A large copper mine in Mexico faced government fines and a potential shutdown from rotating equipment process fluid leaks. An audit determined the leaks were coming from the rotating equipment’s seals used in the electrolysis and flotation copper ore extraction processes, discharging as much as three gallons per minute. The tailing water was comprised of 60% water, 12% copper and 28% sulfuric acid, which had a significant impact on the environment. Correcting the leakage problem required a substantial remedial effort and an outside expert to plan and execute.
John Crane’s Expertise
Mine management looked to John Crane for a solution to eliminate the leaks at a cost far less than the potential fines and production losses caused by a suspension of operations by the government. The analysis uncovered the seals were damaged because of the caustic nature of the process fluid as well as hydraulic shock, also known as the water hammer effect, from frequent starts and stops. The most economical solution was to modify the piping plan to a 53A, including John Crane seals, lubrication plans and installation service.
Sealing Solution
The modified sealing system included 46 John Crane Type 5620VP dual pressurized cartridge seals incorporating ear drive O-ring pusher seal heads, as well as 46 five-gallon reservoirs for the Plan 53A piping plan. The reservoirs provided barrier fluid for the dual seal arrangement pressurized to 10 PSI to accommodate pump flow rates of 15,000 to 17,000 gallons per minute. Reservoir cooling coils were used to reduce heat and a lubrication plan was implemented to provide positive flow and pressure to prevent freezing.
Dramatic Results
After three years, the mine has recorded zero emissions of process tailings fluid, eliminating government fines and production shutdown threats. The combination of eliminated seal leaks, reduced labor costs and trimmed spare parts expenses is saving the mine more than $50,000 per year.
Source: https://resources.johncrane.com/case-studies/cs-pressurized-seali?lx=w--jPB