Tag Archives: ore sorting

Imilingo after optimal XRT ore sorting process with iPlant package

Comminution of minerals, Gem stone mining, Industrial minerals, Metallurgy, Mineral processing, Mining equipment, Mining services, Mining software, , , , , , , , , , ,

X-ray Transmission (XRT) ore sorting is being rolled out across the industry, with companies mining metals and minerals from various parts of the periodic table taking advantage of its sensing capabilities.

South Africa mineral processing company, Imilingo gave an exclusive world-first preview of its latest innovations in sensor-based sorting at the Electra Mining conference in Johannesburg last year. IM caught up with Managing Director, Jaco Prinsloo, to find out more about the company’s offering.

IM: How does Imilingo’s ore sorting offering differ from others on the market?

JP: Imilingo utilises mainly XRT sorting, which is at the forefront of sorting technology in diamond and tungsten applications. Imilingo’s iPlant packages the technology in a way that optimises the efficiency of the sorting machines and provides customers the advantage of dealing with a tried and tested system versus a system made up of a combination of components that are possibly less than ideal for their application. The mobility of the plants also plays a big part in providing the client with a workable solution in African countries and abroad.

IM: Do you use ore sorters from some of the major suppliers and then integrate them into your iPlant offering?

JP: Yes, we have built a strong working relationship with TOMRA Sorting as they are at the forefront of sorting and have a proven track record. The iPlant was specifically developed to prepare material for sorting and delivering the feed material in a clean and well classified state, which increases the efficiency of the sorting process.

IM: How does this customisation result in the optimal conditions for an effective sort?

JP: Efficient material classification and fines removal is key to the sorting process and that is what we focus on when developing a plant. Factors such as operator safety and equipment reliability come standard with our bespoke plants.

IM: Why have you chosen to specialise in diamonds, coal and heavy metals?

JP: Diamond recovery is a clean and relatively simple process, which lends itself to the development of standalone modular plants that can easily be expanded based on a client’s requirements. Tungsten has a much higher specific gravity than the host rock containing it, making it a very effective sort and resulting in a very efficient upgrade of run-of-mine ore. In terms of coal, Imilingo had a test plant running in Middelburg (South Africa) that was relatively successful but not commercially viable at the time due to market constraints.

IM: Have you carried out any commercial coal installations?

JP: No, we have only run our own test plant but believe the coal market is up for the taking in terms of coal sorting. Based on the running of our test plant, we believe that there remains a great opportunity within the coal market for utilising XRT sorting.

IM: Since showcasing your offering at Electra Mining in September, what interest have you had from the mining community in terms of using your solutions?

JP: We have had many enquiries regarding our sorting and dredging solutions. The nature of mining projects is that time is required for projects to mature and convert into actual sales. We believe the main effect of the Electra show was to establish our name in the marketplace and create awareness of our offering, which has been achieved.

The upcoming IM March issue will feature an article on ore sorting

MineSense front and centre in bulk ore sorting game

Automation, Base metals, Bulk handling, Comminution of minerals, Environmental, IoT, Metallurgy, Mineral processing, Mining equipment, Mining services, Mining software, Steel and iron ore, , , , , , , , , , , , , , , , , , , , , , , , ,

Having just commercialised its bulk ore sorting technology at Teck Resources’ Highland Valley Copper (HVC) operations in British Columbia, Canada, MineSense is looking to show the wider industry just how effective this pre-concentration process can be.

IM spoke with President and CEO, Jeff More, to find out more about the company’s ShovelSense and BeltSense technologies and how the Vancouver-based startup has been able to secure investment from the likes of ABB, Caterpillar and Mitsubishi.

IM: Can you explain in a little more detail how your ShovelSense and BeltSense solutions work?

JM: The base technology for both is X-ray Fluorescence (XRF) – a technology that has been around for some time. What we have done to this existing technology, which is quite unique, is three things:

  • One, we have extended dramatically the range of XRF. Traditionally XRF would almost have to be held to the surface of a rock to get accurate measurements. The range extension allows us to work in the shovel environment where we are working across metres of volume;
  • Second is speed. Our system is extremely fast. High speed analysis is required on our conveyor belt applications, but this is even more important in the shovel, where we’re measuring dynamically; as the material is flowing into the shovel, to get a representative reading, you have to be able to take very fast readings of the material as it is moving past the sensors;
  • The third is robustness. On a shovel, you are in a nasty environment from a shock and vibration perspective. We developed a system with sensitive components – the XRF itself, as well as the computing devices around it – that can stand up to that very high shock- and vibration-type environment.

