GREAT DEPTH IN MINES.

Manawatu Standard, Volume XLIV, Issue 1075, 23 July 1924, Page 10

GREAT DEPTH IN MINES.

DOWN FOR OVER A MILE. Mines continue to sink deeper, quite a number having bored the earth to more than a mile, though the St. John del Rey, in Brazil, advancing at an average of 150 feet a year, still holds the record. Its latest announced vertical depth was 6726 foet, but, as it- is entered by an adit intersecting the shaft 324 feet below its top, the actual depth may be placed at 6400 feet. Ol' the several deep shafts of the Kolar gold fieldSj in India, one is stated by Indian Engineering to reach a vertical depth of 6140 feet. South Africa also has deep mines, and the Village Deep has been sunk to 6100 feet in 1921, wliilo another is to go eventually beyond 7000 feet. Tamarack 6, the deepest mine in the United Statos actually approaches nearer the earth’s centre than Brazil’s deepest, as, although. only 5308 feet, its bottom is 4100 feet below sea level,- wliilo that of the St. John del Rey is only 3982. An interesting fact is that the ore of the St. John del Rev mine seems to glow riches with depth, and the reported return per ton of ore was nearly 40 per cent, greater in 1922 than in 1912.