Tag Archives: Cooperative Research Centre for Optimising Resource Extraction

CRC ORE simplifies complexity for value

Bulk handling, Comminution of minerals, IoT, Mineral processing, Mining events, Mining services, Precious metals, , , , , , , , , , , , , , , , ,

“There are a lot more variables to bulk ore sorting than just the technology,” Jon Rutter says.

The Principal Geologist of the Cooperative Research Centre for Optimising Resource Extraction (CRC ORE), Rutter knows his stuff. He has worked underground in both narrow-vein and mass-mining operations, as well as at large scale open-pit mines; in the base and precious metal arena.

During a presentation at International Mining Events’ IPCC Virtual event in early-February, he shared a slice of this knowledge while reviewing a recent installation project CRC ORE had been involved in at a platinum group element (PGE) operation.

“The intrinsic value of bulk ore sorting comes from the delivered heterogeneity,” Rutter said. “We have got to be able to sense and divert a higher-value pod of material versus an adjacent pod of lower-grade material on a conveyor.

“You essentially want to put more material into the mill that adds value – and not what destroys value.”

Looking at the wider bulk sorting opportunity in mining, Rutter explained the sensor diversion units (SDU) in bulk ore sorting were smaller than what the mine itself can typically offer in the form of a selective mining unit (SMU), which may be comprised of a dig block totalling around 15,000 t.

A truck offers a 100-300 t opportunity, while a shovel typically comes with a 50-100 t opportunity.

Even with a modest conveyor running at a 2,000 t/h rate, an on-board sensor (eg PGNAA or PFTNA) running at a 30 second integration time (the time to analyse one grade) would provide an SDU of 16.7 t. A sensor with lower integration time (eg XRF at 10 seconds) comes in at 5.6 t.

The ability to provide analysis down to this level has enticed several major companies into testing bulk ore sorting solutions.

Anglo American has trialled bulk ore sorting solutions at copper and platinum group metal mines, while BHP recently engaged CRC ORE to examine deployment of cutting-edge preconcentration techniques under its Grade Engineering® platform at the Olympic Dam mine, in South Australia.

The SDU with bulk sorting may be that much smaller than the SMU of a typical mine plan, but lab-level precision is not required for these solutions to work, according to Rutter.

“What I need is the ability to measure the metal content adequately,” he said. “When I say adequate, this incorporates the entire error bar of the system. That system includes the inherent geology, the mineralisation style and heterogeneity. We also need to consider the precision, accuracy and integration time – which is the technology constraint; but we also need to include the weightometers, the flop gates, the diversion gates, as well as that entire mining and materials handling process right from the start – from blasting, loading, hauling and dumping to the plant.

“But for bulk ore sorting what I end up requiring from this combined data is usually a binary decision: am I above or below a certain threshold?”

He expands on the bulk ore sorting (BOS) assessment process: “The other way of looking at this is simply considering it as planned ore loss and dilution. If we go back into that dig block, in that 15,000 t of material, I’ve already incorporated planned ore loss and dilution decisions or parameters into that SMU decision. So, if we look at bulk ore sorting, I am just talking about those different attributes – the error bars of a BOS system – as the inputs or parameters for BOS planned ore loss and dilution – it’s now just at a smaller and more precise opportunity.”

The company took a two-phase approach to the BOS opportunity at the PGE operation in question.

The first phase involved carrying out heterogeneity analysis of the orebody; correlation analysis of PGEs to base metals; selection of sensor technologies (XRF and PGNAA were selected in this case), design, layout and equipment selection for the bulk ore sorting plant; natural deportment analysis of the orebody; development of a preliminary business case; the ore type selection and sampling strategy; and project planning and management.

CRC ORE and the company in question settled on a solution where a Caterpillar 992 wheel loader dropped material off to a system using a combination of grizzly, feeder, sizer, conveyors, diverter, stackers and associated equipment from MMD, used in conjunction with an ore sensing system equipped with both PGNAA and XRF sensors to continuously measure the elemental composition. The PGNAA sensor provided a “penetrative” analysis calculation whereas XRF provided a “surface” sensing calculation, Rutter explained.

An incline conveyor ahead of the diverter gate and the accept/reject stream provided the 30 second integration time the PGNAA analyser required.

Phase two of the project involved online and offline (pre-install) work; sensor calibration; proving the technology; and proving the technology can drive physical separation.

