When Concept Environmental Services was approached by a major mining company for a tailings solution that would allow it to not only store waste appropriately, but also use the product in the process at a later date, it rose to the challenge.
Prior to installing a Concept Environmental Services nickel recovery plant, this Western Australian site was sending large quantities of nickel rich fluid to a tailings storage facility during processing plant shutdowns.
In addition to throwing away valuable metal among the waste and being a loss of potential income, this was a threat to the local environment.
The mining company approached Concept Environmental Services for a solution to counter both issues, allowing it to capitalise on the nickel rich liquor being lost during the shutdown process, while safely disposing of the waste.
As Concept chief executive officer Paul Avey explains, despite some initial hurdles, the company identified a solution that not only solved the waste issue and environmental threat, but also provided benefits for the reduction of water usage.
“What the company looked at initially was building a tailings dam in an area they already had available,” Avey tells Australian Mining.
“What they found though is the groundwater was about a metre below the surface, so they would not be able to build a dam below ground level.”
After this setback, the mining company proposed constructing walls around a block of land to build a ‘turkey nest’ style of dam that way, however, this was going to be extremely invasive to the site’s operations.
“That option was going to require one truckload of soil every seven minutes for two weeks for construction, so they were going to require a lot of truck movement and it would effectively shut down the site and reduce site safety,” Avey says.
Building a tailings dam this way also requires a lengthy approvals process by the Western Australian Government and local council, meaning valuable nickel rich liquor the storage facility was not going to be commissioned before a major site shutdown.
To counter this, Concept proposed a patented pre-engineered storage solution, which included an integral lining system to prevent liquid from seeping out onto the earth and into the local environment.
“They had a look at what we were proposing and agreed that this was going to be the best solution for the company,” Avery says.
“Our pre-engineered structures sit above ground, they’re financially viable, you don’t need to dig into the ground for installation and it meant there was going to be a quicker approval turnaround.”
Concept installed the tanks in August 2019, allowing for a swift turnaround time prior to the plant having a major shutdown during November.
Although this was a very short turnaround time for installing a major upgrade to part of the site, Concept was able to get the tanks installed, approved, signed off and even in operation within this time frame.
“There was a very short lead time, but we met the customer milestones,” Avey says. “They were able to capture all of the nickel rich liquor coming out of the plant before the shutdown, rather than sending it to the tailings dam, then reprocessed it through the nickel plant.”
“Obviously it’s highly acidic liquid and full of dissolved metals, so the linings system we used was really important to get right.”
According to Avey, significant quantities of nickel rich liquor was being sent with the waste products into the tailings dam before switching to the Concept tanks.
As well as helping to recover more nickel for profit and preventing adverse materials from entering the environment, Concept Environmental Services’ solution also provides the ability for mining companies to minimise their water usage through storm water recovery.
Avey says one of the key waste management processes mining companies are starting to look at is how to reuse water, particularly in Australia where drought conditions can be common.
“We’re also capturing stormwater mining companies can use for processing,” Avey says. “So that’s reducing the load on the tailings storage facility.
“By capturing the stormwater, mining companies can use the stormwater in their ponds so they are using less town water.”
In addition to the significant environmental benefits, Concept’s tailings solutions also improve the safety of a mine site.
By putting less liquids into tailings ponds, this reduces the risk of tailings dam failures such as the Brumadhino tailings dam disaster in Brazil in 2019, which claimed hundreds of lives and destroyed local communities.
“The less liquid you put into the tailings pond, the lower the risk is of a failure,” Avey says.
Once the tailings solutions are installed, Concept Environmental Services runs preventative maintenance inspections every six months, to ensure they are operating as required.
“Once we’ve installed our storage solution, we look after our clients forever. The solutions are high quality, do the job, are quick to install and are easy to have approvals processed for by the authorities,” Avey concludes.
This article will appear in the May edition of Australian Mining.