Ключевые слова: ash, background, bituminous, black coal, burning, burnt, carbon, central heating, charcoal, coal, coal burning, companies, cost, cube, dark, dirty, ecology, energy, environment, exploitation, extract, fire, fuel, gas, graphite, heat, industrial coal, industry, lignite, manufacturing, material, metallurgical, mine, miner, mineral, natural, pile, power, power station, rock, smoke, stone, stove, surface, texture, textured, tiled, wealth, wood, worker,