d) lt is a underground mining method used for small rich ore bodies. Answer:(d) : Long wall method is generally employed for: a) Copper ore mining. b) lron ore mining. c) Coal mining. d) Gypsum mining. Answer:(c) : The width of the ore body which can be economically mined is: a) Stopping width. b) Assay width. c) Actual width. d) Grady width. Answer:(a)