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Gold/Mining/Energy : A New Age In Gold Refining -- Ignore unavailable to you. Want to Upgrade?

To: Irv A. Weinberger who wrote (565)	1/29/1998 11:28:00 AM
From: Lee Bush	Read Replies (1) \| Respond to of 672

Irv: Are you aware of the MGAU thread? Stevens Crater in No. Ariz. Lee

To: Irv A. Weinberger who wrote (565)	1/29/1998 8:33:00 PM
From: Michael J. Wendell	Read Replies (1) \| Respond to of 672

Hello Irv Welcome to the thread. You are asking good questions. Your first question is about cindercones. They are basaltic little erruptions that erosion has removed much of the surface flow, leaving a hard core that erodes slowly and usually sticks out of the ground. Conventional gold deposits form with heated solutions that come up the volcanic channel ways and fractured local rocks. These waters carry metals from the magma below. As the pressure and temperatures drop during the acsent, deposits form. The cindercones are different. These were gassey little guys. The gasses were very hot and they carried the metals upward. The gold is deposited in the country rock surrounding the cone and in the vessicular porosity that formed during the rocks cooling. The gold is on the surfaces. It is formed by condensation and collection onto minerals like zircon. They are microcluster types and are certainly DDs meaning darned difficult. I don't like to suggest specialist assayers in this area of the analytical field, but let me give you some suggestions. One is, do not use instrumental assays. These are assays that let the machine do the reporting. Too risky for a novice to make judgement calls on a procedure that has risks of creating bogus values. Do not rely on an assayer with lots of credentials hanging on the wall. Thet person may be great, but then again he might be only the salesman with a bozo doing the actual work at minimum wage in the back room. You can trust an an instrumental analysis if it is only being used to confirm the results produced by fire or other extractive assay. The interferences are removed once the lead button has been refined to dore'. Folks that use refinery assay methods, that is they digest the rock, precipitate the values and go through extensive refining methods are usually ok. The procedures here require an extensive knowledge of precious metals chemistry and the refinery practices. Problem here is expense. I know of one European refiner that does an excellent job, but the price is probably over $2000 per assay US. There are good inbetweeners, but be careful. Take some of the sample and have it ground to 200 mesh Tyler. Now weigh out about 5 ounces of material as a head sample. Pan the rest of the sample. Dry and weigh the concentrates. Package them separate. Now dry the tails and mix the material up real well. The assay of the head should equal the weighted balance of the recovery added to the weighted recovery of the tails. There is a formula for this if you need it. Most assayers fail the test with DDs, but it is good to know how bad they are. I will give you the formula if you request it by email. You are right about the final judgement for a recovery is by the test of selling it. But who will pay for the little bit you have and why risk a fortune to go into processing when you do not know if the deposit is for real. Get some of the metal and send it to Ledoux in Teaneck, NJ. They do umpire assays for the refiners and bankers, that ought to be good enough for you. They will verify processes and assay procedures you have also, but you may be a little premature here. You might also call Stan Wardle. I will give you his number by email. He uses refining methods. Tell him you want the metal collected so you can get it verified at Ledoux.He is not inthe assay business, but he may do the work if I ask him to do it. He like me, I think. I have no idea what he will charge, but it will not be as inexpensie as a regular assay. Caution here can keep you out of misery later on. mike