Practical implementation of the bacterial oxidation process of refractory gold ores

Abstract

The effective treatment of refractory arsenopyritic gold ore is of growing significance, especially in countries such as Australia where many of the more readily accessible oxide deposits are approaching depletion. Traditionally these ores were subjected to roasting to liberate the occluded gold, often with preconcentration by flotation.

Bacterial oxidation is gaining increasing application as an important viable treatment process for refractory ores, providing benefits in cost, performance, and environmental aspects. Design of current large scale bacterial oxidation plants has presented new challenges to the engineer, particularly in materials selections and construction techniques for handling the corrosive pulps at low pH levels and elevated temperatures.

Reference is made in this paper to the experience gained from the recently completed Wiluna sulphide project in Western Australia, which when commissioned was the world’s largest bacterial goldtreatment plant withfull sulphide oxidation.