Tag Archives: Egina

Steinert ore sorting tech picks up the Beaton’s Creek gold fine print

Novo Resources says initial laboratory-scale tests using Steinert mechanical ore sorting technology indicates an upgrade of gold into significantly reduced mass is achievable at the Beaton’s Creek project in Western Australia.

The mechanical sorting tests carried out in Australia on the Beaton’s Creek bulk sample showed that nuggety gold occurring in Beaton’s Creek conglomerates is finer grained (generally sub 1 mm) than gold at Novo’s Egina and Karratha projects (generally over 1 mm), the company said. The company is also considering using ore sorting at these two projects.

Test work was conducted on a 2.8 t split of crushed (-50 mm) and screened Beaton’s Creek bulk sample material, with analyses conducted as part of this sorting test work generating a calculated head grade of 5.72 g/t Au for the bulk sample. The vast majority of gold reported to mechanically sorted concentrates in each of the three size fractions tested, with 90.2% of gold recovered in 54.5% of the mass of the +18/-50 mm fraction; 68.8% of gold recovered in 42.4% of the mass of the +6/-18 mm fraction; and 95.5% of gold recovered in 20.3% of the mass of the +2.3/-6 mm fraction.

Material finer than 2.3 mm, comprising 17% of the total mass of the bulk sample, was not tested due to excessive dust issues, the company said. “Novo believes such material is treatable by means of gravity concentration,” it added.

“Test results are considered indicative, and Novo and Steinert see additional opportunity to optimise sorting conditions and parameters that may result in further efficiencies,” the company said. “Nevertheless, these tests indicate robust potential for upgrading nuggety conglomerate gold mineralisation, and perhaps, a broader spectrum of gold mineralisation types.”

A second 2.8 t split of the same bulk sample material has been delivered to TOMRA Sorting’s mechanical sorting test facility in Castle Hill, New South Wales, where it will soon undergo similar testing using various TOMRA mechanical sorters, the company said.

Rob Humphryson, CEO and Director of Novo Resources, said: “We are highly encouraged by these initial results. We are already fully confident about the outcome of Egina mechanical sorting test work, which demonstrated excellent recoveries into very small concentrates. Our Beaton’s Creek test work is more investigative in nature owing to the finer gold grain size, so to achieve such levels of upgrade in first phase testing is remarkable.”

He added: “Test work is being developed and supervised by Novo staff specialising in mining engineering, metallurgical processing, and importantly, our geology team. This means those people engaged in exploration are fully aware of the profound impact that mechanical sorting potentially imparts on the economic viability of our prospects. Mechanical sorting test work is likely to become an integral part of future exploration and economic modelling as we hopefully progress each of our projects towards production should the economic viability and technical feasibility of the project be established.”

Novo heralds ore sorting developments as it lines up Steinert and TOMRA trials

Novo Resources Corp says it is planning mechanical sorting test work on multi-tonne samples of gold-bearing conglomerate from its Beatons Creek project (pictured) and gold-bearing gravels from its Egina project, both in Australia, with Steinert Global and TOMRA.

Mechanical sorting of small particles of gold is seen as a potentially important breakthrough for Novo and its various nuggety gold projects throughout its large land holdings across the Pilbara, the company said.

An approximate 5 t sample of Beatons Creek gold-bearing conglomerate and an a similar sized sample of Egina gold-bearing gravel have been shipped to Perth for sorting trials at Steinert Global’s test facility in December. Conglomerate from Beatons Creek is being crushed and screened, and gravel from Egina is being screened in preparation for test work.

Once mechanical sorting tests have been completed at Steinert Global, bulk test material will be shipped to TOMRA’s test facility in Sydney for testing during the March quarter of 2020, Novo said.

Novo, earlier this month, said recent tests of Steinert mechanical sorting equipment had demonstrated recovery of fine gold nuggets as small as 0.4 mm, which was a significant step toward a potentially cost-effective “dry and chemical free” means of gold recovery.

The test work is designed to assess the veracity of recent advances in scanning and sorting capabilities of both companies, while determining – on Egina material, at least – the gold recovery capabilities of this technology as a means of primary separation; the applicability of mechanical sorting as a tool to support field exploration activities; and which model of mechanical sorter is preferred for deployment for field trials.

“Owing to recent rapid advancements in mechanical sorting technology, Novo has conceptualised a potentially viable alternative ‘dry’ processing pathway for Beatons Creek,” it said.