IM: The most high-profile examples of the application of your ShovelSense technology have been at copper mines (HVC, in particular); is the detection technology particularly effective in these ores? Is it being trialled elsewhere?

JM: The current sensing we have with the XRF is very effective in a certain section of the periodic table, which nicely covers the major base metals. We’re focused on copper, nickel, zinc and polymetallic versions of those three. The fourth area of focus is iron ore.

We’ve selected copper as our first focus because of the size of the market and the geography. We have done most of our work in copper, but we now also have operating systems in nickel and zinc.

On a lab scale, the technology has been very effective in iron ore, but iron ore is a very different flow sheet, so we have purposely set it as our fourth market in what we call our primary clusters.

We have five mine site customers at the moment – three copper, one zinc-lead and one nickel-polymetallic.

We were very much focused on North America and, in particular, British Columbia for our first pilots and trials as it was quite easy for us to service in our back yard. The first international market was Chile, for obvious reasons in terms of copper production, and we now have a full MineSense entity and team operating in Chile and Peru.

We’re staggering the rest of our global expansion. We’re now quite active from a business development perspective in southern Africa – South Africa, Zambia, DRC – and have activity in Australia.

We have Systems installed at two different copper mines in British Columbia, one at a very large nickel-polymetallic complex in Sudbury, Ontario, and will have a fourth system operating in Alaska. We also have two mines, but four systems, operating in Chile. By the end of Q2, we will have another three systems operating in Chile.

We did all our development work for the system at Teck’s HVC operation and we’re now completely commercial there. We officially commissioned our first system in December, the second system is being commissioned as we speak and the third and fourth will be installed and commissioned in late-March. This will completely equip their fleet.

IM: Teck has previously said the use of ShovelSense has resulted in “a net measurable increase in the amount of ore (and the associated head grade)” it has available to feed its mill at HVC. Are these results in keeping with your expectations for the technology?

JM: Yes, absolutely. We base everything on, what we call, our value model. Very early in our engagement process, we set out a detailed model that calculates the profit improvement that mine will see – we did the same for Teck HVC.

We agreed on a target at HVC and are actually exceeding that estimate. Most importantly, Teck is also seeing that value and is estimating a great overall impact at that mine.

This is an abridged version of a Q&A to be published in the ore sorting feature in the March issue of International Mining.

Commissioning of Gem Diamonds’ PET and electric pulse technology pilot plant set for Q2

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Gem Diamonds looks to be only a matter of months away from commissioning a pilot plant that could help reduce diamond damage at its flagship Letšeng mine in Lesotho.

In the company’s December quarter trading update, it said the $3 million pilot plant could reach the commissioning milestone at the end of the June quarter.

The plant is set to test out both positron emission tomography (PET) to identify diamonds within kimberlite prior to the crushing process, and electric pulse technology to liberate the diamonds at the operation.

During the company’s Capital Markets Day presentation last year, Gem Diamonds said it had carried out due diligence on the PET technology, a sensor-based sorting system that could be applied to scan kimberlite to identify the diamondiferous rocks.

The technical due diligence concluded that the physics of the PET technology applied in the minerals industry was sound and functional, the scalability challenges identified could be addressed in the development and engineering phase, and value engineering was required to optimise the material handling and associated capital expenditure.

In tandem with this, the company has looked at ways to liberate the diamonds identified by the PET technology without causing damage.

In collaboration with the University of Johannesburg, it has developed a non-mechanical crushing system that uses electrical power to break the kimberlite. During last year, a prototype of this electric pulse technology was developed and successfully tested in Johannesburg, with further testing at higher altitude already being carried out at Letšeng.

Gem said on its website: “The group believes that the advancement of these and other technologies to detect and liberate diamonds within kimberlite will change the future processing paradigm, with a commensurate increase in the overall profitability.”

The pilot plant is initially expected to process tailings as part of the development of these technologies.

Bluestone releases Cerro Blanco feasibility study, weighs up ore sorting

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The feasibility study on Bluestone Resources Cerro Blanco gold asset in Guatemala has indicated the project has, at least, an eight-year mine life ahead of it.

The study, completed by a consortium of independent consultants led by JDS Energy & Mining, shows average output of 113,000 oz/y at an all-in sustaining cost of $579/oz and a capital cost of $196 million (including contingency).

Using a base case of $1,250/oz gold and $18/oz silver, the underground project is projected to generate a post-tax net present value (5% discount) of $241 million.

The deposit is expected to be accessed by the existing 3.2 km of underground development. The current decline will serve as the primary access to the mine for personnel, materials, and haulage of mineralised material to the plant site, according to Bluestone, with annual ore production of up to 460,000 t planned from a combination of long-hole stoping and cut and fill mining.

