beginning in the 1970s, U.S. coal operators were required to comply with numerous federal and state regulations including stream buffer rules, effluent guidelines, underground injection control, and siting and reclamation rules. As U.S. energy policy and environmental regulations are debated, there is ongoing congressional interest in the role of coal in meeting U.S. and global energy needs. The question may not be whether the domestic production of coal is here to stay but, rather, how much U.S. coal will be burned, what type (e.g., from which region), and under what regulatory framework. Coal mining is capital intensive, and coal prices (like other commodity prices) are volatile. The coal industry will be challenged to be profitable in the current environment whether or not the industry incorporates social and environmental costs. A McKinsey and Company report that was critical of the financial health of the coal industry questioned whether the industry could overcome long-term indebtedness and abundant low-cost natural gas supplies in order to compete in the global export market. This report reviews the historical trends (over the past 30 years) and recent developments in the U.S. coal industry, including coal development on federal lands, but does not cover the health, safety, and labor union issues associated with coal mining. (For more details on the health benefits issue, see CRS In Focus IF10616, Health Benefits for United Mine Workers of America Retirees , by John J. Topoleski.) For more details on environmental issues, see CRS Report R44150, The Office of Surface Mining's Stream Protection Rule: An Overview and CRS Report R44341, EPA's Clean Power Plan for Existing Power Plants: Frequently Asked Questions . Appendix A provides a primer on coal (including Table A-1 , which reflects more current production and consumption data published by the EIA; for the purposes of showing more disaggregated data for production and consumption, Table 1 and Table 4 in the text use EIA Annual Coal Report data). Appendix B provides selected coal production company profiles, and Appendix C provides a list of selected coal-related CRS reports that are not otherwise referenced in this report. The United States has the largest coal reserves and resources in the world. The Energy Information Administration (EIA) estimates there are about 255 billion short tons (Bst) of recoverable domestic coal reserves. The U.S. total demonstrated resource base (DRB) is estimated at about 477 Bst. Coal resource deposits are found in various regions in the United States (see Figure 1 ), with the dominant coal reserve owner being the U.S. government. EIA statistics show that more than half (55%) of U.S. coal reserves are located in the West, of which Montana and Wyoming together account for 43% of total U.S. reserves. About 70% of U.S. coal reserves are located in the top five producing states, which are Wyoming, West Virginia, Pennsylvania, Illinois, and Kentucky. The U.S. government owns about one-third, or 88 Bst, of U.S. domestic coal reserves, followed by Great Northern Properties Limited Partnership (20 Bst) and Peabody Energy Corporation (6.3 Bst). Altogether, the top three reserve owners account for about 44% of U.S. coal reserves. U.S. coal production had been strong since the 1990s (above or near 1 Bst per year until 2014), and reached its highest level of production in 2008 (1.17 Bst) before it declined precipitously in 2015 (see Table 1 and Figure 2 ) and 2016. EIA current data and short-term projections show coal production remaining under 800 million tons in 2017 and 2018 (see Table A-1 ). The prospects are not promising for a reversal of fortunes for U.S. coal mining in the long run, particularly for underground eastern coal, as lower-cost Powder River Basin (PRB) coal (with its extensive reserves) maintains its dominance and as Interior Region coal gains ground. Western coal, in general, has gradually risen from about 53% of U.S. production in 2000 to 61% of production in 2015, and is expected to retain a majority position at 51% through 2050, according to EIA's long-term reference case. Production from the Interior Region would gain from 18% in 2015 to 28% of total U.S. coal production by 2050. Long-term EIA projections show that coal production would fall below 600 million short tons (mst) per year under the reference case that includes the implementation of the Obama Administration's Clean Power Plan (CPP). Without CPP, coal production would remain relatively flat, at between 800 million and 900 million short tons per year through 2050. The trend in coal mining has been to improve labor productivity, or to make production more efficient, with the use of technology. There were sharp increases in labor productivity (more coal per man-hour) in the 1980s and 1990s, as labor productivity more than doubled from 2.74 average production per employee hour in 1985 to 7.02 in 2000, particularly at coal mines in the West (see Table 2 ). There is no indication that the coal industry will see a reversal of these production trends, even if there are some short-term gains in employment. Any employment gains would be starting from a historically low level. As shown in Table 2 and Figure 3 , coal mining employment declined from 169,300 in 1985 to 71,500 in 2000 (a 57% decline), then rose to a recent high of 86,100 in 2010 (as coal production was rising) before falling again to a historic low, 65,900, in 2015. A similar pattern was true for the number of coal mines, as the majority of the decline occurred between 1985 and 2000, when the number of coal mines fell by 55% (from 3,355 to 1,513) before declining further by 45% from 2000 to 2015 (from 1,513 to 834). As coal production was trending upward, reaching its peak in 2008, the number of coal mines declined dramatically (see Table 3 and Figure 4 ). Additionally, the number of coal mining firms has decreased in the United States, while the size of the average mine and output per mine have increased. If mines continue to close, particularly underground mines east of the Mississippi, and large-scale surface mines in the West stay more economical, then the impact on coal mine employment may continue to disproportionately affect eastern coal miners. Recently, however, overall employment losses among underground and surface mines have been similar. For example, from 2010 to 2015 employment losses in underground and surface mining operations were about 10,000 each (see Table 2 ).