As the mining industry works to meet evolving sustainability goals, water wastage in the pursuit of dust suppression can no longer be allowed.
Dust is a tricky beast on a mine site. It can coat and clog equipment, cause harm to the environment and wildlife, and impact the quality of air, water and soil.
But perhaps the most pressing effect of excessive dust on a mine site is its impact on workers, and not just in terms of causing sneezing fits and gritty, irritated eyes. Dust can have significant impacts on lung health that last far beyond the end of a shift.
Safe Work Australia has set out a range of occupational exposure limits (OEL) for the various kinds of dust found on a mine site. These OELs are usually expressed in milligrams of substance per cubic metre of air (mg/m3).
The OEL for respirable dust on Australian mine site to which a worker is exposed over an eight-hour shift should not exceed 1.5mg/m3. For respirable crystalline silica, the leading cause of silicosis, the OEL is 0.05mg/m3 over eight hours.
These limits are designed to protect workers from the effects of excessive dust, in turn requiring mining companies to take steps to keep their workforce safe.
Dust is often seen as part and parcel of working in an environment that, by nature, involves disturbing the earth. But this doesn’t have to be the case.
Modern mines work diligently to employ dust-suppression measures, the most common of which is through the use of trucks designed to spray water and other chemicals that suppress dust at the source, and with spray systems on conveyors tracking dusty materials.
This highly effective method is used on most mine site across Australia and around the world. But there’s a catch: the very dust trucks and spray systems work to suppress can clog traditional water valves that control the spray of roads and conveyors.
When this happens, the valves are often unable to shut off, wasting massive amounts of water before the issue is noticed, let alone addressed.
With mining companies more conscious than ever of reducing their environmental impact, water conservation is one of the most significant ways operators can meet their sustainability goals.
A 2011 research paper from CSIRO, ‘Water in mining and industry’, found that water use efficiency “improved greatly” in the previous 20 years, but warned an incoming boom in the extraction and processing of water-intensive minerals like iron ore would see usage skyrocket.
“As the world’s population grows, migrates towards cities and improves in standard of living, the demand for Australian minerals and metals will increase,” the report stated.
That boom is starting to come to fruition, particularly in Western Australia, where mining majors have invested significantly in green steel processing infrastructure and supply chains.
With water consumption on the rise and net-zero targets approaching, mining companies are no longer able to afford water lost to faulty equipment, especially tiny valves that should reasonably be expected to continue performing longer than a few weeks.
It’s an issue fluid control systems expert Bürkert has been combating for years.
Bürkert has a specified fit-for-purpose solenoid valve that can be implemented in any mining application. This is the 5282, is a servo-assisted diaphragm unit that requires minimum differential pressure to function.
Bürkert Australia sales manager Dave Booysen said the valve is ideal for water trucks and spray systems because, unlike alternatives, it reliably closes when automatically switched off.
“Because of the potential dirty water used for dust suppression, most standard valves get blocked more often than not,” Booysen told Mining.
“When they get blocked they get stuck in ‘open’ mode, which means there is no shut off and they will continue to pass water until a worker sees the issue and replaces or conducts maintenance on it. This could be days or weeks, depending on where the valve is positioned.”
With the demands of modern mine sites never-ending, and operators working diligently to meet a new order of sustainability metrics, inefficiencies like excessively wasted water can no longer be tolerated.
Compounded with the risk to workers and the environment from ineffectually sprayed dust, the issue quickly becomes a serious problem for which mines need a solution.
Booysen said Bürkert doesn’t take chances when it comes to the environment and worker health. He believes the 5282 valve can be summed up with a single word.
“Reliability,” he said. “The 5282 doesn’t block up and therefore controls water waste issues, giving peace of mind to the mine site manager.
“These valves have been used on mine sites across the globe for decades. The reason? They don’t fail.
“Water wastage is a huge issue for mine sites, so if Bürkert can offer a valve that will control and stop wastage for long periods without failing, that’s the valve they should have on site.”
