Tag Archives: Ben Wraith

CEEC heralds latest eco-efficient comminution medal winners

The Coalition for Eco Efficient Comminution (CEEC) has announced the recipients of its 2021 CEEC Medal, which recognises outstanding published research and field work that contributes to making mineral processing more eco-efficient.

For the past decade the global not-for-profit organisation has been championing greater sustainability in mining, with a strong focus on communicating knowledge, technology and approaches that reduce energy usage in the high-intensity breaking, crushing and grinding processes.

CEEC Chair, Mike Battersby, said the 2021 CEEC Medal award received 14 high-quality submissions from researchers, operators and suppliers around the world, with entries judged by a Medal Evaluation Panel of four CEEC Directors.

“CEEC congratulates each of the award recipients for their outstanding work,” he said. “Their contributions have the potential to reduce environmental impact and unlock hidden value for shareholders, not just in their own operations, but industry-wide.”

The award recipients are:

  • 2021 CEEC Medal – Technical Research
    Marcos Bueno, Janne Torvela, Rajiv Chandramohan, Tábatha Chávez Matus, Toni Liedes and Malcolm Powell for their paper titled ‘The Double Wheel Breakage Test’. This was published in Minerals Engineering, Volume 168, July 2021.

The authors collaborated from across the world, comprising Finland’s Marcos Bueno, Geopyörä and the University of Oulu’s Janne Torvela and Toni Liedes, Intelligent Machines and Systems, and Tábatha Chávez Matus, Oulu Mining School; Rajiv Chandramohan from Ausenco, Canada; and Malcolm Powell, Julius Kruttschnitt Mineral Research Centre, The University of Queensland, Australia.

The winning paper shares the development of a prototype breakage testing device, Geopyörä, and shows breakage calibration results that indicate its potential to improve geometallurgical ore testing.

Medal Evaluation Panel Spokesperson and CEEC Director, Greg Lane, said the paper proposes a “genuinely better way to do something we already do”.

“This paper is a credit to the authors because it presents an opportunity to cost effectively increase our understanding of the ore breakage characteristics across an ore body and change the way we design plants,” he said.

“In presenting a detailed and complete description of a new testing device, this research offers huge potential to increase the scale of testing and number of comminution tests conducted for projects. This should allow for improved design outcomes, a reduction in project risk and better throughput (revenue) forecasting.”

  • 2021 CEEC Medal – Operations
    Ben Wraith, Justin Resta and Johan Welmans from Bluestone Mines Tasmania Joint Venture, Australia for their paper ‘Recent improvements in ore sorting at the Renison Tin Concentrator – target 1 Mt/a’. This was presented at the AusIMM Mill Operators’ Conference in Brisbane, Australia in June 2021.

Renison is the largest tin producer in Australia, and the paper documents how the site overcame challenging conditions and increased processing rates by upgrading its ore through X-ray Transmission (XRT) ore sorting and other mine to mill and geometallurgy practices.

Lane said the well written paper provided a valuable insight into the application of ore sorting in an operating plant, describing the reason for installation, the issues, and the cost impacts.

“The efficiency gains from coarse ore rejection prior to fine grinding are significant,” he said. “This insightful publication documents Renison’s experience with ore sorting and shares the value that coarse ore rejection added to the business.”

The CEEC Medal Evaluation Panel also awarded two High Commendations:

  • 2021 CEEC Medal High Commendation – Technical Research
    ‘SAG mill energy and wear insights derived from measuring inside the Mill’, authored by Dr Paul Shelley and Eugene Davies from Molycop, Global; Jacques Olivier, Western Australian School of Mines, Curtin University; and Mark Atta Danso, Westgold Resources, Australia. This paper was presented at the online Comminution ’21 conference.

It was the second year running that Dr Shelley’s research on SAG mill optimisation has received a High Commendation in this category. The judges noted: “It is good to see work progressing on understanding the efficiency gains that can be achieved by understanding what happens inside a mill.

