Water balance development for legal compliance of gold mines in South Africa

Abstract

South Africa is experiencing water scarcity due to the increase in water demand and decrease in water supply. A predicted shortfall of 17% by 2030 is prompting stricter enforcement of the National Water Act number 36 of 1998, compelling all large-scale water users to obtain a water use license. One of the main requirements for a water use license and the application thereof is a detailed, accurate water balance. For a water balance to be compliant, it should be sufficiently detailed and accurate within 10% over a process unit and 15% per mining operation. Numerous gold mines in South Africa do not have water use licenses, leaving them vulnerable to possible consequences such as mining activities which are forced to stop. Existing water balances of gold mines are also not compliant with the regulations set out by the Department of Water and Sanitation, making the application process for a water use license difficult. This thesis focuses on the development of a water balance methodology that can be applied to any water system at a gold mine. The methodology aims to produce water balances that are fully compliant and practical for use in the gold mining industry. Process units of the gold mining process are developed as modules which can then be linked to complete the flow for any water balance system. These process units include shafts, processing plants, tailings storage facilities, water bodies, backfilling plants, and waste rock dumps. The application of this methodology was done on a gold mining operation in South Africa. After applying this methodology to the mining operation, accurate and detailed water balances were obtained that are all within a 10% variance over a process unit and 15% over the mining operation. These water balances are therefore fully compliant with the requirements for a water use license set out by the Department of Water and Sanitation. Water use licenses are becoming increasingly important for South African gold mines. Detailed and accurate water balances are a mandatory requirement in the water use license application process. The methodology developed in this thesis proves to deliver water balances that are detailed and accurate and comply with all the requirements for a water use license application.