Tag Archives: tailings storage facility

Taseko Mines’ Gibraltar operation honoured at BC Mine Reclamation Awards

Taseko Mines’s Gibraltar copper-molybdenum operation has been awarded the prestigious Jake McDonald Annual Award for Metal Mine Reclamation from the British Columbia Technical and Research Committee on Reclamation (TRCR).

TRCR’s annual BC Mine Reclamation Awards, which recognises outstanding achievement in mine reclamation in British Columbia, was held on September 23, 2020.

The aim of Gibraltar’s reclamation research program is continual improvement by identifying and introducing leading-edge ideas within the field of environmental science in mine reclamation, it says. With this goal in mind, projects at Gibraltar include:

  • Sampling of salmon from the Fraser River in partnerships with the Xatśūll First Nations and the North Shuswap Tribal Council to provide information to local Indigenous communities regarding the safety of consuming salmon captured at traditional fishing sites;
  • Studying and using innovative technologies to determine how reclamation activities promote the development and recovery of biological communities; and
  • Supporting BCIT, SFU, and Mitacs master’s students in a trial research program to expedite the development of soil microbial crust, specifically at the tailings storage facility.

Stuart McDonald, President of Taseko, said: “The Jake McDonald Award is the top mine reclamation award in British Columbia, a province that has a large mining industry. This achievement reflects the hard work of many talented people and we are honoured to have been chosen as this year’s recipient. The award adds to our track record of achievement which includes other recognition awards for employee safety and community service.”

Russell Hallbauer, CEO and Director of Taseko, added: “Gibraltar has been operating for nearly 50 years, generating opportunity for people and economic benefit for communities in the Cariboo. The efforts of our Gibraltar employees continue to be rewarded by achievements like this high-profile award. It is gratifying to see their talent and ingenuity being recognised at the highest levels. Gibraltar is proof of mining sustainability in action.

“We would specifically like to acknowledge the local Xatśūll First Nations and the North Shuswap Tribal Council Fisheries Department for their partnership and traditional knowledge in the annual Fraser River salmon sampling program. As well as a thank you to the Xatśūll First Nations reclamation crew, whose participation has contributed to the success of Gibraltar’s reclamation program.”

Xatśūll First Nations Chief, Sheri Sellars, said: “I am proud of the work Xatśūll First Nation community members have done in partnership with Taseko-Gibraltar. The fish sampling program and the reclamation work have been award-winning successes. Our members have also benefitted from employment opportunities and educational initiatives which stem from our relationship with Gibraltar.”

Taseko, the 75% owner of Gibraltar, restarted the operation in 2004. It is the second largest open-pit copper mine in Canada and the largest employer in the Cariboo region, according to the company.

Mining network needs to align on safe tailings dam design, SRK’s Spies says

Safer tailings storage facilities (TSFs) – or tailings dams – can be achieved when mine owners, contractors and engineering consultants work closely together, says SRK Consulting’s Linda Spies.

Speaking after a recent Southern African Institute of Mining and Metallurgy (SAIMM) conference focusing on tailings dams, Spies, Senior Geotechnical Engineer at SRK Consulting, said that mining executives today required more assurance that their tailings dams are safe, with controls becoming much stricter. Greater transparency was also being demanded by other stakeholders such as investors and communities, she added.

“After several hundred lives were lost in two well-publicised tailings dam failures in Brazil, in 2015 and 2019, awareness of tailings dam risks has been raised within the mining industry and in the public eye globally,” she said. “These latest failures were especially significant insofar as senior management at the mining companies were for the first time being implicated directly with charges of manslaughter and environmental damage.”

She noted that while conferences on this topic usually involved mainly tailings dam practitioners and academics, this event had strong representation from owners; contractors, who are responsible for tailings dam construction; and consultants, who design TSFs and monitor their construction.

“This meant that the discussion was more holistic and valuable, enriched with insights from these various perspectives,” she said. “This is vital in promoting innovation, safety and environmental and social responsibility in the design, operation and closure of tailings dams.”

