Engineering & Mining Journal

AUG 2018

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REGIONAL NEWS - AUSTRALIA/OCEANIA 20 E&MJ • AUGUST 2018 www.e-mj.com Century Mine Advances Toward Production New Century Resources, an Australian base metals development company, pro- vided an update on its efforts to restart the Century mine in Queensland. The company will reprocess tailings and is up- grading the existing infrastructure, which includies a large-scale, multitrain flota- tion plant, 700-person camp, private air- port, mining fleet, grid power connection, slurry pipeline and port facility to bring the mine into production. During its 16 years of operation, Cen- tury was one of the largest zinc mines in the world, producing and processing an average of 475,000 metric tons per year (mt/y) of zinc concentrate and 50,000 mt/y of lead concentrates at Lawn Hill. The product was transferred in slurry form via a 304-kilometer-(km) underground pipeline to Century's Port facility at Karumba. When processing operations ceased at Century in early 2016, New Century Re- sources spotted an opportunity to monetize the remaining mineral assets. These include more than 2.2 million mt of JORC compli- ant zinc metal equivalent resources located within tailings, and more than 1 million mt of JORC compliant zinc and lead resourc- es in the Silver King, South Block and East Fault Block base metal deposits. In addi- tion, Century hosts several substantial phos- phate deposits which were never developed. During July, hydraulic mining crews ar- rived on site and began preparing for min- ing activities. A slurry winning pontoon and infrastructure were installed in the tailings receival sump. A water winning pontoon was launched onto the evapora- tion dam. Electrical installation and dry commissioning were nearing completion. Processing plant refurbishment had been completed and full testing with water had been initiated. All circuits were loaded with reagents. The final tailings pipeline to the historical open-pit were installed and commissioned. All plant employees were onsite and making the transition from day shift only to 24/7 operation. New Century said it remains on track for first production in August. A set of 2018 concentrate shipping schedules have been established with offtake partners. The company hopes to eventually become one of the world's top 10 zinc producers. A comprehensive plan of work is also in place to progressively take the mine site, the pipeline and the port facility to full closure over a long-term period through to 2050. Restarting operations at Century, initially via tailings repro- cessing, allows much of the scheduled rehabilitation to be achieved through new cash-flow-generating site activities. After the tailings are reprocessed, the material will be pumped into the existing open pit, which allows for final encapsulation and eliminates the need for capping of the tailings dam on surface. It also significantly reduces the overall footprint of the disturbance for the Century mining operations, which should allow for a progressive reduction in the total finan- cial assurance surety required for the site. Boss Outlines Plans for Honeymoom Restart Boss Resources has launched a restart strat- egy for the previously operated Honeymoon in-situ leach uranium mine in eastern South Australia. Boss acquired the project in De- cember 2015 when it acquired Uranium One Inc. The project is expected to produce an average of 3.2 million pounds per year (lb/y) of U 3 0 8 , at an average life-of-mine all- in sustaining cost of $23.90/lb and cash costs of $15.60/lb of U 3 0 8 equivalent. The restart strategy will have three key phases: Phase 1 involves generation of final in- put data required for a definitive feasibility study (DFS), including a drilling program to deliver measured and indicated resources, an optimization program to deliver further cost savings and/or process improvements, and a preliminary execution plan, updated cost estimate, and schedule for the restart of the existing solvent extraction plant. Phase 2 comprises the DFS and per- mitting updates. Phase 3 covers detailed execution planning, operational readiness inclusive of a solvent extraction plant recommis- sioning plan, and detailed design work for a new ion exchange plant. Boss Resources Managing Director Duncan Craib said, "Phase 1 of the re- start strategy has commenced, and the company's initial activities are focused on the planning and preparation of the infill and step-out drill program. Consultants and engineering support for optimization and trade-off studies have been identified, and proposals are currently being finalized. "Being an in-situ recovery mine in combination with ion exchange produc- tion, the Honeymoon uranium project will operate in the lowest-cost quartile of worldwide producers," Craib said. Honeymoon has a JORC-compliant resource of 63.3 million lb of U 3 0 8 . Construction activities are nearly complete for hydraulic mining at the Century mine.

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