TORONTO (miningweekly.com) – Zinc-focused, base metals mining company Trevali Mining on Thursday reported that its Caribou mine and mill complex project remained on track and within budget, with commissioning still expected to start in the first half of next year.
The Caribou zinc/lead/silver mine and mill complex, located in the Bathurst Mining Camp of New Brunswick, was expected to produce about 93-million pounds of zinc, 32.5-million pounds of lead, 3.1-million pounds of copper, 730 000 oz of silver and 1 500 oz of gold a year.
Vancouver-headquartered Trevali said that the new 3 000 t/d semiautogenous grinding mill and associated components had been installed and the mill would be commissioned over the first three months of 2015.
The Xstrata process support group had inspected the three IsaMills installed at Caribou and had been found to be in excellent condition for start-up. The company noted that it was proactively replacing the electric motor bearings for enhanced reliability during commissioning and going forward.
The zinc and lead flotation circuits had been cleaned and repaired where necessary, and the copper circuit design and tendering was nearing completion.
All the mill’s motors and electrical drives were cleaned and serviced by original equipment manufacturer representatives.
Further, Trevali reported that the majority of the pumps had been refurbished and/or replaced and spare pumping capacity components had been sourced from the nearby Brunswick-12 mine and mill complex that was shuttered in 2013.
Plant instrumentation refurbishment was also ongoing as equipment became available and remained on track to be commissioned together with the mill.
In terms of underground development, Trevali said construction of the new portal started early in November and was advancing to schedule. The tunnel was expected to break the surface 100 m from the fine mineral bins in the first quarter, reducing the previous overland haulage route by about 1.5 km.
This, Trevali said, was expected to result in lower haul costs, improved underground fleet availability and improved winter production capabilities.
Meanwhile, about three years of underground development was in place, Trevali reported.
The ramp and level rehabilitation were about 90% complete and access to two of the first four production areas was about 75% complete. The third and fourth production zones were 40% to 50% complete and continued to progress to schedule and plan. There was currently about 600 000 t of mineralised material available for production.
The surface crusher was currently being installed to a newly designed radial stacking pad. Based on the company's experience with commissioning the Santander zinc/lead/silver mine, Trevali was currently planning to stockpile about 60 000 t to 80 000 t of underground material before starting the second-quarter mill-commissioning activities.
The mine’s main dewatering pumps were fully installed, dewatering the site at a rate of about 2 271 l a minute. The mine is currently dewatered to about 250 m below surface.
The underground paste backfill study was also advancing and results were expected in the first quarter, Trevali said.
Other surface activities were also progressing, including refurbishing the zinc/lead concentration shed, and replacing several bridges on site to improve access to the tailings management facility. The reclaim pumping station and water polishing pond areas had been raised and placed on new foundations in anticipation of potential future expansions to the facility.