Client: Climax Mine
Location: Leadville, Colorado
Description: The Climax Mine located outside of Leadville, CO at an elevation of 11,500 feet had been closed since 1995. After an initial attempt at reopening the mine in 2008 construction began again in the beginning of 2011 including the construction of a new dual fed 115kV substation with twin 30/40/50 MVA transformers that feed a 13.8kV switchgear.
NEI was contracted to design the “front end” of the substation including a little over a half a mile of 115kV double circuit transmission line. NEI provided both civil and electrical design of the 115kV portion of the substation including grading, foundations, elevations, trench/conduit plans, wiring diagrams, system protection, control, and cable schedules. NEI also provided substation SCADA that connects directly to the mines SCADA system to provide monitoring and control to mine operators.
The project was located at over 11,500 feet above sea level and has an annual snow fall of roughly 20 feet. Special consideration was provided for snow accumulation and more importantly providing additional investigation and design into installing electrical equipment at this altitude. Additionally, the Climax Mine has a large instance of thunder storm activity during the summer so lightning protection was of particular concern. The double circuited transmission line was designed at two different voltage levels to reduce the possibility of a flash over on the line in the case of a lightning strike.
The substation site itself was constructed on over 20 feet of back fill taken from spoils piles left over from earlier mining activities. This created special conditions for both the design of the foundations as well as the design of the ground grid. The grounding conductors were incased in a conductivity enhancing material to provide both protection from the acidic soil as well as providing a better path for ground fault current to travel.