Engineering & Mining Journal

APR 2018

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REGIONAL NEWS - AUSTRALIA/OCEANIA 22 E&MJ • APRIL 2018 www.e-mj.com goorlie operations for total consideration of A$80 million ($63 million). The ac- quisition includes the project's operating processing facility, which has an annual capacity of 1.2 million metric tons (mt), a JORC resource of 4 million ounces (oz), including 250,000 oz in reserves and 800 square kilometers of prospective gold leases. The South Kalgoorlie opera- tions, located 50 km from Northern Star's Kundana operations, is currently produc- ing at a rate of 30,000-40,000 oz/y. The plant is also toll-treating ore for third par- ties. The transaction was expected to be completed April 1. The transaction amounts to A$60 mil- lion in Northern Star shares and A$20 million in cash. Northern Star Executive Chairman Bill Beament said the acqui- sition would be an economical means of ensuring the company met its 300,000- oz/y production target from organic sourc- es at its Kalgoorlie operations. "Our highly successful exploration strategy in Kalgoorlie has generated huge growth in our inventory and paved the way for us to grow production there to 300,000 oz/y," Beament said. "To capi- talize on this success, we were consider- ing the option of expanding our Kanowna Belle facility." He added, "The South Kalgoorlie processing facility is one of the best-run facilities in the district and is well with- in trucking distance of our Kundana Operations." Wafi -Golpu Feasibility Study Estimates $2.8B Initial Capital Newcrest Mining has released an up- dated feasibility study of the Wafi -Golpu copper-gold project in Papua New Guin- ea. The project is currently a 50/50 joint venture between Newcrest and Harmony Gold. The state of Papua New Guinea has the right to purchase, at a pro rata share of accumulated exploration expenditure, up to a 30% equity interest at any time before the commencement of mining. The updated feasibility study calls for extraction of ore via three stacked block caves to be mined sequentially from the top down at a design capacity of 17 million metric tons per year (mt/y). Ini- tial capital expenditures to commercial production are estimated at about $2.8 billion. Life-of-mine capital expenditures over a mine life of about 28 years are es- timated at $5.4 billion. The orebody remains open at depth, and ultimate life of mine is still to be de- termined. Average annual production of metal in concentrates is estimated at 161,000 mt/y of copper and 266,000 ounces per year (oz/y) of gold. The payback period is estimated at 9.5 years. Cash costs of copper production net of gold byproduct revenue are estimated at $0.26/lb. The proposed processing plant will in- clude on-site self-generation of bulk pow- er and associated fuel handling. A deep-sea tailings placement sys- tem has been identifi ed as the preferred method of tailings management, with tailings transferred via pipeline to the off- shore disposal site. A permanent accommodation facili- ty for rostered employees is proposed to house 1,400 people, along with a tempo- rary construction camp for 1,000 people. The Wafi -Golpu project is located ap- proximately 65 kilometers (km) south- west of the port city of Lae in Morobe province, Papua New Guinea. The pro- posed mine site sits at an elevation of about 200 m above sea level in moder- ately hilly terrain. Primary underground access would be via twin declines. The declines would also form part of the primary ventilation circuit and would house the materials handling system for conveying ore to the process plant on surface. During caving operations, ore from block cave drawpoints would be deliv- ered by autonomous load-haul-dump vehicles to underground crushers, with two crushers on each level. Crushed ore would be conveyed to the surface via dedicated conveyors. The proposed processing plant is a compact copper concentrator based on a fl owsheet that includes a semiautoge- nous grinding mill, two ball mills, and a recycle crushing confi guration; fl otation; thickening; and concentrate and tailings pumping systems. The facility is designed to recover copper and gold at life-of-mine averages of 95% and 68%, respectively. Concentrate grades are estimated at 29% copper and 15 g/mt gold. Concentrates would be delivered via pipeline to new port facilities at Lae. These facilities would be designed to handle, store, and export at a peak pro- duction rate 84,000 mt/month of wet copper concentrates. Newcrest Managing Director and CEO Sandeep Biswas said, "The im- proved business case set out in the up- dated Wafi -Golpu feasibility study clearly demonstrates the world-class nature of this multi-decade project. At Newcrest, we are excited to have this tier 1 asset in our portfolio with an IRR of 18%, fi rst quartile production costs, and decades of operating life. We have a clear pathway forward for the project, and together with our joint-venture partner, we are commit- ted to working with the government and people of Papua New Guinea to progress this world-class asset." The proposed mine design shows ore extraction from three block caves producing 17 million mt/y.

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