A simulation-based method to optimise ice plant production in deep-level mines

Abstract

Deep-level mines have large heat loads and as the depth and scale of the mine increases, so do the heat loads. Artificial cooling methods are introduced to keep mines below the legal wet-bulb temperature limit of 32.5 °C. One artificial cooling technique involves utilising ice plants to supply a steady flow of ice into the mine. These ice plants are typically employed in mines surpassing depths of 2 000 m. Ice manufacturing plants on deep-level gold mines lose efficiency over time, and due to their complexity, it is difficult to identify the causes. Ice plants will therefore have lowered production, which reduces their overall cooling capacity. A method to identify and solve these problems is crucial in increasing the cooling capacity of ice plants, which is essential in mitigating the rising heat loads encountered in deep-level mines. The method was constructed and tested by making use of a case study methodology. Initially, a method based on literature was created and tested on an ice plant network. Thereafter, improvements were made by including a simulation model, facilitating more precise problem identification. By using this refined method, a bottleneck in the water chilling phase was identified on a case study. Addressing this inefficiency is anticipated to yield an ice production increase of 15.8% on Mine A, which is an annual energy value of R 5.03 million. When extrapolated to Mine B, an annual energy saving of up to R 15.09 million could be expected. The method serves as an investigative tool for pinpointing inefficiencies within an ice plant network, which enables potential resolutions to increase ice production.