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Gold/Mining/Energy : Medinah Mining Inc. (MDHM) -- Ignore unavailable to you. Want to Upgrade?

To: Mike Gold who wrote (4839)	8/4/1998 10:46:00 AM
From: Mike Gold	Read Replies (3) \| Respond to of 25548

Here is a more detailed description of NPEC's extraction system written some months ago by Juanita after she viewed the video tape of the process: To all: Well, I have watched the tape. The area around the site looks like a mining site....not really pretty...but not ugly either...just barren in spots...with some palm trees in the area. I don't know if it was a windy day or if the area is always pretty windy, but it was windy the day they shot the tape. I saw a bicyclist off in the distance and I heard some dogs barking, so it looked like they weren't way off in the wilderness. The narrator was very laid-back and matter of fact. And now for the information from the tape: The site is the Urbano Project, located in the Pocone-Mato Grosso area of Brazil. The plant is one of column flotation units that are reprocessing the ball mill reject that has been produced in the Pocone region. Gold has been produced for 200 years in various stages and methods of production in that area. For a long time, hammer mills were used and large amounts of rejects were piled up. About 10 years ago, ball mills were introduced and the hammermill rejects that had around 1 gm of gold or perhaps a little bit more were reprocessed through the ball mills. The technology did not exist to use a flotation type system to extract the fine gold from the ball mill material. What the workers did was to put the ball mills through a gravo-metric circuit and this circuit could not extract the fine gold from the ball mill material. The fine gold simply passed through the system with the rejects and was pumped into the huge reject areas. What NPEC has done is to install a column flotation system that will process and is processing 1,000 tons of this ball mill material per day and extracting the gold from that ball mill material. There is a silo which is loaded with approximately 30-40 tons per hour of this material. They don't have to mill it at all. They simply put it into the system and a machine loads it into the 35 ton silo and at the bottom of the silo is a system that loads the material into the plant. The material is then rotated and fed into the conditioning unit where the pulp is made. It's about a 50-60% solid when it enters the conditioning unit and water is added to bring it down to about 35-40%. Flotation chemicals are then fed into the system. It is then fed by gravity into a tank at the bottom, and there is a very simple screen system just to screen out the trash and any pebbles that might get through. At the bottom of the tank is a homogenous pulp that is 35% solids and in the lower tank the chemical is added that makes the foam that the gold actually floats up on in the flotation column. There are 3" diameter pulp pumps that are rubber lined and these last a lot longer than the old metal pumps. These pumps pump a specific amount of pulp into the columns per minute. It's something like 300 liters per minute that is pumped in at the present time. From there the material passes into the columns and the gold is floated off. From the pulp tanks, the material is pumped into the columns where it passes through an injector system where air is injected into the pulp that has the flotation chemicals in it and the gold is floated off into the column. NPEC has a double column flotation system. The initial rubber column takes out the majority of the gold and the scavenger column takes out any gold that is missed by the first column. When the gold is floated off with the bubbles, the bubbles are washed off with the water and the concentrate with the gold in it goes into the concentration tanks. There is about a 100 to 1 ratio, so for every 1,000 tons that are put through the plant, there are about 10 tons of concentrate. The concentrate carries around 70-80 grams of gold per ton. The concentrate is then pumped from the small pulp pumps to the leach tanks. The leach system is a 127,000 liter leach system that NPEC purchased and installed. At the present time there are four tanks installed which is about 100,000 liters. The system is large enough to handle five plants. The concentrates are pumped into the leach tanks and when the tanks have a sufficient amount of concentrate in them, cyanide and a soda is then mixed in and the gold is leached for about 24 hours. The gold is very fine, and they find that in about 24 hours they can leach out about 10 tons of concentrate. The plant operates on fairly low horsepower engines with a couple of 15 hp motors. The plant operates pretty much by itself. The workers really don't have much to do except watch the system and make sure that there are no problems or overflows. The old cyanide is drawn off and the pulp is washed with a new cyanide solution to insure that all the gold is taken out. There is a fairly large fresh water lake nearby. The whole system is a closed system. Water is pumped from the lake, used at the plant, and then brought back clean into the lake. About 300 liters per minute are pumped into the reject area. The gold still in there contains about .04-.05 gms per ton. New dams are being built around the entire area - about three hectares in size and they will eventually encircle the entire reject area. There is a six bedroom house with an office and a laboratory and a large workshop area. Almost everything mechanical that needs to be done can be done at the site. There are two extra 27,000 liter tanks which haven't been installed yet, but these can easily be installed in the leach system so that they can in fact process from 5,000 tons of material per day. The gold material is heated to about 1200 degrees Centigrade and then poured into 1/2 kg bars of gold. This is about a one day's production at the present time. When everything is installed, NPEC is looking to produce five times that amount per day, or five 1/2 kg bars of gold per day for the next five to six years. Well, that's it for now. I'll try to answer questions or put more on later. Right now...it's tax season....most of the rest of my day is filled up. Later, Juanita