Rutter said the completion of static calibration of the sensors saw the PGNAA sensor 20-30% calibrated, and the XRF sensor 70-80% calibrated.

This outcome harked back to Rutter’s assertion that “bulk ore sorting implementation is not a plug and play opportunity”.

A dynamic calibration in online mode completed under normal conditions was required to get the PGNAA sensor up to speed. This process, meanwhile, solidified the operation of the XRF sensor.

While the two sensors were calibrated in different ways, Rutter showed data that confirmed both were in unison when it came to reading the ore/waste that came through the conveyor (see right-hand graph below).

“The two sensors are independent of each other and fundamentally very different, but they can work well together, or separately,” he said.

CRC ORE was able to prove the technology by running the same sample through the circuit a number of times, as Rutter explained: “We fed 15-20 t of run of mine material into the hopper and repeated the process 15 times, putting the same 15-20 t sample through the system. We could then start to determine the precision and accuracy of the sensors and the system.”

For further verification, the sample was crushed, sub sampled and assayed.

“We wanted a binary response to ore and waste to build confidence,” Rutter added.

Phase three involved the ramp up to production scale, going from, say, 500 t/h to 1,000 t/h; carrying out validation by campaign; and finally integrating with the operation.

There were several lessons all mining companies – and bulk sorting vendors – should keep in mind from such a project, Rutter said.

Operations need to assess the impact of mixing across the entire materials and mining handling process as soon as possible, for one.

“The earlier we can put this data into the system, the better,” Rutter said. “Without a heterogeneity signature, we cannot implement bulk ore sorting.”

He also stressed the importance of timely feedback. Sensor calibration, a secondary crushing/sampling plant and assaying were all required to build confidence in the solution.

Rutter added: “The proper calibration of sensors does require a considerable and ongoing effort…but that is no different from any other process plant or equipment.”

Operators also need to be wary of where they set these solutions up in mines, recognising this heterogeneity dynamic.

“Bulk ore sorting is quite unlikely to be universally suited to the entire deposit,” Rutter said. “The analogue for this is a flotation plant; there are ore types in the mine where you achieve better performance in the flotation plant and others where you get worse performance.”

CRC ORE’s Kal Hub integrated into Curtin University’s WA School of Mines

Careers in mining, Mining services, , , , , , , , , , , , ,

The Kalgoorlie-Boulder Mining Innovation Hub, an initiative of the Cooperative Research Centre for Optimising Resource Extraction (CRC ORE), has, this week, transitioned to be part of Curtin University’s Western Australian School of Mines (WASM).

The Kalgoorlie-Boulder Mining Innovation Hub has been operating out of the Chamber of Mines and Energy (CME) office in Kalgoorlie, Western Australia, since 2018. It was established in the renowned Goldfields mining community thanks to a partnership between CRC ORE, Curtin University, the Minerals Research Institute of Western Australia, the City of Kalgoorlie-Boulder and CME.

CRC ORE Chief Operating Officer, Dr Luke Keeney, said he was pleased that the Kal Hub has become part of WASM and will continue this collaborative innovation.

“We are proud of what has been achieved through the Kal Hub since its inception and look forward to seeing great things under its new stewardship,” Dr Keeney said. “It is an optimal outcome that Curtin University, one of our valued Research Participants and key partner in the hub to date, is ensuring the future of the Kal Hub as a centre of mining innovation for Western Australia and beyond.”

Curtin University Kalgoorlie Campus Director, Sabina Shugg, said the Kal Hub is a welcome addition to the local campus.

“The Kalgoorlie-Boulder Mining Innovation Hub is growing in stature and already has strong ties to the University, WASM and the local community,” Shugg said. “It is fitting that the Kal Hub is now operated locally to focus on innovations and solutions for the local mining industry.”

Reflecting on the hub and its achievements while operating as a node of CRC ORE, Dr Keeney said the flagship Integrated Screening and Particle Sorting project was a standout.

“This collaborative study with Australian mining companies BHP, Norton Gold Fields and Saracen on the integration of screening and particle sorting techniques is delivering benefits across the resources sector,” Dr Keeney said. “Run through the hub, this study developed a robust and scientifically rigorous framework for collecting, testing and reporting results for integrated screening and particle sorting techniques in a variety of ore domains.”

Dr Keeney said the hub creates opportunities for innovation, collaboration, employment and education.

