Mine safety in coal mines, which in turn can initiate more extensive coal dust explosions. For this reason, rock dusts such as limestone dust are spread throughout coal mines to diminish the chances of coal dust explosions as well as to limit the extent of potential explosions, in a process known as rock dusting. Coal dust explosions can also begin independently of methane gas explosions. Frictional heat and sparks generated by mining equipment can ignite both methane gas and coal dust. For this reason, water is often used to cool rock-cutting sites. Miners utilize equipment strong enough to break through extremely hard
Submarine mines in United States harbor defense these mine control panels, plus many more related rack-mount devices for controlling the casemate's generators, inverters, and battery systems. The mines could be fired in three ways, listed here in order of tactical preference: Delayed contact fire was preferred because it was thought that the mine would first be dragged underneath the target and then fired after a few seconds' delay, once it had had the chance to contact a more lightly protected portion of the target's bottom. This type of fire required the casemate troops to hear the bell and see the accompanying signal light that indicated when a