John Crane has retrofitted a mechanical seal on a large underflow thickener slurry pump at a major copper mining operation, cutting the clean water needed for sealing by around 288,000 litres per day.
Underflow thickener pumps are a key link in tailings handling, moving high-density slurry from the thickener into the tailings transport system.
In this application, the Warman 550 pump operates at approximately 65% solids, where reliability is essential and any unplanned interruption can have an immediate impact on production.
Prior to the retrofit, the pump used a traditional stuffing box (packing) arrangement. In abrasive service, that approach led to accelerated wear on the shaft sleeve, with replacement required around every four months.
Although the impeller and rubber liners were typically replaced annually, sleeve change-outs were major events involving a full mechanical crew working across two shifts (around 36 hours), a 100-tonne crane, and extended exposure to safety and downtime risk.
John Crane designed a mechanical seal package to be installed at the rear of the pump replacing the original stuffing box (packing) arrangement and enabling a retrofit without modifications to the pump.
Following installation and commissioning, the sealed pump is operating well. The seal-flush system was designed around approximately 11 m³/h at 75 psi, with actual operating flow running at approximately 7.5–8 m³/h.
“Underflow thickener pumps are among the most critical assets in a mine’s tailings circuit, so customers are understandably cautious about change,” said Warren Smith, global mining market director, John Crane. “This project is a practical example of how improved sealing can reduce maintenance exposure and cut the clean water required for sealing, while supporting more predictable planned maintenance.”
John Crane retrofit saves around 288,000 litres of sealing water per day on critical pump
