An underground niobium mine was in need of a new 25,000-volt electrical distribution system for 4,160- and 600-volt power supplies at the mine’s Level 2400. Niobec’s mine, located in Saguenay-Lac-Saint-Jean, approximately 200 kilometres north of the Québec City, is the world’s only underground niobium mine, and one of the world’s three main niobium producers. The mine’s current production accounts for approximately 8 to 10% of global production, depending on demand in the nobium market.
Design a system that meets the following requirements:
- A 25-year system life;
- Fully redundant distribution and new infrastructure for communications with the surface through two electrical rooms supplied by two vertical and straight boreholes measuring 8 inches in diameter;
- Rooms cooled with service water;
- Distribution equipment designed for transport by ramp;
- Electrical distribution panels located on the surface;
- Detail and procurement engineering for equipment;
- Procurement engineering; and
- Cable-lowering plan preparation and installation supervision.
Performance and results
- Two 7.5-MW redundant electrical rooms. Electrical equipment was selected to facilitate installation in this constrained environment;
- Transmission by backbone wiring without a landing stage over a 2,400-foot descent;
- New, redundant optical fibre telecommunication infrastructure without additional drilling.