The ore sorting project – objective: improve productivity and extend life-of-mine
Among these activities was the ore sorting project, started in 2015 in collaboration with TOMRA Sorting Mining, with the objective of rejecting low grade material in coarse particle size. By separating sub-economic material before entering the more cost-intensive wet processing, the project would address the bottleneck at the wet section and improve productivity by increasing the feed grade. An added benefit expected from the project would be the longer life of the mine.
Three main factors indicated that sensor-based particle sorting for waste rejection would be effective at the San Rafael mine. First of all, the high absorption of transmitting X-Rays of tin contained in Cassiterite; second, the structures of Cassiterite which are large enough to be detected by X-Ray Transmission (XRT) technology due to the way its mineralization occurs; finally, the significant degree of liberation of sub-economic waste on the particle level that may be subject to sensor-based particle sorting.
In order to assess the feasibility of the project, TOMRA conducted metallurgical tests on geological samples from San Rafael, followed by Performance Test Work. The tests showed the deposit of the mine to be especially suited for XRT technology due to the presence of 70 to 80% of uneconomic particles that can be rejected over a wide size range, from 6 to 70mm. The project was approved and, in view of the significant economic potential, it was fast tracked and completed in just 14 months. TOMRA and its partner in Peru, which supplied and installed the XRT sorting system, worked closely with MINSUR throughout the six-month ramp up period.