Microbiologically induced cable bolt corrosion in underground coal mines

Abstract

Corrosion failure is one of the serious concerns with most metal products. In the mining industry, corrosion failure of cable bolts may threaten the safety of operations and cause significant financial losses. In recent years, many cable bolt failures have been reported from several underground coal mines in Australia. Recent studies have shown that the localised environment around the cable bolts (oxygen level, groundwater, bacteria, etc.) has a significant impact on the corrosion behaviour; however, studies on the role of bacteria in the corrosion of underground support systems are still limited. This paper reports on a study of the role of a well-known bacterium in microbiologically induced corrosion of cable bolts. Acidithiobacillus ferrooxidans is found in many underground mines. The cable bolt specimens used in the study were specially designed to simulate the stress level experienced in the in situ mine condition. The specimens were analysed based on their weight loss and morphological features at the end of the study. The results indicated that the involvement of the bacteria in localised corrosion development and biofilm formation on the metal surface was a contributing factor in accelerating the corrosion of the bolt and could lead to catastrophic failure of the bolts in the long term.