Abstract
As high mine-cooling costs have become a restriction for deep mining, a new cooling method has been proposed. In the area of filling mining, the CPB (cemented paste backfill) was given the cooling function by mixing it with phase change material (PCM). In deep mines, the PCM (e.g., ice particles) absorb heat and change phases to cool the surrounding environment. A deep-mine-cooling mode based on the new CPB and upward sublevel filling method was designed, and the characteristics of the phase change were analyzed by numerical simulation. From the simulation results of the cooling period, this cooling method was effective during the whole stopes mining period. The CLS (cold load and storage) CPB mass concentration and the PCM initial proportion are the important factors controlling the cooling effect. It is concluded that the phase change duration decreased with the increasing mass concentration, while it increased with the increasing initial proportion of ice to water. Note that the thickness of CLS-functional CPB should be as small as possible to ensure the cold release rate. This study provides a theoretical foundation of heat transfer for the design and implementation of deep-mine cooling by applying CLS-functional CPB.
Highlights
The high geothermal environment in deep mines is one of the constraints in mining and is as important as high ground pressure and high seepage pressure (Guo et al, 2017; Yang et al, 2017; Zhang et al, 2018; Lin et al, 2019a)
Cold load and storage-functional cemented paste backfill (CPB) is a new cooling method, which could be applied to deep mine cooling
A 2-D, unsteady state heat conduction model compounded with a hydration heat model, a porous media model and an enthalpy method model was applied to simulate the phase change and heat transfer process of CLS-functional CPB in deep mines
Summary
The high geothermal environment in deep mines is one of the constraints in mining and is as important as high ground pressure and high seepage pressure (Guo et al, 2017; Yang et al, 2017; Zhang et al, 2018; Lin et al, 2019a). The literature (Wang et al, 2018) proposed the concept of CLS-functional CPB and indicated that it could provide cold regulation in deep mines but did not involve the calculation of the heat transfer of the cooling process. Heat transfer calculation research of this new CPB material was carried out, but it was launched in a small test box in the laboratory Based on these two works, the deep mining environment was considered, and the CLS-functional CPB was simulated to determine the cooling process and effect of the new CPB in this study. We focused on the heat transfer and phase change of CLS-functional CPB in deep mines and applied an enthalpy-porosity-hydration heat transfer model for research.
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