I wish to point out one error which somehow crept into "Felderhof's new life after Bre-X" (T.N.M., Dec. 31/12-Jan. 6/13). This concerns the comment in brackets: "using gravity concentrate and not alluvial gold, contrary to published technical reports.”
There are no technical reports that state that the gold had an alluvial origin. This is pure speculation by Mr. Farquharson, a mining engineer, not a geologist, geochemist, geophysicist and foremost not a petrologist.
Gravity test work was done both on 27 bulk sample by Ore Test in the U.S. and by Normet. Petrologists involved were Dr. Martha Swartz and Dr. Roger Townsend. Neither of them identified alluvial gold. Dr. Roger Townsend studied 10 coarse gold grains. Metallurgically speaking, this refers to any gold whose particle size exceeds 100 microns or 0.1mm. The size range at Busang was established at 40 to 170 microns. At Kelian the range was between 20 to 240 microns.
Strathcona submitted over 100 gold grains from one reject sample which assayed 17.6 grams gold per tonne. The range of gold particles was established at 900 to 1,200 microns. This certainly does not fit the Busang picture. Furthermore in Lakefield's report to Strathcona it clearly stated that after a sample has gone through the grinding circuit, alluvial gold cannot be distinguished from primary gold. Strathcona simply ignored this fact.
Fineness tests conducted on the Busang gold established the fineness at an average value of 670. This established the fact that the gold came from a primary source. Alluvial gold has a fineness range between 850 to 940 with an average range around 900 to 920.
The second myth was widely circulated by Strathcona that shavings from gold jewelry were added. I saw the photographs which depicted curly sharp shavings as when drilling into steel. These shavings were added after it had gone through the grinding circuit as this would have totally destroyed its physical characteristics. These gold shavings came from an assay drill hole into a gold doré bar (an unrefined gold bar). This was confirmed by a gold expert in Australia.
As an exploration geologist, one has to deal with many unexpected situations. One of the toughest for me was to deal with accidental deaths of my workmates: four in two separate helicopter crashes in PNG, three in a flashflood, two in a landslide and lastly the so-called “suicide” in Indonesia.
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