Iron Ore Mining Method Mining Heavy Machinery
A underground method of mining iron ore where theoreis of moderate thickness 10 to 15 feet thismethodis not so open to criticism but when theorebodyis 20 to 50 or 100 feet thick and rather soft it has serious drawbacks in the great pillars oforewhich must be set apart for this purpose and in their tendency to crumble especially in the event of a creep or crush which follows in a