“We’re particularly proud of being able to engage students – mining’s future brightest minds, with the hub through the vacation student program,” he said.

As part of the transition, Kal Hub Technical Adviser, Dr Laurence Dyer, now works full time for Curtin University. He divides his time between hub projects and his existing role as Curtin’s Discipline Lead for Metallurgical Engineering.

“I’m looking forward to continuing to support collaborative innovation throughout the Goldfields region and beyond,” Dr Dyer said.

Curtin University is planning several new initiatives for the Kal Hub including scaling up an existing major water management project and new partnerships with leading mining technology providers.

Kalgoorlie-Boulder Mining Innovation Hub uncovers a fraction of processing value

Base metals, Comminution of minerals, Energy minerals, Environmental, Metallurgy, Mineral processing, Mining equipment, Mining services, Precious metals, Sustainable mining, , , , , , , , , , , , , ,

Extensive testing conducted by a Kalgoorlie, Western Australia-based research hub has found Western Australian Goldfields mine sites can add value to their operations by focusing on small size fractions.

In recent decades, the primary driver to maximise profitability of mining operations has been to mine and process as much material as possible to exploit economies of scale. This has led to bigger equipment, higher throughput and greater production, but not necessarily efficient use of resources.

With the concerns of declining grades, more complex orebodies, greater haulage distances, higher energy costs and water usage, any approach that can alleviate the impact of these issues is highly desirable.

The Kalgoorlie-Boulder Mining Innovation Hub recently explored use of a pre-concentration technique known as “Grade by Size Deportment”.

“This technique exploits the propensity for some ores to exhibit preferential breakage leading to concentration of minerals in specific size fractions,” it explained.

Several sites within the Goldfields region of WA showed significant potential for separation by size to provide value to their operations, according to the hub. This is particularly the case where either marginal grades are present or growing distances from face to surface, or, from mine to mill, are subject to increasing transport costs, it said.

Research and test work by the hub show that natural grade by size deportment during coarse rock breakage and screening is a key lever for generating high-value coarse separation, it said. This, in turn, can drive better productivity and returns for mine operators.

The Kal Hub, established in 2018 by the Cooperative Research Centre for Optimising Resource Extraction (CRC ORE), enables focused collaboration between researchers; mining equipment, technology and services suppliers; and mining companies to unlock value for Australian mining through technology development.

CRC ORE Chief Operating Officer, Dr Luke Keeney, said: “In a short amount of time, the hub has been able to bring together some of the most innovative people in industry and research, enabling collaborative innovation to occur.

“This collaboration is good for the Goldfields, and for the wider mining industry, as it demonstrates the benefits mine sites can experience by deploying various aspects of Grade Engineering®, including grade-by-size deportment.”

Grade Engineering is a system-based methodology developed by CRC ORE designed to reject low value material early in the extraction value chain and pre-concentrate processing plant feed. A key lever for successful Grade Engineering is grade-by-size deportment, the hub said.

The Kal Hub Technical Advisor, Dr Laurence Dyer, said the objective of the Grade-by-Size Deportment project was to undertake initial representative sample testing to determine natural deportment Response Rankings at a range of deposits in the Kalgoorlie-Boulder region.

“This project provided an introduction for industry participants to Grade Engineering and an indication of potential opportunities that grade-by-size deportment may present,” Dr Dyer said.

“A number of companies came on board and we were able to obtain diamond drill core and reverse circulation (RC) drilling samples from a variety of sites in the Goldfields to crush, screen and assay to develop a snapshot of responses to this approach.”

Samples were crushed where necessary and screened into up to six size fractions, with a finer set of screens used for the RC samples to accommodate the difference in particle size distribution.

As expected, gold sites displayed significant variation in response, while all nickel sites tested showed significant upgrade in the finer fractions of both nickel and cobalt, the hub said.

“RC samples were a compelling sample option due to their prevalence and self-preparation for screening, however there remains a question as to the legitimacy of the results they generate,” it added.

Dr Dyer said: “Gold samples produced varied data with the majority of sites producing low to moderate upgrades on average.

“The RC samples generated greater variation and often decreased in grade at the finest size fractions, likely due to particles being below liberation size, creating issues with the response ranking fit.”

The Kal Hub research also showed nickel produced far more consistent behaviour with all sites producing moderate to high responses for both nickel and cobalt. While for some samples the nickel and cobalt response rankings matched well, in others, the nickel upgraded significantly better, it said.