Northcliff Resources has received a positive feasibility study from Samuel Engineering for its 100%-owned Sisson tungsten-molybdenum project in west-central New Brunswick. The study confirms the technical and economic feasibility of an open-pit project producing an average of 557,000 metric ton units (mtu/y) of WO3 contained in ammonium paratung state (APT) and 4.1 million lb/y of molybdenum contained in concentrates over a 27-year mine life.
Average annual production in the first five years of operation is forecast at 689,000 mtu of WO3 and 4.4 million lb of molybdenum.
The Sisson project is located 100 km by road northwest of Fredericton, New Brunswick. The property hosts a 334-million-mt proven and probable mineral reserve containing 22.2 million mtu of WO3 and 154.8 million lb of molybdenum at a C$8.83/mt net smelter return cut- off. The average life-of-mine head grade is estimated at 0.073% WO3 and 220 ppm molybdenum.
Average life-of-mine recoveries are estimated at 77% for tungsten and 82% for molybdenum.
Initial capital expenditure to develop the Sisson project is estimated at C$579 million. Construction is expected to take 24 months to complete.
Infrastructure and facilities at the Sisson mine site will include an open pit, crushing, conveying, ore stockpile, ore concentrator, APT plant, tailings storage facility, and ancillary buildings including offices, shops, and warehouses.
Conventional mining equipment will be used, including 16.5-m3 electric-hydraulic shovels, 136-mt-capacity haul trucks, and 165-mm-dia hydraulic drills. The mine will deliver 10.5 million mt/y of mill feed to the primary crusher located adjacent to the pit. Mill feed will then be conveyed approximately 1 km to the concentrator. Lower-grade and non-mineralized material will be stored within a tailings storage facility.
The average mining strip ratio will be 1:1. Mill throughput will average 30,000 mt/d.
Mineral processing will consist of crushing and grinding to liberate the molybdenum and tungsten minerals, followed by flotation to recover the minerals into their respective concentrates. The crushing circuit will include a primary gyratory crusher, secondary cone crushing, and tertiary high-pressure grinding rolls, followed by single-stage, two-line ball mill grinding. Ground ore will feed the molybdenum and tungsten flotation circuits.
The molybdenum concentrate will be sold to other parties for further processing, while the tungsten concentrate will be further processed on site into APT. The APT plant will be the first of its kind in Canada.