Sherwood Copper Corp. said Dec. 12 that a pre-feasibility study shows the Area 2 deposit at its Minto copper-gold mine in central Yukon has a reserve that supports a 45 percent increase in mill throughput and a 43 percent increase in total project copper and gold production and an immediate increase in copper and gold output. The study called for an increase in mill processing to 3,500 metric tons per day from 2,400 tpd and higher metal production starting next year due to processing higher-grade ore.
Sherwood has updated its mine plan as a result of the increased production that began late in 2007. The accelerated plan estimates the mining of Main pit to be completed in 2010.
Once Main pit is complete the company will start on Area 2. Stripping of Area 2 will not start until mining of Main pit is complete so that the waste material can be put directly into Main pit. Stockpiled ore will be processed during this time.
At 3,500 metric tons per day the company has enough ore in Main pit and Area 2 to stay in production for an estimated nine years ending in 2015.
New discoveries augment Area 2 reserve estimatesThese new findings are the result of 18,134 meters (59,495 feet) of diamond drilling completed in Area 2 in 2006. A resource estimate has been completed by Lions Gate Geological Consulting Inc. and SRK Consulting (Canada) Ltd.
The measured reserves at Area 2 are 432 million pounds copper, 231,000 ounces gold, and 2.462 million ounces silver, the company said. Adding the indicated reserves brings the total resource estimate up to 567 millions pounds copper, 297,600 ounces gold, and 3.185 million pounds silver.
In 2007 Sherwood did 23,618 meters (77,487 feet) of drilling at Minto. With significant new copper-gold discoveries at Gap, Copper Keel South and Airstrip SW the company said the results of the 2007 drill program could further increase production and/or mine life. Assay results are still pending on 34 of the 102 holes drilled.
Phase 2 mill expansion completedSherwood completed Phase 2 mill expansion at Minto on Dec. 15, increasing production from 1,563 metric tons per day to 2,400 tpd.
Sherwood President and CEO, Stephen Quin said the expansion will increase production at Minto to 50 million pounds of copper per year.
Commissioning of Phase 2 will continue until January. The focus of the commissioning will be to ensure that the filtration of tailings and copper concentrates can keep up with the increased production. The crushing, grinding and flotation capacity of the mill has been expanded to accommodate a 3,500 tpd Phase 3 expansion recommended in a pre-feasibility study.
Brad Kopp, Sherwood’s corporate development manager, told Mining News that much work on the Phase 3 expansion has already been completed and the company anticipates finishing it in early 2009.
Grid power in 2008Yukon Energy, meanwhile, has received all the permits and certificates needed to proceed with surveying, clearing and construction of Phase 1 of the Carmacks-to-Stewart transmission line. The access and land use permits were issued by the Selkirk and Little Salmon Carmacks First Nation in December.
Crews have begun survey and clearing brush for the new transmission line and construction is scheduled to start in March. Lines are expected to be connected to the Minto Mine by the end of 2008. Sherwood said connecting to grid power will significantly reduce operating costs at the mine.