As of 2012, there were 24 active coal mines (15 underground and 9 surface) in Illinois which produced 48,486 thousand short tons of coal in 2012, or about 5% of the United States total coal production (Source: Coal Data, US Energy Information Administration). Additional Illinois coal mining data are available from the Illinois State Geological Survey. Water is used in mining and processing coal to cool or lubricate equipment, for dust suppression, process to fuel grade coal, and to revegetate after mining. The US Department of Energy estimated in 2006 that total water use for coal mining in the United States is 70 to 260 million gallons per day (Source: Energy Demands on Water Resources: Report to Congress on the Interdependency of Energy and Water, US DOE).
In 2012, coal was used for about 37% of the 4 trillion kilowatt-hours of electricity generated in the United States, and about 81% of the coal produced in the U.S. in 2012 was used to produce electricity. In 2012, Illinois consumed 48,509 short tons for electric power generation, or about 6% of the U.S. total used for that purpose. (Source: Coal Data, US Energy Information Administration). Impacts of coal-burning include emissions that have an impact on water. About 2/3 of the sulfur dioxide and 1/4 of nitrogen oxides causing acid precipitation comes from burning fossil fuels, such as coal, for electric power generation (Source: What is Acid Rain, US EPA). Lakes and streams are affected if they lack the capacity to neutralize the acid (Source: Effects of Acid Rain, US EPA). Coal-burning power plants are the largest human-caused source of mercury emissions to the air in the United States, accounting for over 50 percent of all domestic human-caused mercury emissions (Source: 2005 National Emissions Inventory). Mercury in the air settles into water or onto land where it can be washed into water (Source: Mercury, US EPA).
Coal ash from coal combustion contains contaminants including mercury, cadmium, and arsenic. It is stored in liquid form in surface impoundments or solid form in landfills. Contaminants can leach into groundwater and impoundment failure has caused major damage to surface water resources (Source: Coal Combustion Residuals - Proposed Rule, US EPA; Final Rule published in 2015).