While the 1,250 t/d operation looks profitable at today’s commodity prices, the company has already identified several potential enhancements that could increase its value, which will be factored into a revised feasibility study later this year.

Darren Klinck, President and CEO, said: “The feasibility study outlines a robust development-ready, underground gold mine with a modest capital expenditure demonstrating superior economics. The mine plan supports the original conviction that the project can be developed into a small footprint, low impact operation that will provide significant opportunities for local stakeholders and generate attractive returns for investors.

“Furthermore, over the next six months as we optimise the project and work to establish adequate project financing, we will see significant opportunity to continue with our objective to upgrade inferred resource ounces and then update the mine plan to incorporate potential meaningful mine life extension, further enhancing project economics.”

In addition to the inferred resource upgrades and potential mine life extensions the company is evaluating over the next six months, there is a possibility of including ore sorting technology in the flowsheet, Bluestone said.

“Preliminary test work in evaluating the potential of using ore sorting technologies was very successful and highlighted an opportunity as a cost-effective method to help reduce potential dilution and enhance the production profile by allowing new areas of the orebody to be economically mined,” the company said.

Bluestone acquired the Cerro Blanco project, which has an indicated resource base of 1.24 Moz of gold and 4.5 Moz of silver at grades of 10.2 g/t Au and 36.5 g/t Ag, respectively, from Goldcorp in 2017. Prior to Bluestone’s acquisition, former owners of Cerro Blanco had invested around $230 million into the project.

HPGR and ore sorting stack up for Vista Gold’s Mt Todd gold project

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Toronto and New York-listed Vista Gold reports recent high pressure grinding roll (HPGR) crusher and ore sorting tests on high-grade samples at its Mt Todd gold project, in the Northern Territory of Australia, have confirmed previous test results.

The company has also announced plans to complete fine grinding and leaching tests in the March quarter and to follow these results with updated prefeasibility study (PFS) economics in the June quarter.

Vista said additional HPGR and ore sorting tests were completed on two, 2.5 t samples from Mt Todd’s Batman deposit containing 1.39 g/t and 1.70 g/t gold, respectively. This testing programme confirmed two important results:

  • HPGR crushing, followed by screening, results in increased concentration of gold in the fine fraction, and;
  • The small amount of gold lost in the rejected material is proportionally lower when sorting higher-grade material.

As with previous tests, the samples were HPGR crushed at the facilities of ThyssenKrupp Industries in Germany and screened at 16 mm. The coarse fraction (+16 mm) was sent to the facilities of Tomra Sorting Solutions in Germany, where two-stage (X-ray Transmission and laser) sorting tests were completed using production-sized and commercially available equipment. The following table summarises the results of the testing programme for each of the samples and compares these results to previous bulk tests on low-grade samples:

Sample

(g Au/t)

 Sorter Feed (+16mm) Sorter Product Sorter Reject Gold Loss (%)
Fraction of Total Sample (%) Grade

(g Au/t)

 Fraction of Total Sample (%) Grade

(g Au/t)

 Fraction of Total Sample (%) Grade

(g Au/t)
1.39 17.8% 0.731 9.4% 1.238 8.4% 0.158 1.0%
1.70 18.6% 0.737 10.3% 1.239 8.3% 0.110 0.7%
Previous Results
0.63 17.5% 0.533 10.5% 0.817 7.0% 0.103 1.1%
0.34 17.8% 0.255 11.0% 0.365 6.8% 0.075 1.5%
0.67 18.7% 0.619 11.3% 0.901 7.4% 0.192 2.0%

Frederick Earnest, President and Chief Executive Officer, said the tests confirmed the benefit of ore sorting for Mt Todd and demonstrated lower gold losses with higher grade crusher feed.

“We attribute these results to the favourable characteristics of the Batman deposit. Simply stated, the gold-containing sulphide minerals and quartz/calcite veining are more easily broken into small particles than the non-mineralised host rock,” he said. “Where this breakage does not result in clean separation from the host rock in the first pass of HPGR crushing, the gold-bearing minerals are easily identified and separated in the ore sorting circuit.”

The results complement Vista’s previously announced fine grinding and leaching test results, Earnest said, adding that he expects them to support additional improvements in the economics of the Mt Todd gold project when the PFS is published later this year.

The crushed and sorted samples have been transported to the facilities of Resource Development Inc, where sample preparation has been completed for assaying and additional fine grinding, leaching and tailings characterisation tests.

