Miners use em all the time, it's the only way to go in the real dark. Ever seen absolute darkness? Ever seen absolute white? Working in Homestake Gold Mine in 76/77 (it was its hundredth year of operations then) I saw quite a few sights. One happened to be a moss covered stope, absolute white moss(never seen even a glimmer from the sun). When I turned off the light, it was absolute darkness. When I flipped the switch, it changed instantly to absolute white. Cool huh : D
Anyhow, the company issued the hardhats and lights, batteries etc. After each shift we'd return our badge to the board(everybody had a brass number that we'd remove from the board going in, and return to the board going out) and our battery to the charger(in it's particular place). If you left there without doing both, they'd have to come find you(sure better not mess up there, and let em find you at home or in a bar nope)
These lights were cool, and not that hard to wear, fit right on front of the hard hat, and had a switch that went from a beam to a wide angle to off. I know for sure they'd last at least a solid 12 hours
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