Ключевые слова: big, blue sky, bucket, coal, coal mine, digger, digging, dirt, dirty, energy, engineering, environment, equipment, excavation, excavator, exploitation, fossil, fossil fuel, geology, giant, heavy industry, huge, industrial, large, machine, machinery, mine, mining, nature, opencast, operations, outdoors, pit mine, place of work, power, production, quarry, quarrying, vertical,