Industrial mineral continues to profit for Teck, Cambior

Fifteen years after it first went into production, Niobec, the only underground niobium mine in the world and the only mine of its kind in North America, continues to turn out at a relatively low cost an industrial mineral which is sold into the international market.

Equal partners in the mining operation, situated in the Lac St. Jean area of Quebec, near Chicoutimi, and which was visited recently by The Northern Miner, are Teck (TSE) and Cambior (TSE). Vancouver-based Teck acts as operator of the mine, while Cambior, with headquarters in Val d’Or, Que., is responsible for marketing and sales of the niobium pentoxide (Nb2O5) concentrate produced.

Highly mechanized and equipped with modern mining machinery, Niobec operates at an extraction rate of 3,400 tons ore per day. The mine operates 24 hours per day, five days per week. Ore extraction is from between the 300-ft. and 1,000-ft. levels. Access to the six mining levels is via a 1,326-ft.-long shaft and/or by ramp.

Niobec, a relatively clean mine with some 160 workers, has reserves for at least 14 more years of production. The owners have obviously adopted a long-term strategy: a small grader was spotted smoothing the rampway during an underground inspection. Tour guide Jean Filion, Niobec’s general superintendent who has worked at the mine for 13 years, nimbly moved about the underground workings, which include a maintenance garage at the 450-ft. level, on a modified tractor.

The ore is mined from large open stopes 150 ft. long, 80 ft. wide and 300 ft. high. (At the time of the visit, a stope at the 700-ft. level was in preparation.) Crushed ore descends by gravity to the bottom of the stopes, from where the ore is loaded on to trucks for transportation to the ore pass, which directs the material to the crusher at the 1,150-ft. level. The ore is crushed to five inches in diameter and then hoisted, via the shaft, to the surface for milling.

In 1990, Niobec processed 875,500 tons of ore grading 0.71% Nb2O5 and produced about 7.5 million lb. of the concentrate.

The mill, which has been expanded since its 1976 startup but is still operating with mostly its original equipment, runs 24 hours per day, seven days per week. The rated capacity of the mill is 2,400 tons per day; at the time of the visit, daily throughput was averaging just under 2,500 tons.

Processing involves crushing, grinding, classification, desliming, magnetic separation, three types of flotation, leaching, two filtration stages and drying of the final concentrate. For the most part, the mill uses recycled water from the tailings pond. (Additional land has had to be purchased by the owners for expansion of the mine’s tailings operation.)

One ton of ore yields, on average, 14 lb. of concentrate containing an average eight pounds of Nb2O5. The end product is a concentrate of pyrochlore containing 60% niobium pentoxide, which is packaged and shipped in barrels.

In part because of the metallurgy involved, mill recovery has been an ongoing concern; in 1990, it was slightly better than 60%. “With the type of mineralization we have, that’s about the best we can do, but in the future we hope to improve it,” said Michel Robinson, mine manager.

Mill superintendent Noel Ayotte said he was hopeful plans to add an on-stream analyzer, to help speed up the processing, would be realized this summer. He said the cost to install the unit would be more than $500,000.

Robinson said the mine’s operating cost in 1990 was about $18 per ton.

Reserves at the end of 1990 stood at an estimated 11.1 million tons (proven and probable). Exploration drilling planned for this year will be in an area of suspected mineralization, Teck stated in its 1990 annual report; last year, limited exploration drilling was required for production scheduling purposes in a specific area of the mine.

Niobec ships its concentrate to three major customers in Japan, Great Britain and the U.S. The buyers convert the concentrate into ferroniobium, which is then sold to steel companies for the production of special alloy steels.

The steel industry is the largest consumer of niobium (also known as columbium). The alloys, combining strength and corrosion resistance, have numerous applications, such as in the manufacture of pipelines.