Corrosion properties of ASTM A615 rock bolt steel in US underground coal mines

Corrosion of rock bolts is a relatively slow process yet a potential problem for the underground mining industry. Mine groundwater in the strata through natural or mining-induced cracks together with the humid environment in the mine openings interact with the roof support systems often resulting in corrosion. Electrochemical studies of the commonly used rock bolt steel in the coal mining environments will lead to a better understanding of the material's performance and their ability to resist corrosion. The influence of pH, solution resistivity, total dissolved solids, and aggressive ions on the electrochemical properties of rock bolt steel are discussed. This preliminary study focuses on understanding the corrosion potential, polarization resistance, and corrosion rates of the rock bolt steel that is most commonly used in US underground coal mines. Based on the findings, it was observed that the polarization resistance (Rp) is inversely proportional to the corrosion rate (CR) over time.