A strategy for potable water conservation in gold mines

Abstract

Water is a valuable resource in South African communities as well as industries. Mining operations require water for a variety of applications. The mismanagement of water results not only in the industry losing revenue but also in depleting South Africa’s water resources. Mines make use of large quantities of both potable and non-potable water. Potable water is good quality water and a shared resource between communities and industries. Correct implementation and improvement of present mine water management strategies can reduce potable water usage in gold mines. Mining operations have used several methodologies to improve potable water conservation. However, these methodologies focus on installing water treatment plants instead of water conservation practices, and even though this strategy to reduce the reliance on potable water from external sources has been proven to work, it is expensive and requires intensive maintenance. The installation of water treatment plants does not address the root cause of the high potable water usage in the mining industry. Improved water conservation practices can, therefore, postpone the need for investments towards water treatment facilities. Literature shows that water conservation strategies require an integrated approach to saving water which includes the development of water balances, reporting water use, monitoring equipment conditions and recycling used mine water. Most literature focuses on recycling water; however, this is not the only solution to water conservation. Benchmarking operations and systems visually enables mine managers to realise water misuse and thus save water within the system effectively and efficiently. This will assist mines to identify segments in the mine that require more attention regarding water management and conservation. Mines are traditionally benchmarked based on the mineral mined i.e. gold, platinum, copper, and others. This is because potable water needs for gold mines are different from those of platinum mines. The amount of mineral processed or mined is not the only variable that affects water use. A variety of factors influence potable water consumption. In this study variables for benchmarking potable water use are evaluated and used to set suitable benchmarks. Benchmarking introduces the need for intensive data management. Understanding the management of mining water is data-driven due to the vast amount of measurements required. A holistic strategy that creates system performance awareness in terms of comparative water consumption was required. A strategy that efficiently identifies key failing systems in gold mines was needed. The scope of this study is limited to gold mines, and a strategy that isolates business units within gold mines was developed. Data was collected for all relevant operations, verified, and normalised by identification of variables to establish suitable benchmarks. These benchmarks assisted in identifying water savings opportunities. These opportunities led to the implementation of correct conservation measures for specific business units. Eighteen mining operations were evaluated. The benchmarking methodology identified three key failing facilities that required further investigation into their water usage. These were the least performing operations. Water balances were developed to better understand the systems, various equipment was monitored and resulted in the identification of several leakages within the systems. A total water saving of approximately R17.7 million per annum was achieved and approximately 1 358 million litres of potable water was conserved per annum. The savings achieved are enough to provide more than 11 000 people in South African communities with water per day.