coal mine, coalmine, mine, shaft, rockface, miners, cavern, colliery, cave, elevator shaft, ventilation shaft, drainpipe, trench, manhole, underground, stope, winze, ledge, crevasse, cliff, pit, bivvy, adit, cesspit, mineworker, ravine, crevice, chimney stack, crosscuts, tunnel, dungeon, slagheap, lodes, slag heap, quarry, precipices, firedamp, depths, rabbit hole, moiling, crag, sandpit, coal seam, serac, chimney, hatchway, mountainside, digger, rescuers, gasholder, fumaroles, pithead, gulch, catacomb, soakaway, spelunkers, piton, ore, spelunk, digging, stairwell, deathtrap, bedspring, flume, creek bed, plughole, dragline, coal miner, airing cupboard, waterfall, staircase, rubbish dump, coalfield, septic tank, trapdoor, oilwell, excavator, hogback, peat bog, posthole, woolshed, scree, surface mine, abyss, spruit, corrie, orchestra pit, tramming, abseiling, burrow, travelator, koppie, washhouse, sarcophagus, sandhog, weir, muskeg, dolerite, borehole, drainage ditch, boulder, opencast, burrows, culvert, gutters, alleys, cellar, cesspool, chute, courtyards, crack, curtain, ditch, drifts, drips, dugout, fissures, floor

excavation, hole in the ground