guys/gals.....this old dog was reading an august, 1997 Discovery magazine article (page 25) about MCO this arvo & found a great explanation as to why the old timers employed a "rape & pillage" mining strategy at the MS mine, that left intact an abundance of remnant gold ore.
the reason, according to the article, was due to the gold processing technology available at the time.
"Average historical mining grades were over 22g/t, with the gold ore extracted from u/g never falling below 11.6g/t as the gold processing technology of the day could not profitably extract any ore with a lower grade.
This has left large volumes of remnant ore which could be mined".
these days the processing technology has gone forward in leaps & bounds. so much so that in tests carried out in 2007 by MCO a 99% recoveries rate was achieved.
At a coarse 250microns crush, Morning Star found that the bulk samples returned up to 88% gravity gold recoveries through the first crush with up to 98% total recoveries after a short period of leaching (8 hours) and greater than 99% recoveries after 24 hours.
therefore all the remnant ore the old timers left behind is ours for the taking.
so the Gap Zone from levels 7 - 15, that WMC(GMA) only drilled a few holes into, was left intact due to the 1939 bushfires, & the remnant ore was left thruout different levels in the mine due to recovery technology only being able to profitably process ore at grades above 12g/t.
p.s. of course, remnant ore is only a part of all the gold ore intact in the mine.
MCO Price at posting:
13.0¢ Sentiment: Buy Disclosure: Held
