Canadian Mining Journal


ORE SORTER: Tomra’s ore sorting technology improves productivity at San Rafael

Minsur operations Credit: Tomra

Minsur operations Credit: Tomra

PERU – Minsur, a Peruvian mining company, operates the San Rafael underground tin mine in Peru.  In 2015, the mine contributed an estimated 6% of the world’s total tin production. That year, Minsur initiated activities to safeguard the future value of its asset, addressing challenges such as declining head grades and tackling operating costs.

It undertook an ore sorting project aimed at improving productivity and extending the life of the operation.

The ore sorting project was conducted in collaboration with Tomra and was aimed at rejecting low grade, coarse material. By separating the sub-economic material before it enters more cost-intensive wet processing, it focused on increasing the feed grades and increasing the mine life.

Three factors indicated that sensor-based particle sorting for waste rejection would be effective at San Rafael. Firstly, the tin is contained in cassiterite which allows for high absorption of transmitting X-rays, secondly, the structures in this mineral are large enough to be detected by X-ray transmission (XRT) technology. Thirdly, the waste material was liberated to a significant degree on the particle level that would be subject to sensor-based sorting.

In order to assess the feasibility of this project, Tomra conducted metallurgical tests on rock samples from San Rafael as well as performance test work. The tests showed the deposit would be well suited for XRT technology due to the substantial presence of uneconomic particles which could be rejected over a wide size range.

The project was completed in 14 months with Tomra and a Peruvian partner supplying and installing the XRT sorting system. The companies worked closely with Minsur over the six-month ramp up period.

The ore sorting plant delivered a fast payback with a number of positive impacts to the operation.

Minsur’s capital outlay was paid back in just four months.

The XRT system has reduced costs at San Rafael by increasing plant throughputs and recoveries and has also extended the mine life as it allows Minsur to mine low-grade ore which would have previously been excluded from the mine plan.

It has also decreased the amount of material headed to the tailings disposal system as the sensor-based ore sorting system reduces the amount of waste headed for processing.

Due to the success of this project, Minsur plans to include XRT sensor-based ore sorting in future projects.

Tomra provides technology-led solutions that enable the circular economy with collection and sorting systems that optimize resource recovery and minimize waste in the food, recycling and mining industries. Tomra’s Mining Sorting division designs and manufactures sensor-based sorting technologies for the mineral processing and mining industries.

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