ORE SORTING
its lead-zinc ore . The company has been able to sort lead-zinc ore with a raw ore grade of less than 4-6 % and a processing capacity of 140 t / h , with sorting grain sizes of 10-90 mm . The Circle Series has achieved a recovery rate of over 95 % and a rejection rate of more than 30 %, enriching the raw ore grade by 1.4 times , according to Zhou .
In Shandong Province , China , Shandong Xinhui Construction Materials was looking to recover economically valuable gold from its waste rockpiles , reaching out to HPY Technology to sort ores that contained this valuable gold using the Circle Series . The Circle Series enriched the gold by 9.73 times and increased the raw ore grade from 0.11 g / t Au to 1.10 g / t Au by concentrating these waste rockpiles , Zhou told IM . The grain size range the company sorted was 5-28 mm , displaying the Circle Series ’ ability to sort even small grain sizes .
Zhou says HPY Technology has cooperated with Zijin Mining , China National Gold , Chinalco , China Minmetals , Zhongjin Lingnan Nonfemet , China Tungsten and Hightech Materials , and over 70 other well-known mining enterprises in China and internationally . By the end of 2022 , it had sold over 400 intelligent ore sorting machines , with its products used in over 100 mines .
“ With innovations like the Circle Series , HPY Technology looks to continue changing the mining industry for the better ,” Zhou concluded .
Offering a performance step change
Like TOMRA and Steinert , Scantech is benefitting from an uptick in demand for – and interest in – ore analysis and sorting solutions from the gold sector .
The company released its GEOSCAN GOLD premium elemental analyser back in 2021 , and the enquiries and interest for this solution , since launch , have been consistent .
The analyser , which builds on Scantech ’ s GEOSCAN-M high-performance elemental analyser and leverages PGNAA conveyormounted sensors , provides previously unattainable levels of risk-free , real-time measurement performance to the resources sector to help digitalise and control ore quality , according to the company .
Able to measure elements in primary crushed rock in conveyed flows at < 100 t / h to > 10,000 t / h irrespective of belt speed , particle size , mineralogy , dust , moisture , or segregation / layering , GEOSCAN GOLD can register gold directly over 5-10-minute increments and other elements , including proxies for gold , with high precisions over each 30 seconds of flow , according to the company .
Henry Kurth , Chief Marketing Officer at Scantech , says the company has recently been consolidating its experience in direct gold measurement and how it can be applied for optimising process performance in recent years , with initial work having proven effective . This was displayed in a recent paper co-authored by Scantech and Newcrest Telfer , which was presented at the IMPC Asia-Pacific 2022 conference in Melbourne , Australia .
Kurth continued : “ Further sales occurred to gold companies planning to use the gold measurement to develop an understanding of the ore variability and opportunities to benefit from the measurement .”
Scantech anticipates further interest in both direct gold measurement and measurement of proxies for gold , where applicable , in conveyed ore-feeding process plants , he said .
And the company expects representative , direct gold measurement to be carried out in under 5-10 minutes eventually , followed by potential bulk ore sorting applications on shorter conveyor belts .
Outside of gold , one of the largest copper-zinc mines in the world – Antamina – has recently installed and calibrated a Scantech PGNAA-based analyser for bulk ore sorting conveyor flows of ore at target throughput rates of 4,000-8,000 t / h .
Antamina , co-owned by Glencore , BHP , Teck Resources and Mitsubishi , is part of a growing list of mining companies investing time and money in improving their understanding of ore sorting across the process flowsheet , according to Kurth .
He explained : “ Various technologies are being evaluated at different stages in the flowsheet with less precise , qualitative , surface measurement techniques ( XRF , hyperspectral , laser-induced breakdown spectroscopy , etc ) applied closer to the mine face and on blasted rock , and more representative techniques involving penetrative , quantitative analysis on conveyed flows ( eg PGNAA / Pulsed Fast Thermal Neutron Activation ( PFTNA ) and magnetic resonance ( MR )).”
“ We have also seen more interest from
Scantech ’ s GEOSCAN GOLD premium elemental analyser builds on its GEOSCAN-M highperformance elemental analyser ( an installation pictured ), which leverages PGNAA conveyormounted sensors
engineering companies , such as SRK , DRA Global , Worley , ABH and others , as they continue to seek the best techno-economic outcomes for their mining clients .”
While these companies are asking the right questions when it comes to realistic sensing technology and likely implementation performance , evaluating “ bulk sortability ” is not purely a theoretical exercise , Kurth warned .
“ Each mine ’ s orebody , mining method , blasting , crushing , materials handling and economics are unique in some way so that is why the approach has been to install sensors first to gather data ( digitise mined flows , typically on conveyors after primary crushing ) to develop a practical understanding of mined material variability magnitude and frequency as this will eventually determine the suitability of bulk sorting ,” he said .
Testing customer samples is something Scantech provides the industry for free .
Once measurement performance is effectively guaranteed , operations purchase the units for conveyed flows knowing they can absolutely trust the data , and they can then observe quality variation ( rather than trying to find ways of predicting it with mixed results ) and get used to the data being generated for the small increments of material , Scantech says .
This can form the basis for a bulk sorting strategy if it stacks up both operationally and economically . It is also part of an education process Scantech is going through with the wider industry to ensure all sorting projects mining companies and engineering firms engage in provide value to the operation in question .
Kurth explained : “ In particle sorting , the sensor is selected for the ability to determine characteristics that indicate a potential value of a particle , hence a point solution . Bulk sensing is a
40 International Mining | MARCH 2023