Asked | Open questions | Answered Points Date Pair Term / Answer given Level Status Gloss 4 Aug 17 '06 nor>eng Fjellhall disposal cavern pro closed ok 4 Apr 23 '06 eng>eng burst through the earth’s crust millions of years ago as molten magma. see below... pro closed no 4 Apr 23 '06 eng>eng Where concentrations are found at depth mining is underground using shafts, inclined roadways and tunnels. see exålanation pro closed no Asked | Open questions | Answered