Vale's Coleman mine, operating at depths reaching 1,850 m, could experience underground summer temperatures >40°Cdb/28°Cwb without cooling. Through 2019-20, BBE provided EPCM for a 10.3MWR vapour-compression cooling plant that allowed 15% ambient air mixing. The footprint was restricted on three sides: two rock walls and the existing surface intake fans/heater facility. The proximity of the new system design, immediately upstream, could not impact current performance.
CFD analyses, by Flowcare, were used to ensure the 6m set-back design of eight bulk air coolers (BACs), 4 wide by 2 high, did not impact flow or pressure of the existing fan/heater, or cooled air delivery efficiency. Seasonal operation requirements, wind effects, and mitigations were considered. Configurations evaluated included: base case (no cooling plant), permutations of the BAC design, and cross winds up to 30km/h.
The CFD analyses showed negligible aerodynamic impacts and minor influence on the fan's 2kPa total pressure and 566m3/s flow; but wind effects potentially caused up to 40% cooling loss. The addition of side-shields, currently being installed, and BAC fan deflectors were shown to reduce the loss to a maximum of 6%. This paper discusses the CFD modeling, incremental design improvements, and system performance data gathered to date.
