Engineering & Mining Journal

DEC 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

Issue link:

Contents of this Issue


Page 24 of 115

REGIONAL NEWS - LATIN AMERICA DECEMBER 2018 • E&MJ 23 quired the project in May as part of its acquisition of Brio gold. The Santa Luz project has proven and probable open-pit mineral reserves of 28.2 million metric tons (mt), grading 1.39 grams/mt gold and containing 1.26 million ounces (oz) of gold. Gold production is es- timated at 1.06 million oz over an 11-year mine life at all-in sustaining costs of $856/ oz. Capital costs to complete and restart the mine are estimated at $82 million. Santa Luz will continue as a conven- tional truck-and-shovel, open-pit mining operation, utilizing a mining contractor. Processing throughput is planned at 2.7 million mt/y, or a nominal 7,400 mt/d. Gold recoveries are estimated at 84% from a blended feed of high-carbona- ceous material, low-carbonaceous mate- rial and dacite. The original processing plant at Santa Luz was based on carbon-in-leach (CIL) technology, which did not operate well, with low gold recovery rates from carbo- naceous ores. Subsequent metallurgical testing, including operation of a pilot-scale plant, has demonstrated that a switch to resin-in-leach (RIL) will be successful. The updated plant will include crush- ing and grinding, RIL, elution, and elec- trowinning. The crushing section is part of the original facility and requires only minor improvements. The grinding sec- tion will be upgraded to two mills oper- ating in series, the original SAG mill and a new ball mill. Most of the construction capital is related to installation of the RIL circuit, which primarily consists of a pre-aeration tank, two conditioning tanks, and five stirred RIL tanks in series. As a benefit from the prior operation, all of the major infrastructure require- ments for the project are already in place, including a 138-kV connection to the na- tional grid. The two tailings facilities will be modified: one facility will be expanded with the installation of a geomembrane liner to accept additional tailings from the new operation, while the second facil- ity will be modified to enable 2 million m 3 of water storage. The long-lead-time major equipment required for the project has already been purchased and is on site, including the new ball mill, cyclones, leach tanks, leach tank agitators, screens (inter-tank, resin, and vibratory), electrowinning cells, elution heaters and columns, lime bin, and various pumps and samplers. All necessary licenses and permits are in place for construction and resumption of Santa Luz operations, with only minor adjustments needed with respect to the updated plans for modifying the existing tailings facilities. In addition, Leagold Mining has re- started the RDM mine in Brazil. The decision follows an unscheduled shutdown that began in early October due to region- al drought conditions. As announced on November 13, the water storage facilities at the RDM mine had sufficient volumes to support the restart of operations and RDM commenced the recall of its work- force. As of November 20, the RDM pro- cessing facility was operating at its normal 7,000-metric-tons-per-year capacity. RDM began production in 2014 and Leagold acquired it from Brio Gold in May. Located in Minas Gerais state, about 560 km north of Belo Horizonte, it's a conventional open-pit mine with a carbon-in-leach plant. Average life-of- mine production at RDM is estimated to be approximately 98,000 ounces per year of gold over a nine-year mine life. Centaurus Divests El Conquista Iron Ore Centaurus Metals has divested its Con- quista Iron Ore Project in southeast Brazil to privately owned Brazilian mining group, continuing value realization process from its Brazilian iron ore portfolio. The transac- tion is consistent with the company's cor- porate focus on base metal exploration in the world-class Carajás Mineral Province of northern Brazil, the company said. Under the terms of the agreement, R3M will pay R$500,000 to Centaurus in mid-December and has also granted the company a 12% production royalty on all future production from Conquista and a number of surrounding exploration tene- ments which are prospective for iron ore. As part of this arrangement, Centaurus will receive an upfront payment of R$1.5 million on the commencement of produc- tion from Conquista as an advance of the production royalty. Centaurus Managing Director Darren Gordon, said the company was pleased to be able to crystallize value from the sale of the Conquista Project to R3M, with the privately owned group being ideally placed to take the asset forward given the ownership group is already operating in the immediate region at the nearby Can- donga DSO Project, which was acquired from Centaurus in 2016. "R3M understand the domestic iron ore and pig iron markets and see the po- tential to bring niche DSO assets into pro- duction relatively quickly," he said. "Im- portantly for Centaurus, we will maintain exposure to the success of the project and its potential future cash flows via a strong production royalty. Horizonte Advancing Long-life Ferronickel Project in Brazil Horizonte Minerals has reported the re- sults of a feasibility study of its wholly owned Araguaia ferronickel (FeNi) proj- ect in the southeast of the Brazilian state of Pará, approximately 760 kilometers (km) south of the state capital, Belém. The project comprises an open-pit nick- el laterite mining operation followed by a metallurgical plant based on rotary kiln electric furnace processing. Mining would produce 27.5 million metric tons (mt) of plant feed over a mine life of 28 years. The plant would produce 52,000 mt per year (mt/y) of FeNi, con- taining 14,500 mt/y of nickel, for sale to the stainless-steel industry. Capital costs to develop the project are estimated at $443 million, including $65.3 million for contingencies. The processing plant and project in - frastructure will be constructed over a 31-month period. After an initial ramp-up period, the plant will reach full capacity of approximately 900,000 mt/y of dry ore feed. The FeNi product will be transport- ed by road to the port of Vila do Conde for shipping to overseas customers. The feasibility study design allows for future construction of a second rotary kiln electric furnace line, with potential to double Araguaia's production capacity to 29,000 mt/y of contained nickel. Horizonte has obtained the prelim- inary environmental license and water permit for full-scale operation at Araguaia and is on track to obtain its construction license in the first quarter of 2019. The Araguaia project has two prin- cipal mining centers, Araguaia Nickel South and Araguaia Nickel North. Ara- guaia Nickel South hosts seven deposits: Pequizeiro, Baiao, Pequizeiro West, Ja- cutinga, Vila Oito, Vila Oito East and Vila (Continued on p. 38)

Articles in this issue

Links on this page

Archives of this issue

view archives of Engineering & Mining Journal - DEC 2018