Physical Separation 2019

Event: Physical Separation 2019

Date: 13-14 June 2019

Location: Falmouth, Cornwall, UK

Paper: Gangue rejection in practice - the implementation of Grade Engineering® at the Minera San Cristóbal Site



Gangue rejection in practice - the implementation of Grade Engineering® at the Minera San Cristóbal Site


Grade Engineering




Dr Ben Adair, Dr Luke Keeney, Mr David King and Dr Michael Scott







Abstract text:

There are a number of potential technology opportunities to effect up-front gangue rejection in the minerals sector. CRC ORE has been working with several of its mining participants to assess the efficacy of a range of such technologies, assessed across a variety of operations and commodities. Our “Grade Engineering®” approach references a suite of integrated technologies to effect gangue rejection across several separation “levers” – dependant on the textural amenability of the ore domains concerned.

This paper details recent implementation trials of Grade Engineering® at the Sumitomo-owned Minera San Cristóbal operation in Bolivia. This Pb/Zn/Ag mine operates with some of the lowest head grades in the Industry – yet ranks as one of the most profitable. The implementation strategies at the site trails are presented and the upgrading of “mineralised waste halos” to ores is detailed. Preliminary results indicate a significant financial opportunity exists in converting these low-grade marginal and mineralised wastes to ore feed. This opportunity was confirmed through detailed meso-sampling and the execution of a production scale trial confirming the scalability of predictive characterisation tests and magnitude of upgrading potential. Some two thirds of the total metal value of this material reports to 25% of the “Grade Engineered” mass - contained in the -19mm fraction. An upgrade factor of 2.7 readily converts these mineralised wastes to high grade ore feed-stock. Exploitation of this material will result in a predicted minimum value uplift at the operation of some +450M$ in profit or +257M$ in NPV from the existing mine plan. This success has implications for unlocking “hidden value” across the sector.




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