John Crane's Water Saving Management For Copper Mining

A mechanical seal retrofit at a copper mine could cut clean water use for pump sealing by approximately 288,000 litres per day. John Crane installed the seal on an underflow thickener slurry pump at an operational copper site.

The water saving figures, if replicated across mining operations, could mean substantial reductions in an industry operating under water scarcity pressures. Copper mining concentrates in regions where water supplies face serious constraints.

The technology addresses a specific but widespread operational challenge.

Traditional sealing methods for slurry pumps require continuous clean water flushing to prevent equipment failure and maintain processing efficiency. As mining operations expand and water availability contracts, the cumulative effect of these seemingly minor water demands becomes increasingly significant.

Water scarcity in mining regions

Copper deposits cluster in areas experiencing extreme water stress. The Atacama Desert in Chile hosts major copper mines yet receives under one millimetre of rainfall annually on average.

Zambia and the Democratic Republic of Congo face water management challenges. Mining operations in these territories compete with local communities and agriculture for finite resources.

The competition for water resources creates operational and social risks. Communities dependent on the same aquifers and water sources as mining operations face supply pressures that can escalate into regulatory intervention or social conflict.

Regulators in water-scarce regions are tightening requirements for industrial water use. Investors are questioning the operational and geopolitical risks associated with mining in these areas.

Copper ore processing consumes water at nearly every stage. A large operation can use millions of litres daily for grinding, flotation and tailings management.

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The processing circuit relies on water not just for ore separation but also for equipment cooling, dust suppression and tailings transport. Each function draws from the same constrained supply, making efficiency improvements at any point in the circuit operationally valuable.

Mechanical seal replaces traditional packing

The underflow thickener pump moves dense slurry at around 65% solids from the thickener base into tailings transport systems. Equipment failure at this point can cause processing backups and operational downtime.

The pump previously used a traditional packing arrangement. This consisted of compressed fibrous rings around the shaft to prevent leakage.

In abrasive slurry applications, packing wears rapidly and requires constant clean water flow. The water flushes solids from the sealing point and provides cooling.

The constant flushing requirement means that even when a pump operates efficiently in other respects, the sealing system continues to consume clean water at rates that accumulate across continuous operation. This consumption occurs regardless of whether the pump is processing ore or running at reduced capacity.

John Crane replaced the packing with a mechanical seal. The seal comprises two precision-machined faces pressed together to form a near-zero leakage barrier, with one face rotating with the shaft and the other stationary.

The retrofit package required no modifications to the pump itself. An adapter sleeve was fitted to suit the shaft dimensions.

The seal uses a controlled flush arrangement to maintain clean fluid conditions at the seal faces. Diamond-faced materials provide protection if flush pressure drops and solids enter the seal chamber.

According to John Crane, the 270mm shaft diameter makes this the largest slurry seal the company has sold to date.

Water and maintenance reductions

According to John Crane, the sealed pump uses approximately seven and a half to eight cubic metres of water per hour for sealing. A pump at the same site running traditional packing consumes around 20 cubic metres per hour.

The difference of roughly 12 cubic metres per hour equates to approximately 288,000 litres of clean water saved daily. The figures are based on a single pump comparison at the site.

The retrofit also reduces maintenance frequency. The new seal is designed to need replacement only during the site's annual major service interval, when impellers and liners are changed.

The previous shaft sleeve required replacement every four months. Each replacement needed a full mechanical crew, a 100 tonne crane and around 36 hours of work across two shifts.

Warren Smith, Global Mining Market Director at John Crane, says the project demonstrates what improved sealing could deliver.

"Underflow thickener pumps are among the most critical assets in a mine's tailings circuit, so customers are understandably cautious about change," says Warren.

"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."

Implications for operational sustainability

A single pump retrofit shows water reduction potential, but the scale opportunity becomes clearer when considering full mining operations. A large copper mine can run dozens of pumps handling abrasive slurry across processing circuits.

Many of these pumps could still operate with traditional packing arrangements. Applying the same retrofit across a pump fleet at one operation could deliver water savings in the millions of litres daily.

In territories like the Atacama, Zambia and the Democratic Republic of Congo, water supplies are finite and under pressure. Reductions of this scale could affect both operational costs and regulatory compliance.

The operational case for water efficiency extends beyond environmental reporting. Water scarcity translates directly into production constraints when supplies become unavailable or when regulatory limits restrict extraction. Efficiency improvements that reduce water demand per tonne of ore processed provide operational resilience against these constraints.

John Crane operates as a division of Smiths Group, a FTSE 100 industrial technology company with operations across more than 50 countries. The global footprint could allow deployment of this technology across multiple jurisdictions and operating environments.

The retrofit does not resolve mining's overall water challenges. However, the results suggest that operational upgrades could contribute meaningful reductions without relying solely on corporate sustainability commitments.