Engineering & Mining Journal

SEP 2017

Engineering and Mining Journal - Whether the market is copper, gold, nickel, iron ore, lead/zinc, PGM, diamonds or other commodities, E&MJ takes the lead in projecting trends, following development and reporting on the most efficient operating pr

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REGIONAL NEWS - U.S. & CANADA 10 E&MJ • SEPTEMBER 2017 The Arrow mineralization occurs in stacked high-grade veins that demon- strate strong continuity on strike, dip and vertical extent. Additionally, there are nat- ural pillars due to the spacing between the mineralized A1 through A4 shears. Due to the geometry of the Arrow deposit, approx- imately 93% of the mineral resource has been converted into mineable resources. The positive results of the Arrow PEA are further supported by a high process recov- ery rate of 96% due to simple mineralogy and low deleterious elements. Processing is based on a conventional flowsheet that in- cludes crushing and grinding, acid leaching, liquid-solid separation via counter current decantation, solvent extraction, yellowcake precipitation, and a paste tailings plant. Cemented paste fill tailings would be used to backfill stopes, with the excess placed in a purpose-built underground tailings storage facility. Among other ben- efits, this tailings management process is expected to significantly reduce the sur- face footprint of the project. The Arrow PEA was completed by Ros- coe Postle Associates and is based on an indicated mineral resource of 179.5 mil- lion lb of U 3 O 8 contained in 1.18 million mt grading 6.88% U 3 O 8 and an inferred mineral resource of 122.1 million lb of U 3 O 8 contained in 4.25 million mt grad- ing 1.3% U 3 O 8 . The PEA does not include the results of the NexGen's winter or sum- mer 2017 drill programs, which will total over 66,000 m of additional drilling. Cliffs Natural Resources Has New Name Cliffs Natural Resources Inc. announced it has renamed the company to its historical name Cleveland-Cliffs Inc. The company has been an important part of the North American iron and steel industry for many decades. The name change is part of the celebration of the 170 th anniversary of the company. It is effective immediately. "The historical name Cleveland-Cliffs is synonymous with our strong heritage, and is the perfect one for our next era of growth," said Lourenco Goncalves, chair- man, president and CEO. "As we did more than 60 years ago, when we adopted pel- letizing as a smart business opportunity to utilize American iron ore and provide the domestic blast furnaces with customized pellets, Cleveland-Cliffs is once again rein- venting itself as the supplier of high-quali- ty iron units to the Great Lakes region. "With our expansion into the pro- duction of Hot-Briquetted Iron (HBI) to supply the growing electric arc furnace steel industry, Cleveland-Cliffs is the best name to represent our strong present and our bright future." McEwen Mining to Acquire Black Fox From Primero McEwen Mining has reached an agreement with Primero Mining Corp. to purchase its Black Fox Complex near Timmins, Canada. The agreed purchase price is $35 million, subject to closing adjustments. Definitive documentation is expected to be complet- ed before the end of this month. "Buying the Black Fox Complex pro- vides fantastic synergies with our recent- ly acquired Timmins deposits," said Rob McEwen, chairman, McEwen Mining. "Our objective is to build a long-term production platform with a robust pipe- line of production, development and ex- ploration assets, all feeding into a single processing facility. He added that the acquisition would immediately add to its gold production. "Black Fox comes with a talented op- erating team, an underground mine pro- ducing 50,000 ounces to 60,000 ounces of gold in 2017, a processing facility with excess capacity, two future development opportunities, and excellent exploration potential," McEwen said. McEwen Mining's principal assets con- sist of the San José mine in Santa Cruz, Argentina (49% interest), the El Gallo Gold mine and El Gallo Silver project in Mexico, the Gold Bar project in Nevada, the Timmins projects in Canada, and the Los Azules copper project in Argentina. MSHA Expected to Delay, Amend Workplace Exam Rule The Mine Safety and Health Administra- tion (MSHA) will likely propose changes to its embattled Workplace Examination Rule, Husch Blackwell reported. The rule, a holdover from the former President Barack Obama administration, requires extensive changes to the way mine oper- ators must perform, record, communicate and respond to workplace examinations performed on every shift. MSHA adopted the rule on January 23. After facing significant criticism around the country and a rulemaking challenge, the rule's effective date was delayed until October. Based on the new information, the law firm said it expects that MSHA will issue a further extension soon. McClean Lake Mill is Granted 10-year License Renewal AREVA Resources Canada and Denison Mines have been granted a 10-year license renewal for the McClean Lake uranium mill- ing operation, valid as of July 1, 2017, and extending to June 30, 2027. The McClean Lake mill is located approximately 800 ki- lometers (km) northeast of Saskatoon, Sas- katchewan, and is owned 70% by AREVA, 22.5% by Denison Mines, and 7.5% by OURD Canada. AREVA is the operator. The McClean Lake mill is one of the most technologically advanced uranium mills in the world and the only facility in the world specifically designed to process high-grade uranium ore without dilution. The mill currently processes ore from the underground Cigar Lake mine under a toll milling agreement. Cigar Lake is located 70 km southwest of McClean Lake and is currently the mill's sole source of feed. Cigar Lake is the world's highest-grade uranium mine, with an average grade of 15.9% U 3 O 8 . Mine ownership is 50.025% Cameco Corp., 37.1% AREVA, 7.875% Idemitsu Uranium Exploration Canada, and 5% TEPCO Resources. Cameco is the operator. Cigar Lake is mined by an innovative jet-boring mining method operated from tunnels in the basement rock below the orebody, using high-pressure water jets to mine out cavities in the ore. A mixture of ore and water is piped away from the cavities to underground processing circuits, where it is ground and thickened and pumped to the surface for transportation to the McClean Lake mill. Production is forecast to reach design capacity of 18 million pounds per year (lb/y) of uranium concentrate by 2018. The McClean Lake mill has a total pro- duction capacity of 24 million lb/y of ura- nium ore concentrate, providing it with ex- cess capacity to process potential new ore from McClean Lake and other uranium de- posits in the future. Denison's preliminary economic assessment for its Wheeler River project, completed in 2016, contemplates the use of the McClean Lake mill on a toll milling basis to process mine production from Wheeler River's Gryphon and Phoe- nix uranium deposits. The Wheeler River project is a joint venture between Denison (60%), Cameco Corp. (30%), and JCU (Canada) Exploration (10%).

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