The metal structures distributed in underground coal mine roadways can be equivalent to the receiving antenna to absorb electromagnetic wave energy and release the energy in the form of discharge sparks under specific conditions. The accumulated energy has the risk of igniting explosive gas. In order to solve the problem. the conditions of ignition of gas by discharge spark when the m... https://www.spidertattooz.com/Essie-Tea-Crumpets-0-5-oz-325-p15557/