ABSTRACT
Asminersdig,theycontinuallyreshapetheundergroundlandscape.Every cutchangestheimmediateshapeofthewalls,floor,androof(ceiling)ofthe mine.Asminersremoverockfromtheface,pressuresfromtheoverburdenthemassofmountainabovetheimmediatemineroof-producesubtle changesintherockstrata.Iftherockitselfisunstableorifminersfailtosupportthisrock,thesechangescanproducesuddenandviolentfallsofrockthat maycrushminerswithoutwarning.Tinycracksintherockmayalsoliberate methanethatcanburnasalayerofblueflameaboveminers'heads.Ifmines arenotproperlyventilated,ifminersdonotreplacetheirpicksfrequently,if cuttingpickshitthehardlayerofrockratherthanthesoftcoallayer,ifelectricalequipmentsparks,orifminersincreasetheforceofthecuttoincrease production,frictionalheatproducedbythecuttingpickcanignitemethane
The critics say further that mining is a perilous occupation to pursue because the miners are sometimes killed by the pestilential air which they breathe; sometimes their lungs rot away; sometimes the men perish by being crushed in masses of rock; sometimes, falling from the ladders into the shafts, they break their arms, legs, or necks; and it is added there is no compensation which should be thought great enough to equalize the extreme dangers to safety and life.4
