Short answers, pulled from the story.
104,895 coal miners have been killed in mine accidents in the United States since 1900. Ninety percent of those fatalities occurred in the first half of the 20th century. The deadliest year on record was 1907, when 3,242 miners died.
Surface mining is used when coal seams lie within roughly 200 feet of the surface; underground mining is required for seams at depths of 300 feet or more. Underground mining currently accounts for about 60 percent of world coal production, with longwall mining alone responsible for about 50 percent of underground output.
Black lung, or pneumoconiosis, is a chronic lung disease caused by long-term inhalation of coal dust that reduces life expectancy. In the United States, about 4,000 new cases are diagnosed every year, roughly 4 percent of the mining workforce annually. China records approximately 10,000 new cases per year.
China is by far the largest coal producer in the world. In 2019, China produced an estimated 3,692 million metric tons, out of a global total of 7,921 million metric tons. India, the United States, Indonesia, and Australia are the next largest producers.
Damps are buildups of hazardous gases in mines, a term likely derived from the German word Dampf meaning steam or vapor. Fire damp, mostly methane, explodes at concentrations of 5 to 15 percent. Black damp, a mix of carbon dioxide and nitrogen, causes suffocation. White damp contains carbon monoxide, which is toxic even at low concentrations.
Underground coal mining in Germany ended in 2018 when RAG AG closed its two remaining mines, Prosper Haniel and Ibbenbüren. The Bundestag had voted in 2007 to end coal subsidies by 2018 following EU regulations. Open pit lignite mining for electricity generation continues in Nordrhein-Westfalen and in the eastern German states.