Innovation and best practices in Mining: Operations and Processing

Process Flow Optimization: Innovative Approaches to Sustainable Mining: Water Management, Safety, and Process Efficiency

Optimizing Underground Gravity Fed Process Water Reticulation Systems: A Vale Mines Case Study

Wayne Johnstone Victaulic

Abstract

Process water is an integral part of mining operations. Underground machinery requires water to operate, with most sites usage reaching several hundred gallons per minute. Establishing a reliable supply of process water in underground mines is one of the main challenges affecting mining operations globally. Underground water shortages are far too common, in most cases occurring daily, costing millions annually in lost production. When revenue generating equipment doesn’t have a reliable supply of water, operations shut down. Most mines have struggled to implement a dependable underground process water management strategy. Historically when water surges or starvation occurs, the solution is to “live with it” and fix the damage caused or apply a makeshift approach without looking at the root of the problem – the overall system design.

A traditional installation is gravity fed and allows water to flow through several PRV stations on its way down the mine ramp or shaft, known as a cascade system. Most pressure reducing valves (PRVs) in use today are pressure regulating valves, which allow for the outlet pressure to be set and adjusted. The issue is that regulating PRVs often struggle with system pressure changes, sudden flow changes, and increasing water demand. This, combined with valve droop, is the root of almost all underground process water delivery issues.

To avoid costly shutdowns due to poor process water delivery, mine owners have begun to deploy a new approach to system design. This new strategy, that in part involves valves with specialized capabilities, has proven to eliminate fluctuations in water pressure and availability, eliminating costly water shortages or surge situations.

The first step is to separate the main water supply from the underground levels to create a cascading standpipe. This should incorporate ratio PRV’s in place of regulating PRV’s throughout the cascade system. Unlike regulating valves that have a calculated output pressure, ratio valves operate on a fixed ratio pressure, so there is no set pressure on the outlet side of the valve. This, in turn, mitigates the issues previously associated with valve hunting within the standpipe system. The next step is to separate the water supply to each level by employing specialized regulating valves designed to eliminate droop. By creating one system for the shaft piping and another system to supply each level, mines can effectively manage process water.

This presentation will review the challenges associated with the current design of most underground process water management systems and review a new approach to system design to alleviate the long-term challenges associated with inconsistent water supply. We will discuss system design changes, the real effect of valve droop in gravity fed systems, and the value of a high-performance underground process water system. Using actual case studies from Vale Canada's Sudbury operations, we will review operational gains realized with a new approach to process water.

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Published in CIM CONNECT 2025 Montréal

Publisher X-CD Journal

Date of Conference May 3–7, 2025