Samples are being sent to Core Metallurgy Pty to obtain additional fine grinding data simulating grinding in the horizontal IsaMill and to the FLSmidth Minerals Testing and Research Center to obtain data simulating grinding in the vertical VPX Mill.

“Both tests will target a final product size of 38-45 microns and will generate a sufficient volume of material for subsequent leach tests,” the company said, adding the fine grinding and leach tests were expected to be completed in the March quarter, with final results expected in the following quarter.

The company has completed additional tailings characterisation tests and concluded that no material design changes are required to proceed to the economic analysis using a final grind size of 38-45 microns.

TOMRA upgrades bulk samples at Novo’s Karratha gold project

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Novo Resources has announced gold-rich assay results from concentrates generated by mechanical sorting trials conducted on four bulk samples from its Karratha gold project in Western Australia.

In order to test the potential viability of mechanical rock sorting as a means of concentrating gold from conglomerates at Karratha, four bulk samples were collected, crushed, screened and tested using a TOMRA mechanical rock sorter. High-grade assays from sorted rock concentrates have provided a first indication that this technique is effective at upgrading gold into small volume concentrates.

Mechanical sorting was conducted on material ranging from 6 to 63 mm. Fractions larger than 63 mm and finer than 6 mm are currently undergoing assaying and, once all analyses have returned, an assessment of the effectiveness of mechanical rock sorting will be made, Novo said.

Mechanical rock sorted concentrates range from 0.07-0.48% of total sample mass, a remarkably small fraction. Given the high-grade assays of these concentrates, ranging from 92.1-792.4 g/t Au, it appears gold is being significantly upgraded by mechanical rock sorting, the company added.

“Optimising crushing to reduce volumes of fines and oversize, effectively maximising the amount of material being sorted, should further improve the potential of this technology,” Novo said, adding that mechanical sorting technology could be a critical component of the Karratha gold project moving forward.

Rob Humphryson, CEO and Director of the company, said: “Concentrate grades received from the recent TOMRA mechanical rock sorting trials are impressive, reflecting the capability of the scanning and sorting technology to differentially select gold bearing rock.

“Total system gold recovery efficiency will be fully understood upon receipt of assay results from all process streams and feed size ranges, with these results expected during January 2019.”

Hecla testing out XRF ore sorting at San Sebastian silver-gold mine in Mexico

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Hecla Mining is carrying out ore sorting proof of concept work at its San Sebastian silver-gold mine in Durango, Mexico, CEO Phil Baker told attendees at the Mines and Technology conference this week.

Baker said an algorithm based on X-ray Fluorescence (XRF) technology was determining whether the rock coming through from the mine was ore or waste.

San Sebastian, which produced 3.3 Moz of silver and 25,177 oz of gold last year, recently moved over to underground operations after open-pit mining concluded at the end of 2017. In 2018, it is expected to produce 2-2.2 Moz of silver at a cash cost, after by-product credits, of $9.50/oz, while gold production is expected to come in at 15,000-16,000 oz.

The company’s concession holdings in Durango are in the middle of the prolific Mexican Silver Belt and cover approximately 42,000 ha. Mineralisation in the district is structurally controlled and hosted in sedimentary rocks, with many companies in the region mining high-grade veins.

Hecla is weighing up whether to start mining sulphide ore at the deposit, which could potentially extend the mine’s life by some five years.

While Baker said test work on XRF ore sorting at San Sebastian was ongoing, he did see potential for the technology being applied across the mining sector.

“The real issue with ore sorting is: what is your recovery going to be? How much are you going to lose? And, we’re still working through that (at San Sebastian). But I have high hopes for this being a complete gamechanger for the industry,” he said at the event in London.

“The cost of sorting is quite low. If you’re able to get a high enough recovery, then you can afford to do more productive methods of mining for small tonnage operations. It could completely change how you go about mining.”

Last month, Agnico Eagle Mines said it was in the process of installing an ore sorting pilot plant at its Pinos Altos gold-silver operation, also in Mexico.

Bayhorse ships high grade metallurgical samples to smelters and refiners

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Bayhorse Silver Inc has shipped high grade metallurgical samples (166 –175 oz/t Ag), to identified smelters, as well as to Mineral Solutions, of Coeur d’ Alene, Idaho, to receive firm pricing for extracting and refining silver and other minerals from the its shipping grade concentrate processed through its ore-sorter. The 8 kg of metallurgical samples graded 5,452.42 g/t, 5,175.60 g/t and 5,278.25 g/t Ag respectively, were taken from a homogenous 50 kg underground channel sample from the Bayhorse silver mine.

