Freezing on demand: A new concept for mine safety and energy savings in wet underground mines

The artificial ground freezing (AGF) systems are designed to operate continuously for an extended period of time to control the groundwater seepage and to strengthen the groundwater structure surrounding excavation areas. This mode of operation requires a massive amount of energy to sustain the thickness of the frozen body. Therefore, it is of great interest to propose new concepts to reduce energy consumption while providing sufficient structural stability and safe operation. This paper discusses the principle of the freezing on demand (FoD) by means of experiment and mathematical model. A lab-scale rig that mimics the AGF process is conceived and developed. The setup is equipped with more than 80 thermocouples, flow-meters, and advanced instrumentation system to analyze the performance of the AGF process under the FoD concept. A mathematical model has been derived, validated, and utilized to simulate the transient FoD concept. The results suggest that the overall energy saving notably depends on the coolant’s temperature; the energy saving increases while decreasing the coolant inlet temperature. Moreover, applying the FoD concept in an AGF system leads to a significant drop in energy consumption.