Engineering & Mining Journal

SEP 2012

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NEW AFTON chamber and the CTC 4-5, a conveyor transfer center." for a long period of time, the mine pro- vides extra support for the drawpoints. A concrete floor is poured and steel sets are placed at the brow for extra support. "We will pull hundreds of thousands of tons from one drawpoint, which equates to millions of dollars in revenue from that location, so we really reinforce those areas," said Strom. New Afton uses an overdrawn venti- lation system that sweeps over the pro- duction areas to exhaust raises, which pulls air down to the ventilation level and then out through dedicated exhaust raises to the surface through the fans. "We have a push-pull system that over- draws the production area once," Strom said. "That dust goes directly to exhaust. All of the fans are set to intake now. When the last of the vent raises are completed, we will pick up those fans and turn them around." The final configuration will have three intakes and three exhaust fans. The mine has also constructed an impressive refuge chamber as far as design and use. It is located at the foot- wall strike drive near the maintenance shop on the extraction level where much of the activity will be taking place. The chamber is used regularly. It has an office and a large screen LCD television above a lunch room with microwaves. "In the event of an emer- gency, we would move to the secondary support systems," Strom said. "If for some reason mine air fails, we have a MineARC CO2 scrubber and oxygen bot- tles. The back-up power system will support 60 people for 36 hours. If the system has to be used longer than 36 54 E&MJ; • SEPTEMBER 2012 hours, a tertiary plan makes use of a 600-m drill hole connected to the sur- face for a water line, compressed air and communication." Of the 1 million tons on the ground, nearly 60% was conveyed to the surface by belt. The conveyor network consists of five flights of 42-in. steel cord belting (ST 3400) with twin 600-hp motors powering head-pulley drives. The third flight is the longest conveyor, traversing 1.2 km up a 16.6% grade to surface. The belt has been engineered so the bot- tom belt turns over to prevent spillage. Industrial Equipment Manufacturing (IEM), a Vancouver-based firm, designed all of the transfer stations. Prior to the conveyor installation, ore was trucked to the surface. "The conveyor system has made a huge dif- ference," Tolden said. "As far as drift- ing, in April the entire operation had a record month of 955 m. We just recent- ly completed the gyratory crusher The mine also recently completed a 600-m slickline, moving the trans-mixer traffic off the ramp, which transported the concrete from the surface. It deliv- ers concrete closer to the areas where it is most needed. "We are transporting great amounts of concrete and fiber- crete for development purposes, road- ways and drawpoints," Strom said. "The slickline now dumps concrete directly into the Normet trans-mixer trucks." New Afton has a total of 112 pieces of mobile equipment. Some of it is used on the surface, but most it works in production or development or sup- porting those activities. They have 12 LHDs. The 10-yd3 Atlas Copco LHDs are used on production and 7-yd3 Cat scoops are used for development. "In terms of meters, for the year, we are performing quite well," Tolden said. "We have been transitioning from con- tractor support to in-house develop- ment. New Afton is mining at a rate of 500 m/month and Thyssen Canada is at 250 m/month. We had Cementation Mining on site, but they have now been phased out." The milling capacity will briefly over- take mine production this year until the mine reaches full production. "There is a period of draw down until the mine reaches 11,000 mt/d in the first quar- ter of 2013," Tolden said. The stock pile provides a cushion until the mine gets up to full capacity. Mining in the Modern Era "We blasted our first undercut June 29, 2011, for the starter raise," said Kurt Keskimaki, mine manager for New Milling capacity will briefly overtake production this year until the mine reaches full production. www.e-mj.com

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