Coal ash, as commented before, is a major problem since it is usually dumped into ponds that pollute the air and the ground water, creating serious illnesses. In the future man may clean up and mine the coal industries historic waste rather than mining then incinerating coal to generate electricity. It has been found that in addition to dangerous elements found in coal ash there are also 17 metallics found at the base of the periodic table in coal ash waste. These elements used, for example in iPhones, can be “mined” from coal ash more easily than from the earth. This would be a frugal way to get rid of coal ash and provide needed materials for manufacturing essential equipment.
Source – Sierra

Earth Savers is a series of quick conservation notes from Christ & St. Luke’s Episcopal Church Caring for Creation