CHARLESTON, W.Va. -- The number of coal miners working in West Virginia showed a slight drop during the second quarter of 2013, according to the latest data mine operators reported to the U.S. Mine Safety and Health Administration.MSHA's latest data, for the period from April to June, showed just less than 21,400 coal miners working at the state's mining operations. That's a drop of about 125 jobs over the first three months of the year, according to MSHA data.The MSHA data for the most recent quarter showed a reduction of more than 2,400 jobs over the same period in 2011.By law, mine operators must report employment and production data to MSHA every quarter. The figures may differ from state employment numbers, and from layoff figures that may not reflect workers who move from one mine to another.The latest figures show the continued impacts of coalfield layoffs fueled by a variety of factors and come as concern among industry officials about the future has increased in the wake of President Obama's announcement of plans for greenhouse-gas emission limits for existing power plants.Energy experts and industry analysts blame the decline of Appalachian coal in large part on cheap natural gas, competition from other coal basins, and the mining out of the easiest-to-reach reserves.For years, government and private forecasts have projected a decline in Southern West Virginia coal production, fueled by quality reserves being mined out and increasing pressure from giant surface mines in Wyoming's Powder River Basin.More recently, advances in natural gas drilling resulted in extremely cheap prices, prompting many energy producers to switch fuels. Additionally, new efforts by the U.S. Environmental Protection Agency to reduce toxic air emissions have forced some utilities to speed up plans to close older, inefficient coal plants that couldn't meet tighter standards aimed at protecting public health.Earlier this week, Moody's Investor Services said that it expects business conditions for the U.S. coal industry to remain depressed through next year.Moody's said it expects "further deterioration" following a major decline in coal's share of U.S. electricity and the historically low natural gas prices fueled by the revolution in shale gas drilling.In late July, investment bank Goldman Sachs warned "the window to invest profitably in new mining capacity is closing.""We believe that thermal coal's current position atop the fuel mix for global power generation will be gradually eroded by the following structural trends: 1) environmental regulations that discourage coal-fired generation; 2) strong competition from gas and renewable energy; and 3) improvements in energy efficiency," Goldman Sachs said in a July 24 report.Reach Ken Ward Jr. at firstname.lastname@example.org or 304-348-1702.