DIAMONDS TO CUT HARDEST ORES

Dominion, Volume 30, Issue 157, 31 March 1937, Page 11

DIAMONDS TO CUT HARDEST ORES

Magic Cutting Wheel

“In a London office,” wrote a correspondent in the London “Observer” recently, “I had demonstrated to me a diamond-studded ore-cutting wheel which seems destined to revolutionise mining methods in South Africa, and even to have a profound influence on quarrying and mining in England.

“The wheel at first sight appears to be a comparatively simple piece of metal work. Actually some of the wheels shown to me were ‘gold cutters,’- with the metal—iron or steelimpregnated, by heating and hydraulic treatment, with the powder of small diamonds so that a hardness is created that no known surface can resist. “In a recent test in South Africa a ‘gold cutter’ of this type, mounted exactly on the same principle as a coalcutter, revolved at 4000 revolutions a minute and cut through quartz as though it bad been cheese. “To extend the analogy, in proof of the qualities of the cutter, wafers of porcelain, ‘pencils’ of plate-glass, cubes and sticks of Scottish and Cornish granite, and layers of Scottish whinstone, which had been sliced with the ease of a bacon-cutting machine, were produced for my inspection. “The cuts were clean and straight, for all the world as if the resistance had been merely that of a lump of butter.

“With this invention it is hoped to cut out the gold-bearing banket of the Rand into slices or blocks, and if success is gained when large-scale operations have been attempted—small-scale operations have been signally successful—the saving in costs and life and limb will be incalculable.

“Drilling and blasting will possibly be superseded; .the risk of dreaded ills, such as phthisis, will be substantially reduced.

“The invention is British. It is owned by the Diamond Development Company, which is associated with the Diamond Corporation, controllers of all the world’s diamond output, and those associated with it include Sir Ernest Oppenheimer and. Mr. Jack Joel. The pioneer machine was built in cooperation with a Glasgow engineering firm, and models of it are now being made at a factory near Antwerp.

“The cutting wheels shown to me were of 3in. and 6in. sizes. Larger ones are made in segments, after the diamonds have been crushed and ‘oiled’ into the metal, and then fixed on the operating shaft. “Tungstone carbide, harder than any steel, and incapable of being effectively ground, can be sliced in a few seconds, leaving a fine, mirror-like surface, “Demonstrated on churt, the hardest rock on the Rand, the machine astonished Government officials and mining engineers. It literally cut this rock into wafers with the greatest of ease.”