John Crane mechanical seal retrofit cuts water use at copper mine by 288,000 litres per day

John Crane has helped a major copper mining operation reduce sealing water consumption by around 288,000 litres per day after retrofitting a mechanical seal on a production-critical underflow thickener slurry pump.
The project involved replacing a traditional stuffing box packing arrangement on a Warman 550 pump used to transport high-density tailings slurry at approximately 65% solids concentration. The retrofit was completed without modifications to the existing pump and included the installation of a mechanical seal package and adapter sleeve.
Before the upgrade, the abrasive operating environment caused significant wear to the pump’s shaft sleeve, requiring replacement about every four months. These maintenance activities involved a full mechanical crew working across two shifts, the use of a 100-tonne crane, and extended downtime.
The new sealing arrangement incorporates a controlled seal-flush system designed to maintain a clean environment at the seal faces. Diamond-faced materials were specified to improve durability if seal-flush pressure drops and solids enter the seal chamber.
Following commissioning, the system has been operating at approximately 7.5–8 m³/h of sealing water, compared with around 20 m³/h consumed by a comparable packed pump. This equates to a reduction of roughly 12 m³/h, or approximately 288,000 litres per day, depending on site operating conditions.
The retrofit has also been designed to align maintenance requirements with the mine’s planned annual service interval for impeller and liner replacement.
“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.”
The installation also marks a milestone for John Crane, with the 270 mm shaft diameter representing the largest slurry seal the company has sold to date.