“By getting real measurements from the heart of the breakage process, the paper shows how researchers, operators and suppliers can systematically investigate methods and materials to improve milling efficiency.”

  • 2021 CEEC Medal High Commendation – Operations
    ‘Throughput improvements at the Capstone Pinto Valley Operation’, a video presentation delivered at the online Comminution ‘21 conference.

The work was authored by Umut Erol and Curtis Wettstein from Capstone Mining Corporation’s Pinto Valley copper mine in Arizona, USA, and Adrian Dance, SRK Consulting, Canada.

The judging panel said the well-presented, clear and concise presentation provided evidence of how increased fragmentation affected project efficiency and operating costs.

“The work outlines how projects can make material value improvements through diligent and well-planned work focused on optimising comminution efficiency to improve plant capacity and reduce operating costs,” the judges said.

Battersby said the CEEC Medal, now in its 10th year, would not be possible without the support of CEEC’s industry sponsors who help fund the organisation’s work in accelerating more eco-efficient mineral processing.

“Special thanks to our valued sponsors and to everyone who nominated for the award,” he said. “Abstracts from the successful papers can be viewed on the CEEC website, along with other freely available resources that catalyse industry uptake of more efficient comminution practices.”

He also paid tribute to CEEC Director, Zeljka Pokrajcic, for her stellar work in chairing the CEEC Medal Evaluation Panel for the past 10 years, before handing over the reins to Greg Lane.

Nominations for the 2022 CEEC Medal are now open, with submissions closing on 31 October 2022. Details on how to apply can be found here

TOMRA Mining’s ore sorting solution helps Renison tin mine do ‘more with less’

TOMRA Mining and its X-ray Transmission (XRT) technology has, the company says, provided an effective solution for the extreme conditions at the Bluestone Mines Tasmania JV (BMTJV) Renison tin mine in Tasmania, Australia, with sensor-based ore sorting solution unlocking significant value and delivering environmental benefits.

The Renison mine is 50% owned by Metals X through the BMTJV, and is the only major tin mine in production in Australia with a mining rate of close to 1 Mt/y, according to TOMRA. While slated capacity is 1 Mt/y, the concentrator is restricted to 750,000 t/y.

The mine’s extreme humidity and highly acidic processing water (pH around 4.5) create unique challenges for the sorting process, the equipment and waste management, according to TOMRA.

A complex flowsheet

The underground mine operates a primary crushing system before the material is transported to the surface through a shaft. Once there, it enters the pre-concentration plant, where it undergoes a three-stage crushing, screening and cleaning process. The particles are split into two fractions – 10-25 mm and 25-60 mm – which are fed into two TOMRA XRT sorters. The output consists of two streams: the product, which is transferred to the wet plant, and the waste, which is fed into a TOMRA EM sorter to separate acid-forming sulphides from this waste stream.

In the wet plant, the product goes through primary grinding followed by bulk sulphide flotation. The tailings are processed downstream to concentrate the cassiterite tin mineral through gravity concentration; gravity tails are further treated via desliming and tin flotation. The combined concentrates are fed to a leaching circuit to remove carbonate minerals. After a final wash stage, the concentrate is de-watered and dispatched.

BMTJV approached TOMRA to address two key requirements at the plant. The first was the need to upgrade the tin feed to the plant, as Ben Wraith, Principal Project Metallurgist at BMTJV (pictured below), explained: “The Renison tin operation wanted to achieve economies of scale, putting more tonnes through the front end of the plant without upgrading the back end downstream – we wanted to do more with less.”

The second requirement was to address the environmental issue of removing acid-forming sulphides from the waste.

Following site visits and extensive discussions with BMTJV’s teams, TOMRA proposed a solution that addressed the tin feed quality with two COM Tertiary XRT 1200 sorters and the waste issue with a COM Tertiary EM 1200 sorter. A team from BMTJV visited the TOMRA Test Center in Sydney, Australia, where they observed what the XRT sorter operating at capacity is capable of.