The company has a Letter of Intent with Minerals Solutions, a Joint Venture between Liberty Refiners of Hayden, Idaho and Irish Metals of Coeur D’ Alene, to process a portion of its upgraded shipping material directly into pure refinery grade 4 X Nine silver. By grinding its upgraded shipping material to -80 mesh at the mine, Bayhorse is better able to provide material that meets Minerals’ specifications for refining.

Upon receipt and acceptance of definitive terms, the company will commence deliveries of upgraded shipping material to Minerals.

Bayhorse CEO Graeme O’Neill comments “by upgrading the mineralization to shipping grade, the company is able to reduce transportation costs per ounce, and minimize processing losses that inevitably occur during flotation concentration. This allows for reduced costs in the processing and smelting/refining options available to us as we upgrade our high grade silver bearing mineralization to shipping grade, and we minimize the 10% losses that normally occur during the flotation process. We are very proud to have developed the Bayhorse silver mine at a cost of $1.00 per inferred silver resource ounce”.

The company is currently tramming over 1,200 t of already extracted mineralization from the high grade Goldilocks zone, 1,100 ft inside the mine at the extreme western end of the main haulage, to the newly built all weather storage pad. The picture shows that pad ready for all-weather cover installation.

The mineralized material is then passed through the crushing circuit, where it is reduced to between 8mm and 20mm – 25mm in size, to allow for greater selectivity when processed through the Steinert XRT ore-sorter at rates up to 40 t/h.

The sorter removes up to 95% of the non-mineralized and low grade material from the process stream, increasing the silver grade to the shipping grade of 103 oz/t Ag (3,000 g/t) or better prior to being shipped to the smelter/refiner.

Newcrest Mining after Telfer profitability jump with ore sorting technology

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Newcrest Mining has confirmed ore sorting technology is one of several innovations it is currently investigating at group level to increase profitability and build on its substantial resource base.

The gold and copper miner’s technology and innovation team spoke at length at the company’s recent investor day about how new developments could enable the miner to produce more, lower costs, increase mine lives and improve safety across the group.

Next generation caving and hydrometallurgical processing, plus robotic mining, was part of the company’s five breakthrough strategies target by 2020, as was selective processing and what it called “sustainable mines”. The latter could see an increased focus on mine electrification and the use of renewable energy.

X-ray ore sorting tests carried out by TOMRA on the company’s Telfer operation in Western Australia had already shown impressive results, according to Executive General Manager of Gosowong and Telfer, Phil Stephenson.

Results to date indicated ore sorting could triple the grade and recover nearly 80% of the gold in the scats stream, according to Stephenson.

Over three months from August, 100,000 t of feed had been tested in a >160 t/h pebble sorting circuit at an average gold and copper feed grade of 0.18 g/t Au and 0.04% Cu. Some 79% of gold and 60% of copper had been recovered with a mass recovery to product of 26% and product grades of 0.56 g/t Au and 0.08% Cu, according to Newcrest.

Following these results, feasibility work had already commenced to design and install a full-scale plant at the scats stream expected to increase overall gold recovery at Telfer by 2-4%, Newcrest said.

And, Stephenson admitted the company is already weighing up the use of this technology on Telfer ore, with a sample from the West Dome open pit recently sent off for testing.

Stephenson didn’t want to say too much on the results, but indicated they had “exceeded our expectations”.

“If we can get this to work at the front end, we could go from two [processing] trains to one,” he told investors last week, adding this would take a big chunk out of the operation’s cost base.

The ore from the Telfer mining operations is processed by a large, dual train, communition circuit followed by flotation and cyanide circuits, which produce gold doré and a copper-gold concentrate. In the financial year ending June 30, 2016, Telfer produced 462,461 oz of gold and 18,940 t of copper.

Should the technology prove worthwhile at Telfer, expect Newcrest to look to apply it elsewhere across its operations.

Agnico Eagle Mines looks to ore sorting for higher-grade gold-silver feed at Pinos Altos

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Agnico Eagle Mines is in the process of installing an ore sorting pilot plant at its Pinos Altos gold-silver operation in Mexico as it looks to improve the feed grade to its processing facilities.

The announcement came in the company’s September quarter financial results, which also mentioned a planned trial of automated underground mining equipment at the La Ronde Zone 5 mine in the Abitibi region of Quebec, Canada.

Agnico said testing of the ore sorter was expected to begin later this month and continue for some six months.

“Over this period, samples will be processed from all the orebodies to determine the merits of implementing the technology in Mexico,” the company said, adding that similar ore sorting pilot testing was being considered at the company’s other operating regions.

Pinos Altos is an open pit and underground operation that produced close to 250,000 oz of gold last year.