Above Image Credit: McLanahan.
This was originally published online by Australian Mining on 6th November 2019.
Mining companies generate extra profitability through better tailings management as it reduces the probability of dam failures and avoids remediation costs. Australian Mining writes.
The management of tailings storage facilities (TSFs) has been a topical issue in the mining industry this year, with the sector being thrust into the spotlight following a number of tailings related tragedies.
Companies, both big and small, are increasingly being held accountable through regulation to operate in a manner that is aligned with community and legal expectations.
Earlier this year, mining companies were asked to give greater disclosure of details relating to their TSFs.
This included members of the International Council on Mining and Metals (ICMM). Of the 26 member companies of the ICMM, 95 per cent now publish information on their TSFs on their websites. This includes BHP, Anglo American and Glencore.
This focus was magnified in late September when the Minerals Council Australia (MCA) developed the Australian Mining Tailings Communique alongside its member companies.
The communique, which focusses on demonstrating global leadership and best practice in governance, information sharing and technical expertise in tailings storage management, solidified the industry focus on preventing a repeat of past tailings errors.
This initiative was applauded by McLanahan, which has increasingly noted mining companies willing to invest additional funds in order to ensure TSFs are operating in a safe and sustainable way.
It represents a shift in sentiment, as the sector comes to terms with the long-term value of improved tailings management, according to regional manager Asia Pacific at McLanahan, Richard Williams.
“Almost all mining operations will have a tailings dam of some description, with the density of material discharged reflecting the size of the tailings dam,” Williams says.
“All tailings storage needs to be checked by local authorities and in Australia. Companies have to pay a deposit to local governments according to the size of the facility. That deposit is only returned once its closed so there is financial incentive to minimise the size of local facilities.”
Indeed, tailing management is a large and highly complicated business involving large-scale research and allocation of resources.
Extensive studies on geochemistry is required to identify a suitable location, mining engineers and rock mechanic specialists are required to prepare TSFs, geotechnical consultants will define and plan the deposition of material and process engineers design and provide equipment appropriate to the deposition plan.
It is a mammoth task, however; the dilemma of weighing up the benefits of forking out excess money to ensure the safety of TSFs compared with the consequences of failing to do so, is now a no brainer.
“Historically, there has been one or two significant dam failures per year,” Williams explains. With technology available to effectively eliminate these, this is now considered unacceptable.
For the global mining community, the response has been accelerated by public opinion driving legislation.
A tangible example of this has been the proposed ban on an upstream dam raising construction methodology in Brazil.
This ban, which comes into effect in 2021, has resulted in mining companies engaging equipment vendors such as McLanahan for assistance in preparing alternative tailings handling initiatives.
A number of years ago, McLanahan was offered the opportunity to participate in a project to assess the feasibility of initiating dry stack tailings for a key site.
The project involved working with site operations personnel and a mining process consultancy, to undertake tailings slurry testing in order to form an understanding of the requirements to implement dry stack tailings.
This could then be evaluated against the option of increasing the size of the TSF to manage larger volumes of unthickened tailings.
After conducting settling and filtration testing, the client chose to proceed with investing in a 1/10th scale pilot plant for operation.
Its existence would allow slurry to be de-watered, separating the liquid from the solids through gravitational separation, where differences in densities drive the separation.
This would subsequently allow tailings to be filtered, eliminating the risk of dam failure while also adding existing dam storage.
So successful was the pilot plant, McLanahan was awarded a contract for the supply of two 38-metre diameter high rate thickeners constructed from stainless steel.
For Williams, the significant investment epitomised the renewed focus of mining companies on tailings facilities.
“We wish to give recognition to these companies who have accepted that while it costs more money to manage tailings better, it’s a more sustainable way to run a business while also meeting community expectations,” Williams says.
The manufacturing phase of the 38-metre diameter thickeners are complete. Engineers at McLanahan are working closely with site to ensure a smooth transition to commissioning and commencement of operation in 2020.
In the context of an industry that is facing increased scrutiny from the community and regulators alike, the project represents a focus on better management practices and safety, a sentiment that is becoming pervasive throughout the mining industry.
For McLanahan, the Australian mining industry’s interest in getting on top of tailings management has been having a direct effect on business.
Given it has engineering expertise and a presence in the Australian market, McLanahan is increasingly being turned to as companies capitalise on the local suppliers and low-cost country options it provides.
McLanahan’s close proximity to its clients ensures close contact throughout the project, including weekly meetings and monthly reports.
This type of relationship and the benefits that stem from tailings management has McLanahan excited on what’s to come, as the sector enters into a new phase of optimising tailings safety for the benefit of the company and wider community.