Unlike Diamond or Gold, Coal is used for creating fires, fueling trains, and creating energy, rather then worn on rings or earrings. Due to this though, one wrong move and the entire mine shaft will burst into flames, creating a never ending fire. Coal is one of the most frequently used minerals, due to the need of it with large equipment and everyday house furnaces, making the industry similar to the gas industry. Coal mining is the most dangerous type of mining. The miners risk so much just accepting the call. The mine shaft walls could cave in, crushing everyone inside. Miners have to place up boards to support the walls they are mining, so when one wall isn't placed, the sturdiness of the mine could be compared to a jenga game with one block holding the entire tower. Since the equipment used to mine is extremely large and can move fast, collision is an extreme danger indicator as well. If the air is damp, or even the walls are a bit well electrocution is just as deadly as any other risk factor already stated. Along with all of that, miners have to watch out for chemical leakage. Hundred years ago, miners would take down an animal, usually a bird in a cage, while mining so they would become aware of a chemical leakage before it would become deadly so everyone could evacuate.