First of all, coal mining is one of the most water-intensive industries, often requiring 2.5 tons of water for every ton of coal produced, creating three to six billion tonnes of water waste per year. . This can affect the water table by significantly increasing its pH, and it significantly changes groundwater levels (due to the amount of water needed to refine coal). Additionally, mining releases burned coal into the air which combines with oxygen to form SO2. This SO2 can then mix with moisture in the air to form acid rain which can harm the environment. Of course, coal mining not only affects the environment around us, it can also be disastrous for coal mine workers. One of the worst events in history occurred in 1970 in West Virginia, when a coal dust explosion at the Upper Big Branch Mine killed 29 out of 31 workers. The company that owned the mine was forced to sell it to a competitor and pay $209. After this event, coal prices soared for over 10 years, before falling again (as shown in the chart on the right). Other events like this have happened all over the world and still pose a constant threat lurking behind the backs of every miner.