GHD is helping miners adopt best practices when it comes to managing tailings dams.
As jurisdictions like Australia shift to greener policies for governing industrial activity, miners must navigate a shifting landscape of liability and social license.
Few know this better than GHD, a multi-disciplinary engineering, environmental and diverse professional services group with a long history of delivering mine waste management services, from concept design through to closure and repurposing.
GHD technical director – tailings and mine rehabilitation Rob Longey spoke to Australian Mining about the adoption of best practices and emerging trends.
“Unfortunately, the global mining industry experiences around two tailings dam failures each year, and some of these have significant and unacceptable impacts on the environment and downstream communities,” Longey said.
“Australia has seen a lower failure rate, which is likely due to our drier climate and flatter terrain, resulting in lower dam heights and fewer issues managing excess water.
“Industry is working hard to eliminate these failures, trying to steer the thinking away from treating tailings dams as an operating cost, giving these large and critical assets the attention they deserve.
“Tailings dams have a design expectation of 1000 years. These are structures that are going to be around in perpetuity. So it’s not something that you take lightly as a consultant or mine owner.”
Longey said that good tailings management starts with looking ahead.
“GHD’s approach to tailings management is to take a holistic view of the site we’re working with, starting with understanding the mine waste production volumes, geochemical and geotechnical characteristics, engaging with stakeholders and developing the site’s closure plan,” he said. “Once you have developed a design for what a site should look like once it’s closed and rehabilitated to safe and stable final landform, you can work backwards from there.
“Depending on the closure plan, we design a facility based on that endpoint. For instance, if you wanted to end up with a stable facility which could potentially host a trafficable surface for a renewable energy solar farm, we may adopt a technology like filtered tailings and dry stacking.
“GHD is as concerned with decreasing the footprint of mine waste onsite as it is in putting unavoidable waste to its best use.
“We have done a number of projects where we integrate two mine waste facilities into one, such as integrating waste rock dumps downstream of the tailings dam or co-disposing tailings and waste rock for geotechnical and environmental benefits. The end result is a suitably stable dam where the risk of failure is nearly inconceivable.”
GHD not only helps build mine waste management projects from the ground up, but it also has a hand in revitalising existing facilities.
“Another trend we’re seeing is an improved focus on sustainability, with owners investigating ways to maximise value from waste. Some find they possess potentially valuable secondary critical minerals within their tailings facilities, that can be reprocessed,” Longey said.
“Some of these legacy tailings sites go back 100 years to a time when processing wasn’t as efficient and operations didn’t achieve full modern recovery of the primary mineral they were mining, or secondary minerals were not recognised or valued like they are now.
“Reprocessing tailings presents a great opportunity to modernise older facilities that might carry residual risks, like stability or seepage, or proximity to a community. In some cases we’re able to recover the tailings, reprocess them and relocate them somewhere like a disused mine void, or design a new modern facility to contain them.”
GHD works with miners throughout all stages of a project’s lifecycle.
“Good tailings management is about continual improvement through a multi-disciplinary and holistic view aimed at facility risk reduction and maximising beneficial uses of mine waste,” Longey said. “We work with site owners via a staged approach across a facility’s lifecycle, changing the design where needed to suit the changing mine life.”
Nothing captures the ethos of GHD’s ongoing commitment to clients like InsightVision, the company’s integrated digital monitoring platform for tailings and water dam assets.
Through automation and visualisation, site operators and stakeholders can monitor the vital elements of their assets, with real-time alerts from a range of instruments like GPS monitoring and piezometers.
InsightVision helps manage some of the challenges of these long-life assets, reassuring asset owners and operators.
“Many of these facilities have been around for decades. Over that time, different owners and consultants have all had a part in developing the facility, and sometimes you’ll find records are spread all over the place and in many different formats,” Longey said.
“InsightVision is able to bring all of that data into one place making for a powerful asset and knowledge management solution, which can be scaled to integrate a tailings facility digital twin where required. Visualisation and live performance monitoring data become vital for critical decision-making when and where you need it.”
Digital tools like InsightVision give sites access to essential data at a time where mines are under increasing pressure to responsibly manage mine waste.
Through a holistic approach to tailings management, GHD is helping mine sites navigate a shifting landscape.
GHD is a proud Austmine member. With more than 650 members nationally, Austmine is the leading industry body for the Australian METS sector. The not-for-profit organisation exists to promote the global advancement of technology and innovation in mining.
This feature appeared in the November 2023 issue of Australian Mining.