Engineering & Mining Journal

JUL 2018

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REGIONAL NEWS - AFRICA 18 E&MJ • JULY 2018 Nevsun Extends Mine Life at Bisha Nevsun Resources and its Eritrean part- ner ENAMCO have approved an expansion of mine production and an extension of mine life at their Bisha open-pit zinc-cop- per mine in Eritrea. The new mine plan is based on additional feed of 3.3 million metric tons (mt) of high-grade ore to the Bi- sha mill and will extend operations through the end of 2022. Additional payable pro- duction of 470 million pounds (lb) of zinc and 52 million lb of copper in concentrates will be achieved over that time frame. Bisha production in 2018 is forecast to be in the range of 210 million to 240 million lb of zinc in zinc concentrate and 20 million to 30 million lb of copper in copper concentrate. In addition to increased production and revenue, the extension of Bisha mine life provides time for Nevsun to advance assessment of the Asheli and Harena underground deposits near Bisha and to consider further open-pit extensions. Capital costs to develop the new mine plan are estimated at $39.7 million, of which $20.9 million is for larger mining equipment. The larger equipment is expect- ed to yield a unit mining cost 23% lower than the existing fleet. Iamgold Considering Adding Heap Leach at Essakane Mine Iamgold has announced positive re- sults from a prefeasibility study (PFS) of installing a heap-leach operation to process lower-grade mineralization at its Essakane mine in northeast Burkina Faso. Essakane currently produces about 390,000 ounces per year (oz/y) of gold from open-pit mining and CIL processing. The PFS contemplates added production of 72,000 oz/y from heap leaching over a period of 6.5 years, and total life-of-mine average production from Essakane of 471,000 oz/y over a period of 8.5 years. Throughput to the CIL mill would av- erage 12 million mt/y, and heap leach throughput would average 10 million mt/y to 2026. Life-of-mine cash costs are es- timated at $707/oz, and all-in sustaining costs are estimated at $946/oz. Initial cap- ital expenditures to develop the heap-leach operation are estimated at $155 million. Heap leaching would run in parallel to the existing CIL plant. Dedicated primary and secondary crushing circuits, tertiary crushing using a high-pressure grinding rolls (HPGR) unit, material handling and stacking conveyors, and a carbon-in-col- umn (CIC) adsorption plant would be in- stalled. Loaded carbon would be transport- ed to the existing plant for stripping and refining, where minimal infrastructure up- grade would be required. Where possible, the specified equipment would be same as is used in the CIL plant to improve main- tainability and reduce parts inventories. Additional major infrastructure includ- ed in the PFS are the leach pad, solution distribution and collection systems, solu- tion ponds, camp upgrade, and increased power generation capacity. Based on the PFS results, Iamgold has initiated work on a feasibility study to fur- ther optimize project design, secure long- lead equipment, and improve project economics, with completion of the study planned for the first quarter of 2019. The feasibility study also will evaluate addi- tional development alternatives, such as a gravity circuit upgrade and an increase in grinding capacity. This strategy aims to increase the throughput and recovery of the CIL and gravity circuits to bring addi- tional value to the processing plant. Mineral reserves at Essakane current- ly stand at 102.6 million mt at a grade of 1.17 g/mt gold containing 3.8 mil- lion oz of gold for CIL processing, and 61.9 million mt at a grade of 0.43 g/mt containing 845,000 oz of gold for heap- leach processing. Katanga Reaches Agreement With Gécamines Katanga Mining Ltd., together with its 75% operating subsidiary in the Democratic Re- public of the Congo (DRC), Kamoto Copper Co. (KCC), has entered into an agreement, effective June 14, with joint venture part- ner, DRC state-owned company La Générale des Carrières et des Mines (Gécamines) to terminate the legal proceedings brought forward by Gécamines and resolve KCC's previously disclosed capital deficiency. Under the agreement, Gécamines, Ka- tanga and KCC agreed on a recapitalization plan that will allow the reconstruction of the net equity of KCC and satisfy the re- quirements provided for by DRC corporate law. Gécamines will withdraw from the le- gal proceedings it started on April 20 in the Kolwezi Commercial Court to dissolve KCC. AngloGold Ashanti Receives Obuasi Environmental Permits AngloGold Ashanti has received environ- mental permits for the Obuasi gold mine from Ghana's Environmental Protection Agency, which the company said is an- other important milestone paving the way for the redevelopment of this large, high-grade ore body. The environmental permits relate to the Obuasi redevelop- ment project and its associated tailings and water infrastructure. This follows the parliamentary ratifications of the regula- tory and fiscal agreements that cover the redevelopment of the Obuasi gold mine. Part of the Essakane feasibility study evaluates improvements to the mill seen above at night.

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