The incident, described as a rock wall collapse, occurred underground ... “Two of the men were outside the mine upon our arrival and crews were working the free the third man,” said Justin ...

a particularly destructive form of mining in which large machines shear walls of coal, leaving vast, empty expanses in their wake. Land above those empty caverns sinks, causing what is often ...

(iStock) Alberta's energy regulator is examining practices at a coal mine in the province after three "instabilities" in its rock walls — including one weeks ago that partially buried a large ...

“More times than not, you’ll have this set up,” said Bob Seitz, engineering manager for CCU, pointing to the exposed walls in the mine ... soil and rock removed to reach coal seams ...

Alberta’s energy regulator is examining practices at a coal mine in the province after three “instabilities” in its rock walls — including one weeks ago that partially buried a large piece ...

In surface mining, coal companies use explosives and heavy equipment to move earth and rock to uncover coal seams ... includes grading to eliminate sheer walls created during mining — called ...

Alberta’s energy regulator is examining practices at a coal mine in the province after three “instabilities” in its rock walls — including one weeks ago that partially buried a large piece ...