Spring is about a month away, and milder temperatures are just beyond the horizon as the end of winter runs its course. But although it seems like everyone is occupied with staying warm, that’s not always the case once you scratch beneath the (literal) surface. One mining company is planning on establishing an operation at an underground metal mine in Canada, and a major obstacle for them to overcome is an excess of heat at considerable depths. They contacted Mobile Air & Power Rentals looking for a temporary chilled water solution, and we were more than happy to take on the challenge.
The problem with underground mines is simply that they’re hot. Due to the geothermal energy of the rock mass being dug into, energy from mining machinery, and other potential sources of heat, underground mines can easily become too hot for workers to safely and efficiently run their operations. A practical approach to this problem is implementing a chilled water system as a cooling solution. This system utilizes a chiller to collect heat from the mine and somehow dump it into the atmosphere above the ground (to better understand how a chiller performs this task, check out our Chiller 101 series).
The temporary cooling solution that we designed for the mine called for no short list of equipment: one 240-ton water-cooled chiller, a specially made chilled water coil, two 600 GPM water pumps, two 750 GPM water pumps, and two 160-ton cooling towers. There were numerous considerations behind the specific capacities of the rental equipment as well as how they’d be staged in the mine, with the most important consideration being the placement of the cooling equipment itself.
Normally, in a moderately deep mine, condenser water could be pumped above ground where it would exchange its heat with surface level air. The mine that MAPR was asked to cool was far too deep for this kind of solution, however, as the height of the water pipe would cause an enormous amount of water pressure to overcome. Instead, we designed a solution where each and every component of the cooling system will be staged inside the mine, including the cooling towers. Because of this staging, the solution will utilize the mine’s ventilation system to ultimately expel unwanted heat to the surface. This placement also affected how we approached selecting equipment capacities.
In the depths of the mine, high humidity conditions mean that the wet bulb temperature is high relative to the dry bulb or “air temperature”. Essentially, the cooling effects of evaporation are limited due to the large amount of moisture already in the air. Considering that our cooling towers rely on evaporation to perform their role in the cooling system, this limitation required us to choose larger cooling towers, and to a lesser extent a larger chiller. In these hot and humid conditions, after all, a 100-ton cooling tower cannot provide the full 100 tons of cooling to the system. A larger cooling tower would need to be selected in order to make up for the limited cooling effect of evaporation.
With these considerations all accounted for, the temporary cooling solution is ready and on its way to the mine in Canada. Though we will not install the solution because of the restrictions and liability of working in a mine, we will be onsite to provide technical assistance for the customer while they perform their own installation. Once installed, the solution will provide a safe and comfortable environment that’s conducive to the overall mining operation.
