There’s a lot of lead-zinc ore at Ruddock Creek and they keep finding more.
That was the report that Imperial Metals exploration manager Jim Miller-Tait brought to District of Clearwater council during its Dec. 4 meeting.
“We wanted at least 10 million tonnes. That’s the threshold and we’ve got that,” he said. “At these grades, you’ll make $150 per tonne … all the partners are very happy.”
The proposed mine is located about 15 southeast of Tumtum Lake and about 30 km due east of Avola.
The ore has been found along a 5.5 km long massive sulphide horizon that runs through a mountain range east of Oliver Creek.
It was created by hot water moving under the bottom of the ocean near a limestone reef in Pre-Cambrian times. The limestone means that the host rock that contains the ore consumes acid. This contrasts with most lead-zinc mines, where acid leaching can be major problems.
“We’ve never had an acid water sample,” Miller-Tait said.
The ore body has gone through extensive heating over the years, which means that harmful metals, such as mercury, cadmium and selenium, were heated out.
This makes the ore attractive to smelters in Japan, he said. Regulations there restrict the contaminants found in ore that is imported into that country.
The configuration of the ore body means the mine would be an underground operation, rather than open pit. Cost of an underground mine is about $40 per tonne, compared to $1.50 per tonne for an open pit operation.
In 1960 Falconbridge Mining found the E-zone ore body, which is located at the east end of the sulphide horizon, Miller-Tait said.
The company spent the next three years exploring it but then developed other priorities.
Cominco conducted more exploration from 1975 to 1977.
Beginning in 2004 Selkirk Metals, a company Miller-Tait helped set up, explored the ore body.
A crucial turning point occurred in 2005 when they found where the E-zone continued beyond a major fault.
The upper E-zone, which was where nearly all the exploration to date had been done, contains only about 2.5 million tonnes of ore, he said. This would not enough to justify a mine.
They lowered a geophysical sensor down a drill hole and used it to locate the lower E-zone, which was about 200 m lower and at a radically different angle.
“If we hadn’t found that, we wouldn’t be here today. It made all the difference,” Miller-Tait said.
They drilled into the lower E-zone to confirm its location, and later punched a tunnel or decline (now over 1.3 km long) into it.
Since then they have made more tunnels from the end of the decline in a T-shaped configuration, and used them as a base to drill more holes into the lower E-zone.
Selkirk also discovered the Creek and U-V-Q zone extensions further west along the sulphide horizon.
Imperial Metals took over Selkirk in 2009. Imperial is what Miller-Tait called a “mid-tier producer.” It has two operating mines: Mount Polley, a copper-gold open pit mine near Williams Lake, and Huckleberry (50 per cent interest), a copper-molybdenum mine near Smithers). It also has several projects still in the exploration or development stage, including Ruddock Creek.
Two Japanese companies, Mitsui Mining and Smelting and Itochu Corporation, have been financing much of the Ruddock Creek project over the past few years and soon will together have a 50 per cent interest in it.
Access to the remote location is an issue. Driving there is usually by logging road from Vavenby and takes several hours. Making a more direct route from Tumtum Lake to near Avola would save about 45 minutes on the drive.
Electric power is also an issue. One possibility would be to make use of the power infrastructure still in place from a now abandoned mine near Mica Dam to the east.
There is presently a 40-person camp at the site. Construction would employ about 300 people while production would provide about 200 jobs. Because of the location the work-site would be a camp situation, the exploration manager said.
Miller-Tait felt Imperial Metals is close to having enough information to conduct a preliminary economic assessment, and might even skip the usual pre-feasibility study and go straight to a feasibility study.
The proposed lead-zinc mine at Ruddock Creek is one several mineral developments in the area. Another is the copper-gold-silver mine proposed by Yellowhead Mining at Harper Creek, which is about 10 km southwest of Vavenby. A third is Commerce Resources tantalum-niobium project north of Blue River.