Prediction of Acid Neutralizing Potential of Wetlands Affected By Gold Mining in a Semi-Arid Area

South Africa's mining activities play an important role in ensuring the country's position in the global market. Unfortunately, the country’s mining history has also resulted in dramatic environmental consequences, particularly acid rock drainage (ARD) from gold mines of the Witwatersrand. This study aims to predict the acid generation potential from wetland environments affected by gold mining. Static acid base accounting (ABA) tests were conducted at an active gold mine tailings dam, where sediment samples were collected from both natural and constructed wetlands as well as from tailings materials from a century-old facility. The Sobek method was utilized for the ABA tests, alongside total metals and speciation analyses. Results revealed variable Net Neutralization Potentials (NNPs), indicating the need for kinetic tests. Natural wetlands generally displayed a higher acid forming potential than constructed wetlands, with findings suggesting that complete oxidation of samples would lead to acidic conditions. Furthermore, metal analyses highlighted concerning total metals values and significant correlations between reducible species and sulfur content. These insights underscore the potential for non-soluble metals to generate ARD once oxidized, contributing to acidification of water sources.