While the tone of the event was serious considering recent failures, there was also an optimism flowing from a showcasing of best practice in the field and how this was being successfully applied. In her own case study presentation on a lined tailings dam at a South African platinum mine (Impala’s Marula dam), Spies highlighted the complexities introduced by the liner requirement – and how good drainage design and quality assurance were an important part of the solution. (see Getting lined tailings storage facilities right below)

Among the key issues discussed at the conference was whether upstream tailings dams should be allowed – as this was one of the commonalities in the recent Brazil failures. High-level input was given in a panel discussion by senior leaders from a mining company, a law firm and an insurance firm, including technical opinions from tailings industry expert and specialist geotechnical engineer Adriaan Meintjes, a Partner and Corporate Consultant from SRK.

According to SRK Principal Hydrogeologist and Numerical Modeller, Sheila Imrie, who also presented at the event, tailings is rightly receiving considerable attention from a combined engineering and scientific perspective and will continue to do so in the future.

“The continued application of the latest technologies by the industry’s top experts is critical,” Imrie said. “Industry must also ensure that sufficiently detailed research, monitoring and numerical modelling informs the future design and current management of tailings dams.”

She presented a paper on ‘3D Seepage Modelling in Tailings Storage Facility Analysis and Design for Low Permeability Lined Basins’ with SRK Civil Engineer, Wesley Rouncivell. A key aspect of the safe operation of tailings dams into the future involves comprehensive and rigorous monitoring of these facilities on a regular and real-time basis, they said.

In another SRK presentation, GIS Specialist, Ansu Louw, and Civil Engineer, Riaan van der Colf, gave their insights on a ‘GIS-enabled, Web-based TSF Monitoring Solution’ by SRK to enhance monitoring of tailings facilities.

Getting lined tailings storage facilities right

The inclusion of a liner in a tailings dam brings many environmental benefits, but also increased complexity in design, construction and operation, Spies says.

In her presentation – ‘Design of an HDPE-lined platinum tailings facility in South Africa’ – at the SAIMM Tailings Storage Conference, in Gauteng, recently, Spies highlighted the importance of well-designed drainage systems. These are vital to drawing down the phreatic surface, reducing the seepage gradient and minimising the liquefaction potential of tailings, she said.

She also emphasised high construction standards to ensure tailings dams successfully limit seepage, and outlined a series of quality control and assurance measures.

Weir to expand tailings dewatering offering with new ‘innovative’ solution

As the Global Tailings Review prepares to issue a new industry standard in 2020, Weir Minerals has chosen now to examine the subject of dewatering tailings.

The company, already offering solutions to help dewater tailings, says it is developing an “innovative tailings dewatering solution” to allow operators to pump slurry containing an extremely high percentage of solids. It says it plans to launch the new technology in 2020.

Mike Swintak, Regional Senior Product Manager for Weir Minerals, said dewatering tailings can be a difficult process, yet, when undertaken successfully, “it can deliver significant benefits to mine operators”.

The foremost benefit of dewatering tailings is the reduction of water that needs to be transported from a process plant to a tailings storage facility (TSF).

Reduced water content means tailings slurry volume is decreased, allowing for smaller pipelines and pumping equipment to be used. This can also minimise power requirements.

Thickened tailings and paste can improve the stability of TSFs and diminish their footprint. In some instances where existing TSF capacities are limited by regulatory or other environmental considerations, thickened tailings can help to extend the life of the mine, Weir says.

“Proper containment of tailings reduces the risk to people and the environment, and when decommissioning a mine, thickened tailings facilities are easier to rehabilitate,” the company added.

To a growing extent, thickened tailings are also used for underground mine backfill. This can increase productivity and reduce mine cycle times as well as surface TSF disposal volumes. Underground mining conditions can also be improved due to decreased water and slimes handling.

Important considerations and challenges

“When tailings are not properly managed, the results can be lethal. It is vital that mine operators have a clear understanding of key risks and considerations related to this process, in particular, tailings dewatering,” Swintak said.

Every mine site is different and subject to varying environmental, regulatory, capital and operating cost constraints.

Cost is a key consideration for many operators and can adversely affect the viability of a mine site, according to Weir. Therefore, it is necessary to implement a tailings management strategy that provides both reliability and value for money.

