Grenville Gold Advancing To Production
Grenville Gold (TSX.V:GVG) is getting ready to restart production at its Silveria Mines project in Peru.
Sources close to the company have indicated that new geological data being generated by Minefill in preparation for a N.I. 43-101 report on the Pacococha demonstrate consistently high grades of gold, silver, zinc and lead from sampled locations across 42 km of mine workings.
Of 24 mapped veins on 20 levels, only 10 have been exploited since 1950, and only 1.7 million tons of ore were produced.
The neighbouring Germania and Silveria mines produced very high grade silver from 1962 to 1973, with grades as high as 24 ounces per ton passing through the mill.
Minefill Services is a specialist mining consulting company based on the 20 years of expertise of its founder, Dr David Stone, an internationally recognized expert in mine backfilling. The company is based in Seattle, Washington and employs a small staff of engineers and project managers, supported by a pool of independent professionals. The company operates from 2 principal office locations in Vancouver and Toronto, Canada.
Minefill has 2 core areas of expertise: mining rock mechanics and mine backfilling. The backfilling group spans the full range of backfill technologies from cemented rockfills, hydraulic fills, and paste fills, through to backfill geomechanics, and backfill mix designs. Most of their project work in this area is for operating mines. Minefill also provide a range of specialist services in rock mechanics, ranging from rockmass characterizations studies, through to detailed geotechnical designs for open pit slopes and underground excavations.
4 km away, Goldhawk Resources’ (TSX.V:CGK) Corichanca Mine has recently restarted and is now producing lead and zinc concentrates as well as gold.
The Corichanca mining operation is located in the mining district of Viso – Aruri in the San Mateo District, Province of Huarochiri, Department of Lima in the Central Andes of Peru. The mine has been exploited almost continuously from the colonial times. Rich silver-lead ores were exploited from the Colquipallana vein until the mid-1980s at rates in the order of 200 tpd. In addition to the conventional treatment of silver-lead-zinc ores, the advances in the technology of bioxidation of sulphides ores occurred in the early 1980s and allowed the owners to expand production to 600 tpd and treat refractory gold minerals contained in arsenopyrite.
The concentrator produces a lead concentrate, zinc concentrate, pyrite concentrate and arsenopyrite concentrate. The lead and zinc concentrates are trucked and/or railway hauled to smelters in Peru. The pyrite concentrate, recovered to keep it out of the arsenopyrite circuit, has no commercial value so it is discharged to the final tailings. The arsenopyrite concentrate has its gold and silver values within the arsenopyrite matrix. To release these precious metals the arsenopyrite is oxidized by bacteria. The precious metals are retained in the Biox circuit tailings; then this residue is leached with cyanide to extract and carbon to recover the precious metals. The loaded carbon is sent to a Peruvian refinery to recovery the gold and silver in a dore metal.
The mineralization of the Corichanca operation consists of narrow veins of the "low Sulfuration" type containing Au, Ag, Cu, Pb and Zn that filled the main fractures of the system (Constancia and Wellington veins) as well as other tension type veins such as the Rocío and Colquipallana. The veins cross the Rimac Group volcanic formation.
The mineral resources in Corichanca have been classified using the guidelines set out in the JORC Code by the consulting firm Anglo Peruana S.A. in November 2003. Their report indicates a total of 652,818 tonnes of Measured and Indicated Resources averaging 0.209 oz Au /t, 6.46 oz Ag /t, 3.18% Pb, 3.85% Zn and 0.44% Cu. These resource estimates are from the Constancia and Wellington veins. In addition, the total Inferred Resources, including all other mineralized veins, was estimated to be 3.9 million tones averaging 0.170 oz Au /t, 8.40 oz Ag /t, 2.56% Pb, 3.12% Zn and 0.35% Cu.
Other companies in commercial mineral production in Peru include Newmont Mining’s (NYSE:NEM) Yanacocha project, where Grenville Gold chairman Len De Melt was instrumental in identifying and implementing production improvement measures throughout the late 80’s.
Norsemont Mining (TSX.V:NOM) is in the process of developing the Constancia project in Peru, which holds an estimated 2.8 Billion pounds of copper, 72 million pounds of Molybdenum, and 9 million ounces of silver.
Bear Creek Mining’s (TSX.V:BCM) Corani Silver-Gold Project represents an emerging, world-class discovery of potentially bulk-mineable silver-lead mineralization. To date, Bear Creek has defined the Main Corani, Minas Corani ,Corani Este, and the Gold Zone deposits, as well as several other targets.
Peru Copper’s (TSX:PCR) Toromocho Project is situated in Morococha, an historical mining district in central Peru. The Toromocho Project is a porphyry copper, potentially open pittable, mineral deposit which Peru Copper, through its wholly owned subsidiary MPCS, has an option to acquire from Centromin.
The world’s largest publicly traded copper company, Freeport McMoran (NYSE:FCX) subsidiary Phelps Dodge’s Cerro Verde is undergoing an $850 million expansion that will permit mining a primary sulfide ore body beneath the oxide ore body currently in production. Through the expansion, approximately 1 billion tons of sulfide ore reserves averaging 0.51 percent copper will be processed through a new concentrator. Mining of the sulfide ore body is expected to begin in late 2006. The expanded copper production rate should be achieved in the first half of 2007. Current copper production at Cerro Verde is approximately 100,000 tons per year. After the expansion, copper production initially will approximate 300,000 tons per year.
