WETHERSTONES CONGLOMERATE.

Evening Star, Issue 21091, 2 May 1932, Page 1

WETHERSTONES CONGLOMERATE.

TO THE EDITOR. Sir, —Your last report of tho operations of the company working on this great auriferous deposit makes mention of the use of explosives. I think the general opinion amongst mining people is that there is little hope of success until a method is devised for mechanically milling the conglomerate at a cost commensurate with its low ore value. The Otago Gold Mining Company used dynamite for breaking down the cement wash over forty years ago, but found the wash then had to go through the crushers, as the utmost

pulverisation is necessary before ths small particles of gold are liberated. Following the use of explosives, it ia extremely unlikely that a sufficiently fine crushing can be obtained by gravity fall into riffle bars. Such a' method would not present nearly so effective a crushing force as was possible by the old method of breaking down under hydraulic pressure, and this was insufficient. My personal opinion is that a system based on the modem rotary grinders used in cement works may provide a solution of the problem. — I am, etc., Millington. May 2.