Engineering & Mining Journal

SEP 2017

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REGIONAL NEWS - LATIN AMERICA 16 E&MJ • SEPTEMBER 2017 www.e-mj.com East Francine Vein, including 0.72 ounc- es (oz) per ton (t) of gold and 288 oz/t of silver over 4.6 feet. "San Sebastian has been a ma- jor component of Hecla's success over the past year and a half, and we see this continuing into the future," said Phillips S. Baker Jr., president and CEO. "We started production with a two- year mine life, expecting exploration success to extend it further. It has, and today, we see a combination of reserves, resources and exploration discoveries en- abling production through 2020. All of this has been done with a minimal capital investment by using a contract miner and leasing a mill. San Sebastian has allowed Hecla to deliver production growth, cash flow and triple-digit-plus returns." Brazil Revises Policy on Renca The Brazilian government will publish a new decree regulating the dissolution of the National Reserve of Copper and Asso- ciate Minerals (known by its Portuguese acronym Renca) to clarify country's com- mitment to protecting the environment. It will regulate mineral exploration in ar- eas with no protected areas, indigenous lands or border strips, and was published in an extra edition of Brazil's Federal Official Gazette (the Diário Oficial da União, or DOU). Brazilian President Michel Temer cre- ate a firestorm when he dissolved Renca, which opened 47,000 km 2 in the Amazon for mining activities. He and his admin- istration suffered an immediate backlash from uninformed environmental activists, who immediately associated the move with deforestation in the Amazon. According to Brazil's environment minister, Sarney Filho, the revision will make the rules clearer, especially since the previous text caused so much confu- sion. "The new text firmly reiterates the position that there can be no mining in protected areas," he explained. Located between the states of Pará and Amapá, Renca is well endowed with precious metals. Artisanal miners, known as garimpos, are currently mining gold il- legally from the region and polluting the local waterways with mercury. By opening the reserve to professional, private min - ers, the government hopes to clean up the mess and stop the garimpos from plun- dering Brazil's wealth. Mine Life is Extended to 2028 at Iamgold's Rosebel Gold Mine Iamgold has reported an updated reserve estimate for its Rosebel gold mine in Su- riname that will extend mine life to at least 2028. Attributable proven and prob- able reserves have increased 80% since the end of 2016 to 3.5 million ounces (oz), as of June 30. Over the same period, Rosebel's mea- sured and indicated resources, inclusive of reserves, increased by 55% to 8.9 million oz, and its inferred resources in- creased by 322% to 2.5 million oz. Aver- age reserve grade remains unchanged at 1 gram per metric ton of gold, but now includes dilution. The updated reserve and resource es- timates for Rosebel do not include any mineralization from Iamgold's Saramac- ca project 25 kilometers (km) southwest of the Rosebel mill. The anticipated positive impact of the Saramacca de- posit will be better known when Iamgold completes an initial resource estimate for the project, currently expected before the end of September. Rosebel is owned 95% by Iamgold and 5% by the government of Suriname and is located in northeast Suriname, about 85 km south of the nation's capital city, Paramaribo. Mining to date has been carried out in eight open pits. Production attributable to Iamgold during 2017 is forecast to be in the range of 295,000 oz to 305,000 oz. The new Rosebel resource models incorporate some new ore from the sad- dle zones between the pits; however, the amount from these zones is limited. Ex- ploration of the saddle zones is ongoing, and additional data obtained from the drilling program will be incorporated into future reserve and resource estimates. Significant factors contributing to Rosebel's new reserve estimate includ- ed new resource models for all of the Rosebel orebodies, which incorporated information from both diamond and re- verse circulation drill-hole data, extensive geologic mapping completed in recent years, and a comprehensive geostatistical review by internal and external experts. A positive impact also resulted from changes in the Rosebel cost model, based on major cost improvements over the past couple of years due to significantly improved mine and mill productivity, re- duced fuel prices, a favorable change in the local currency exchange rate, signifi- cantly reduced general and administra- tive costs, and higher mill throughput for hard ore as a result of improvements and investments in the crushing and grinding circuit in the mill. A revised mine planning approach also contributed to reserve and resource growth. The new approach includes a detailed pit phasing scheme com- plemented by an optimized mine- sequencing algorithm to maximize the net present value of the mine sched- ule, including the use of variable cutoff grades over time. Iamgold President and CEO Steve Letwin said, "Rosebel continues to transform, enhancing the value of this operation. With the 80% increase in reserves at the Rosebel concession and a resource estimate for Saramacca to follow, a new lower-cost, longer-life mine is taking shape . . . Most impres- sive is that the vast majority of the incre- mental 1.6 million oz added to reserves is due to mine planning optimization, which has allowed us to economically access more ounces." Trek Planning Restart of Aurizona Gold Mine Trek Mining has awarded the Engineering, Procurement, Construction and Manage- ment (EPCM) contract for redevelopment of its currently shuttered Aurizona mine in northeast Brazil to Ausenco Engineer- ing Canada. Based on a recently com- pleted feasibility study, the refurbished and upgraded Aurizona plant is planned to produce an average of 136,000 ounc- es per year (oz/y) of gold over a 6.5-year mine life, with year-end 2018 targeted for the first gold pour. Redevelopment at Aurizona is based on proven and probable mineral reserves of 19.8 million metric tons (mt) grad- ing 1.52 g/mt of gold for 971,000 oz of contained gold. Life-of-mine all-in sus- taining costs are estimated at $754/oz. Initial capital to fund construction and commissioning is estimated at a modest $130.8 million as a result of Trek's ability to leverage significant existing infrastruc- ture. Capital costs also reflect the use of contractor mining, eliminating the need to purchase a new mining fleet. Open-pit mining will begin with min- -

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