While testing is required to better assess sorter manufacturer claims that fine gold particles can be detected and sorted, according to Novo, the company said it sees considerable merit in this ‘dry’ processing model for the following reasons:

  • Potential to significantly reduce capital and operating costs compared to conventional ‘wet’ processing schemes;
  • Potential to reduce construction timeframe compared to conventional ‘wet’ processing;
  • ‘Dry’ processing schemes might be amenable to modular design suited to cost-effective mobilisation and relocation;
  • Negates or minimises use of water and chemicals; and
  • ‘Dry’ processing could help unlock Novo’s other assets in the East Pilbara region.

Successful mechanical sorter trials of Beatons Creek material are anticipated to lead to a larger metallurgical test work program to fully assess means of crushing, screening and sorting to be incorporated to a process flowsheet, the company said, adding that it foresees using proven technologies given there is a spectrum of commercially available equipment for dry crushing, grinding and screening.

Rob Humphryson, CEO and director of Novo Resources Corp, said: “The pace of development of mechanical sorting technology continues to astound us. We are fortunate that our nuggety gold deposits appear to lend themselves to ‘dry’ processing pathways involving mechanical sorters, technology that may generate favourable economic and environmental outcomes.

“Considering we can readily access outcropping gold mineralisation on all of our properties, we have a unique opportunity to quickly collect bulk samples for testing mechanical sorting technology on a meaningful scale.”

Novo looks to scrap metal industry for Egina gold nugget separation options

Novo Resources says it has completed encouraging processing trials on gravels extracted from its joint venture Egina gold project, in the Pilbara of Western Australia, at Steinert’s testing facility in Cologne, Germany.

Phase one of the company’s joint venture with Sumitomo Corp at the Egina gold project centres around gaining a better understanding of geology (grade, continuity, controls, gold particle size distribution, gold location within gravels, gold genesis, etc.) but also involves high level desktop studies and trials to develop potential future processing and mining methodologies.

Preliminary tests of eddy current separator (ECS) technology indicate promising potential to directly extract gold nuggets from gravel, the company said. This is one of several dry processing methodologies being considered by Novo for gold recovery at the project.

Tests conducted on a spectrum of nugget sizes ranging from 1-10 mm demonstrated consistently high gold nugget recovery via ECS technology. Nuggets that underwent testing were recently extracted from gravels at Egina, the company said.

ECSs are predominantly used to recover select metals in the scrap metal industry. Material is fed onto a conveyor, the head pulley of which contains an adjustable high-powered magnet spinning at very high rotation rates, 4,000 rpm in Novo’s tests, independent of the speed of the conveyor, Novo said. This spinning magnet induces an alternating magnetic field that differentially repels non-magnetic metals such as gold.

This magnetic repulsion causes gold nuggets to lift, or fling, off the end of the conveyor belt where they can be separated from waste material by a steel plate. These trials were designed to establish whether Egina gold nuggets react sufficiently to reliably be separated from waste material.

Novo said: “Gold at Egina predominantly occurs as free nuggets of which most are above 1 mm in size. This presents opportunity to explore innovative technologies, some used commercially in other applications such as ECS technology, to assess their efficacy for use at the Egina gold project.”

In addition to ECS technology, Novo conducted initial testing of Steinert mechanical sorting technology to detect small gold nuggets utilising an Argos EM electro-magnetic sensor, it said. Fine gold nuggets, around 1 mm, were consistently and readily detected indicating potential for direct mechanical sorting of gold nuggets, Novo said.

As a result, a combination of mechanical sorting and ECS technology is also being considered as a potentially viable means of dry processing at Egina, the company said.

Rob Humphryson, CEO and Director of Novo, said: “We are very encouraged by these initial laboratory test results utilising ECS technology. Our mantra when testing new technology and its application to our projects is to ‘test quickly and test cheaply’, and we now have in hand sufficient encouragement from these tests to consider ECS technology highly prospective for application in the field.”

The company said this preliminary testing shows ECS technology can play an important role at Egina, with potential application as a processing solution or an exploration tool, or both. “This technology generates significant inherent advantages: it requires no water, no chemicals, is of low capital cost and is readily mobile. It can also be employed along with other technologies and is scalable,” the company said.

Novo thinks field tests are warranted at larger scale to better understand recovery efficiencies, operating costs and throughput rates and the Company plans further work with Steinert to study schemes in which ECS machines, or ECS machines in combination with mechanical sorting technology, can achieve efficient recovery of gold nuggets at Egina.

The company concluded: “As Novo learns more about gold size particle and mass distribution of gold in Egina gravels, the company can then begin to estimate gold recovery.”