Marudi gold mine will be environment friendly
-says manager
Stabroek News
April 13, 2004
The Marudi Mountain Gold Mine will not be using cyanide for its operations, but instead a more environmentally friendly method in keeping with safer mining practices.
Resident Manager of Vannessa Ventures Limited, James Stonehouse said on Wednesday that the flotation method of extraction that the company plans to use would actually help the environment.
The gold mine is a subsidiary of Vannessa Ventures Limited and plans to have a yield of 40,000 ounces of gold - US$1.5M worth - per year. The cost to establish the mine is around US$5M to US$7M and is expected to last seven years. Small amounts of silver would also be produced.
The draft Environmental Impact Assessment (EIA) for the proposed mining operation also makes the point that no cyanide would be used.
The mine is to be located in the eastern portion of the Marudi Mountain, some 40 miles from Lethem in Region Nine.
Stonehouse said that it would be a simple open pit operation and the extraction would be done by a rock grinding and frothing exercise. He added that the froth method would entail using froth to float the valuable mineral to the surface.
The draft EIA said that in addition to the non-use of cyanide, no other poisonous substance would be used in the mining or gold extracting process. Stonehouse told Stabroek News that the mine would be using constituents resembling oils and detergents for the extraction and processing of the gold.
He added that with the use of such a method, all of the harmful metals in the rock would be removed.
The draft EIA said that test work has indicated that a concentrate containing approximately 90% of the contained gold can be produced by froth flotation.
It added that a crusher would be added to the circuit to convert the mill, used to process soft rock ore during phase one, to handle the harder phase two ore. The crusher will reduce the size of the material arriving at the stockpile from the mine. Hard rock and suitable material stockpiled from the gravity process will be crushed and fed to a SGA or ball mill to reduce the material to a relatively coarse grind. The study said that the ground material would contain approximately 40% of material finer than the ASTM No. 200 sieve, after which the material would be passed through the original gravity circuit.
According to the draft EIA, after gravity concentration of the ground ore, the residual material passes to the flotation circuit. In the flotation circuit, ground ore comes into contact with pine oil and air bubbles in an agitated tank.
The gold adheres to the pine oil that coats the bubbles, which then rise to the surface of the tank bringing the gold with them. The particles of gold are scraped off the surface as foam, and the foam is collected and smelted as gold.
The flotation process consists of producing a mineral concentrate through the use of chemical conditioning agents followed by intense agitation and "air sparging" of the agitated ore to produce a mineral rich foam concentrate. Specific chemicals are added to either float specific minerals or to suppress the flotation of other minerals. The draft EIA says the flotation concentrates would be sent to an off-site smelting facility for the recovery of gold and base metals.
The study said too that cyanide is preferred to other methods because of the economy of its implementation. "Where amalgamation plants could recover about 60% of the gold present, cyanide could recover about 90%," the draft EIA said. It said too that cyanide is as close to a universal solvent for gold as has been developed. But it named alternative lixiviants or agents including bromides (acid and alkaline), chlorides, thiourrea and thiosulfate.
Stonehouse said that the company has six to eight more months of exploration work to do before extraction can begin. He said the work depends on the various permits that the company is yet to get. The mining permit is dependent on the environmental permit - which is dependent on the findings of the final EIA - which the company is to submit to the Environmental Assessment Board within a week.
Stonehouse told Stabroek News that he hopes to have all the permits by the end of this month. He said that the company had all the requisite meetings in the nearby communities to the proposed mine site, some of which are Aishalton, Krowdar & Lumedpaw, Achuwib, Maru-nawa, Waruwaunawa, Shea and Kuiwini.
According to Stonehouse, the communities will get a lot of benefits from the mine, which would have a 97-person workforce that is 95% Guyanese. He said that persons from the areas would be given preference.
He added that transportation would also be improved in the communities and that this would make for better access to education and health care. He also made the point that persons in the areas near to the mine site would have better access to markets for their produce because of the roads. He said that the people in the community were very supportive of the project.
He said that the company has some of the equipment already in the country and it is being used by Vanarde Mining Inc, also a Vannessa subsidiary. This company does gold and diamond mining in the Potaro River. Stonehouse said that more equipment would be procured after the company begins operation.
Stonehouse told this newspaper that there were some hiccups with the logistics since the operation was new to the area. But he said that no one is to blame for this and the project was only slightly behind schedule.
He commended the government for being open, helpful and encouraging investment.