Engineering & Mining Journal

AUG 2018

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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72 E&MJ • AUGUST 2018 target new areas, including Zone 3 and Chaucha, as well as an extension of Central, South and West Ayawilca. Graham Carman, president and CEO at Tinka Resources, said: "This drilling campaign will aim to add more high-grade resources to our portfolio and fur- ther improve the economics of the project. We will have a resource upgrade by June or July. In parallel, a detailed metallurgical study will occur in Q2 2018 and then we will complete our preliminary economic assess- ment (PEA) over the second half of the year." Ayawilca also hosts a tin resource, which increased in the latest 43-101 report of No- vember 2017 to a total of 10.5 million mt containing 145 million lb tin. "The tin lies deeper than the zinc so it will probably not be mined from the start, yet we would like to include the tin in our upcoming PEA as its realization is very high in terms of value. We will need to do more metallurgy and see what we can incorporate this year," Carman said. Another junior involved in zinc exploration and development is Zinc One, whose primary focus is to reactivate zinc production at the Bongará mine, following the company's ac- quisition of Forrester Metals in 2017. The company has been drilling in the area to bring the historical resource from previous mining operators to 43-101 standard. The mine was exploited most recently by Cemen- tos Pacasmayo, and the company's plan is to be back in production by 2020. Bongará's zinc mineralization is high grade and heavily oxidized, hence Zinc One's strategy to set up a Waelz kiln on-site run- ning on anthracite coal. Bill Williams, COO of Zinc One, gave more details: "The Waelz kiln provides an efficient process with low capital costs, and eliminates waste manage- ment expenditure. Thanks to the pyrometal- lurgical process, there are none of the typical tailings that mines have to deal with. The waste will be a slag, which is chemically in- ert and can be recycled and used for road aggregate." Precious metals There are no large junior-held projects in the pipeline, and most of the exploration activ- ity is related to early stage projects or small mining operations by juniors that decided to move into production. One such is PPX Mining, that has an ex- tensive bulk sampling program ongoing from the Callanquitas structure at the Igor project in La Libertad. Over the last year, the com- pany has mined 25,000 mt of bulk sample, which has been processed at a nearby toll milling facility. "This has given us reams of hugely valuable data, such as information on recovery, grade distribution, and ore control underground. In addition, we have received geotechnical and engineering information from the working faces at the mine – what stope designs and orientations to use, which size ramps work the best, and at what cost", declared Brian Maher, president and CEO of PPX Mining. Maher said that so far, bulk samples have averaged a grade close to 8.5 g/mt, and that that all the data gathered will help the com- pany make an informed decision to go into production, via the pre-feasibility process (PFS). The PFS will evaluate the economics of a 350 mt/d underground mine, using a heap leaching process to recover gold and silver. The company expects to receive its permit to build the facility in Q4 2018. Beyond Callanquitas, other areas of inter- est in the Igor project are the Portachuelos discovery and Tesoros. According to Maher, the company has identified five parallel brec- cia zones at Portachuelos, with grades near the surface of up to 2.7 g/mt gold equivalent. "While this is 'lower grade,' from a bulk and surface mining standpoint, it is actually quite spectacular," he assured. Following a similar model, Lupaka Gold has been focusing its efforts on Invicta, a gold-copper polymetallic underground proj- ect. The company's plan is to start mine development, use a contract miner and then Graham Carman, president and CEO, Tinka Resources. Brian Maher, president and CEO, PPX Mining.

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