Gavin Rech, Technical Manager at TOMRA, said: “Our XRT stands out for the high spatial and density resolution and its ability to do contrast sorting, identifying fine high-density tin inclusions in the ore with an accuracy that has no equal on the market. On top of that, it can separate it from the acid-forming sulphides, so that we have the ability of pulling the tin into the first product and sending the rest to the EM sorter.”

Gavin Rech, Technical Manager at TOMRA

The two COM Tertiary XRT 1200 sorters went into operation in 2018. Initially, BMTJV’s strategy focused on low reject grades, devoting less focus to achieving the mass reject rate and overall process plant throughput. However, the specific conditions at the Renison mine affected the results achieved. The large variance in run of mine (ROM) particle size distribution resulted in insufficient stability in the feed to the circuit. In addition, the extremely wet conditions in west Tasmania and consequent high ambient moisture content, combined with the high moisture of the ore delivered from underground, further affected the sorting process.

In 2019, a new investigation was conducted into the ore sorting performance and led to a change of direction, where the operation shifted away from targeting low reject grades, towards sorting as aggressively as possible, according to Wraith, moving from a “tin recovery-based” operating strategy to a “mass reduction” one.

“We are getting 20-25% mass reduction, so 75-80% of the materials are going into the wet plant, and we are still achieving 97-98% tin recovery overall across the crushing circuit,” he said. “Pre-concentration didn’t materially impact overall recovery because the tin in the material that is rejected as waste is extremely fine grained and a proportion is associated with sulphides, so it wouldn’t have been fully recovered in the downstream wet plant and would have been lost to tailings.”

This approach, he said, is best for Bluestone’s application as it provides the ability to process 15-20% more tin units without having to upgrade the downstream concentrator.

Wraith added: “Operating the sorting circuit has slightly increased our overall processing cost, but this is more than offset by the large increase in ROM throughput by 15-20% and, thus, tin production, so the unit cost per tonne of tin produced is reduced by almost 10%. We’ve broken multiple production records in the last year in tin units, and this gives us confidence in what we can achieve because the machine performs over and over again if you treat it right and if you prepare your feed correctly.”

TOMRA XRT success leads to upgrade decision

In view of the results achieved with the two TOMRA XRT sorters, BMTJV decided to upgrade the ore sorting circuit with two new, recently launched XRT models with stainless steel internal parts and advanced features such as the TOMRA ACT user interface and the TOMRA Insight cloud-based platform, according to TOMRA.

“The decision to buy new machines was easy,” Wraith said. “The stainless steel will assist prolonging the TOMRA sorter’s life by protecting the unit from our high-moisture and corrosive environment. The more ergonomic design will help our maintenance teams, which is particularly important for machinery operating in these harsh conditions.”

Wraith said the use of TOMRA Insight, the ore sorting company’s subscription-based service that relays and analyses machine data, will “enhance everybody’s understanding and experience of the machines”.

He added: “It will be more of an analytical platform for our metallurgy and maintenance staff, providing ample opportunity to gain valuable information that can be analysed and optimised over time. The one feature I am personally interested in is the particle size monitoring through the machines, which will enhance our overall circuit performance because we have an integrated circuit with the crushing and screening plant. Feed preparation is key to maintain a consistent performance – knowing how well you’re preparing your feed in a live fashion can only end up with a better result.”

TOMRA will also be able to log into the machine and check the daily reports generated by TOMRA Insight, so its technical teams will be prepared ahead of site visits for maintenance or optimisation.

Wraith concluded: “TOMRA has been working with the site maintenance team to tailor solutions to our operating environment, which has been invaluable. TOMRA supported me through site visits, which included equipment inspections, site-based training of our personnel, and an openness to continually improving the technology and finetune it to our site-specific requirements. They assisted the site with troubleshooting, optimisation, discussing the nuts and bolts of the issues as they arose, and finding a solution that works.”