When reoccurring failures at the tailings pumping station raised concerns about reliability and and safety, Capstone Pinto Valley Mine ask CGK Consulting Group to perform a Root Cause Investigation and make recommendations to prevent future failures and eliminate the risk to personnel.
It was determined that that over pressure events had been occurring during the starting and stopping of parallel pump trains, resulting in the sheering of pump casing bolts and cracks in the pump casing itself. In addition to the resulting downtime, Capstone was particularly concerned with the safety of plant operators since the bolts had sheered with such tremendous force.
CGK investigated the incidents by gathering historical data from the plants process information system, analyzing the mechanical design, interviewing plant operators and maintenance personnel, and by reviewing the process control code. After performing a detailed review, CGK made several mechanical design and process control strategy change recommendations. The recommendations were aimed at improving the functionality of the system to prevent the high pressure scenario and mitigating risk to operators by preventing the need for manual intervention. Through a handful of minor mechanical design changes, training of operators and maintenance personnel, and improvements in process control programming, CGK was able to completely eliminate the problem.