Abstract:

Acid mine drainage (AMD) is the prominent environmental pollutant in the resource extraction industry. AMD primarily affects aquatic environment’s due to its liquid form, highly acidic nature and ability to readily dissolve heavy-metals common to mining, such as Hg and Cd. Iron oxides and hydroxides are produced as a product of AMD production. These substances can precipitate out, creating an orange precipitate called ochre. Due to ochre’s density, it accumulates on the bottom of stream beds, smothering primary producers and locking up available nutrients. Of the several hundred different types of sulphide-bearing minerals responsible for AMD production, pyrite-rich ore bodies are the most common. The typical process of AMD production involving pyrite is simple; however, to establish dangerous pH concentrations of 2.3 - 3.5, the reaction requires several right factors, including temperature, pH, water and free oxygen content, which are the most influential. Under normal abiotic circumstances, AMD is a very-slow self-limiting reaction. With the presence of clear sulphur-oxidizing chemolithotrophic bacteria, the otherwise slow self-limiting reactions turns into a swift autocatalysis reaction which may not stop for thousands of years. Little is known about these bacteria, which readily create pH environments of less than 2.0 and are extremely hard to culture due to their polyextremophile nature; however, they commonly exist within mine tailing ponds. This study works to combine current and previous research on sulphur-oxidating bacteria within AMD production to create a synopsis that will provide a centre of knowledge and identify ideas for future research and associated limitations.

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Clay Falk