“Environmental limitations are also a major factor when establishing a TSF,” Weir says. “In parts of the world where there is challenging topography, such as mountainous regions or other environmentally sensitive landscapes, TSFs may need to be built further away from the process plant. This can result in slurry being transported across longer distances or higher elevations. Dewatering of tailings is a viable option in these scenarios as less slurry needs to be moved, in turn reducing operational costs.”

Some operations produce highly diluted tailings that require extensive dewatering to reach the desired level of thickness. Other slurries may contain extremely fine particle solids that are also difficult to manage. Large mine sites, or those with complex orebodies, can produce many types of tailings waste slurries, which may require varying methods of treatment.

“Across this multitude of situations, the operator must determine all associated costs and assess the level of dewatering required to confirm the most suitable solution for their site,” Weir says.

“While some mines are in a position to increase the size of their TSFs, many are not, and must implement a viable dewatering process, which can involve significant capital expenditure.”

If dewatering tailings to the highest possible degree, operators also need to develop a suitable strategy for transporting the waste material. Tailings that are too thick to be pumped may need to be transported by either a conveyor system or truck.

Finally, when a mine site reaches the end of its life and moves into the decommissioning phase, TSFs must be dealt with in accordance with regulatory and legislative requirements. As many mine sites need to be rehabilitated and restored to a natural state, a key benefit of producing thickened tailings is its ability to be covered with overburden and re-planted with suitable vegetation.

Weir Minerals offering

“Weir Minerals realises dewatering tailings can be a daunting process for many operators,” it says. “In order to provide the highest level of support and service, the company has invested heavily in its tailings management capabilities. More than just a supplier, every mine site is assessed on a case by case basis to provide a complete tailings dewatering system customised to the customer’s applications and constraints.”

Swintak added: “From developing flow sheets and process requirements to supplying equipment including dewatering systems incorporating our Isodry thickeners and filters, Multiflo floating and mobile pump systems for use on tailings ponds, or GEHO positive displacement pumps capable of transporting high density slurries up to 200 km, we provide customers with peace of mind through our tailings solutions.”

A key point of difference, according to Weir, is the intensive pilot plant testing Weir Minerals can perform at the Weir Technical Centre in Australia. This facility is designed to test tailings samples from around the world to help ascertain the best way to process them in line with the customer’s requirements. Testing is conducted using thickeners/clarifiers, hydrocyclones, filters and centrifuges, as well as a comprehensive pipe loop facility for determining high density slurry pipeline design.

Weir Minerals can also conduct testing at customer mine sites to assess the viability of various tailings management strategies.

As the mining industry gains a better understanding of tailings, it is vital new and improved methods of containment and storage are developed.

“Weir Minerals believes that the dewatering of tailings has a fundamental role to play in this, and continues to push the boundaries of possibility,” it said.

GlassTerra IoT LiDAR monitoring solution being trialled at Mount Morgan mine

Queensland, Australia-based technology startup GlassTerra says it is collaborating with a global satellite connectivity company to conduct a proof of concept project to monitor a key embankment in real-time at the former-operating Mount Morgan mine.

Mount Morgan, which was a copper, gold and silver mine that operated up to 1981, is now abandoned and managed by the Queensland Government’s Department of Natural Resources, Mines and Energy.

GlassTerra has installed one of its Internet of Things LiDAR sensors at Mount Morgan to demonstrate the safety benefits of real-time tailings embankments monitoring. The collaboration will showcase the integration of this technology with GlassTerra’s geospatial platform and global satellite connectivity to achieve highly reliable real-time monitoring of tailings embankments, GlassTerra said.

GlassTerra Chief Customer Officer, Sophia Li, said the combined solution will demonstrate the ability to conduct real-time monitoring of unplanned movements of earth and other parameters, on embankments such as tailings facilities.

“Real-time monitoring of embankments enables prompt reporting, investigation and mitigation of any changes, which can enhance safety, improve the protection of our environment and advance the social performance of the mining industry,” Li said.

It also has potential applications in the 3,500 tailings storage facilities in the global mining sector. This project has already led to GlassTerra securing a contract for real-time tailings embankments monitoring in Africa, the company said.