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Gold/Mining/Energy : Gold Price Monitor -- Ignore unavailable to you. Want to Upgrade?

To: long-gone who wrote (85442)	5/16/2002 6:17:05 PM
From: goldsheet	Read Replies (2) \| Respond to of 116820

World Gold Demand Reacts To Price Volatility "Global consumer demand for gold in the first quarter was 10% lower at 749.5 tonnes than that posted a year earlier according to the World Gold Council's quarterly survey Gold Demand Trends, published today" Nothing like a price rise to reduce demand ;) FULL STORY: biz.yahoo.com

To: long-gone who wrote (85442)	5/17/2002 11:12:55 AM
From: E. Charters	Respond to of 116820

I don't know about what you posted, but I have an idea that gold could be profitably extracted using super-gravity from tailings ponds. There is a chance that we could use a machine from the food industry for the process made by Hobart :) People used to tell me about placer miners using Krebs cyclones (A cone tube that slurry is spun into to separate streams) -- to concentrate gold. The cyclone can generate a high G field of up to 200 to one. In this regime the differential of gold to quartz increases although the ration stays the same. So 200 X 19.5 (gold SG) = 3850 and 200 X 2.5 (qtz) = 500. The difference is 17 at one G -- and 3350 at 200 Gs in spin cycle. Technically the relative difference in weight of AU has increased in the centrifugal field (although again, not by ratio). This makes separation in a hindered settling environment (slurry) more sure. Knelson and Falcon are two companies in Vancouver that have taken advantage of that in recent times. The patents go back to 1934. The trouble with the process of increasing gravity in a pumped cyclone or a spinning basket is that you get compaction and this prevents further settling. This can be solved by fluidizing by pressure as Knelson does or perhaps by other means. It is also written in texts that the efficiency of separation increases as the SG of the supporting fluid increases. So a high SG fluid makes for a sharper demarcation line of concentration and a better recovery of heavy products. This last point is not always suspected. Only one product I know of, made for lab work, takes advantage of using heavier media with good results. The problem is how to retain the media in continuous throughput devices. I think I know of a way to combine this with a cheap to produce static structure for effecting a concentrate of high recovery ratio. Once a concentrate of the heavy product is made, there are some ways to further reduce it to extract the metal that is not widely done but would be cheap and a better extraction method than many previous ones. I think these processes are cheap enough to make money where many tailings processes in the past have not achieved good results. The chiefest problems with these processes is that they used complex chemical processes that had environmental and oxidation-recovery issues, and energy intensive grinding that is also high capital cost. A practical gravity/concentrate recovery program could lower costs by 75% or more. A lot of people are afraid of the recovery of gravity processes as they usually average 50% or less in a one G field with gold. I think that could be improved by 50% at least with better methods. As well, the real formula to look at is dollars in versus dollars out. You lower the first and raise the second until it equals profit and multiply volume until a satisfactory return is made. In placer fields a good enough grade was considered to be 1/80th of an ounce per ton. Today that would be less than 4 dollars per ton. Can you pump fine slurry, spin it, and treat the concentrate for less than 4 dollars/ton? You can pump 400 GPM with a 20 HP pump at 25% density. That is 27 tons of dry feed per hour. At 20 cents per KW that is 15 X 20 = $3.00 divided by 27 or 11 cents per ton. All other costs cannot exceed $1.50/Ton at scale. Looks like with some work it might work. EC<:-}