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Gold/Mining/Energy : Precious and Base Metal Investing -- Ignore unavailable to you. Want to Upgrade?

To: zebra4o1 who wrote (34185)	2/4/2005 3:24:37 PM
From: E. Charters	Read Replies (1) \| Respond to of 39344

It is hard to say, On one hand with the break down of the mountain, there is massive dilution, on the other hand there is concentration of the heavies into channels as the lights are washed away. In a good placer the rock breaks down fast into smallish grains that are easily washed away, so the placer concentrates well. All that is left is small grains of the sediments and vein and granitic cobble. Usually in BC I rarely saw placer gold in granitic stream gravels as the gold was not there to start and too much remained behind. 2 mountains of 3,000 feet in height would be 4.7 billion tons of material. Removed would be half that. Vein material could be 1% of that. So dilution would be 100 to one. Reconcentration could be up to 8 to one, so effective grade of the stream could be 12 time less than original grade. The Ross Placer was formed from many qtz veins running about 0.15 OPT or in those days about $2.40 per ton grade. The Ross Placer itself ran about 25 cents per yard to 50 cents per yard. About 16.5 cents per ton worst case. A factor of 14.5 to one to seven to one, which corresponds to my assertion of 8 to one very well. 4 to one is just being conservative. The Yukon Placers may have had a much greater concentration factor because of the softness of the rock they eventually got caught in and the coarseness of the gold. If one takes the average dug grade of the large scale Yukon dredging ops, we get 5 dollars per ton. Taking a factor of 8 we get 40 dollar veins, or 14.5 we get 87 dollar veins which is 0.16 OPT. But this is very conjectural. EC<:-}