Insulation of deep and hot mines as a means of reducing heat loads

The management of heat is a significant challenge for the deep mine environment. Geothermal heating through the rock walls in the mine is a major contributor to this heat. One potential approach to decrease the contribution of this heat source, and therefore reduce the energy required for cooling, is to insulate rock walls in order to reduce heat flux into cooled spaces. This research addresses the viability of various materials for this application, the performance of the insulation and the cost-benefit of the strategy. The results of previous studies on heat reduction through rock insulation are examined and found to be encouraging.;An experimental study was conducted in order to evaluate the initial feasibility (ease of application, adhesion of insulation to surface, etc.) as well as the performance of a new candidate material for mine insulation. The experiments evaluated the application, working performance and thermal properties of the insulation material. The tests found that the material has the potential to be used for underground hot conditions and has thermal conductivity of 0.065 W/m2 K at 80°C. Also, this initial investigation found that the material presents a logistical advantage from an ability to apply both ground support and insulation using the same equipment and base materials.;In this work, time dependent (transient) analysis is performed to quantify the heat reduction at 50°C virgin rock temperatures. A number of computer simulations to review the impact of various parameters on insulation performance are presented. The insulation is evaluated in the specific context of deep mines in the Sudbury Nickel Basin. Therefore, local factors such as geothermal gradient, nature of mine shafts, and surface ambient conditions will be taken into consideration. It was found that a reduction between 50% and 34% in heat ingress is possible through full and partial insulation of rock surfaces respectively. The magnitude of savings through insulation is influenced by numerous factors such as rock type, time of insulation application, virgin rock temperature, thickness and thermal conductivity of the insulation material.