Ore sorting is a very broad concept that includes sorting by grade, particle size, and mineralogy across many different mineral processes. Continuous analysis of ore in base and precious metal applications is best accomplished using rapid online elemental analysis, with either PGNAA (Prompt Gamma Neutron Activation Analysis) or PFTNA (Pulsed Fast Thermal Neutron Activation).
What are the benefits of bulk ore sorting?
Social license to operate is one of the biggest issues facing the mining industry today. Often, the footprint, water, and energy consumption are at the top of the list of community concerns. Bulk ore sorting can have a positive impact on all three of these.
Improving the economics of marginal operations
Declining grades can lead to revenue reduction if throughput is at a maximum. Traditionally, the solution has been to increase capacity to offset this through adding to the plant infrastructure by large capital investment. Bulk ore sorting has the potential to either delay or eliminate this capital spend, while delivering higher grade material to the mill. The increased recovery and profitability results in an extension of the mine life, increases the return on investment in the mine, and delays costly site rehabilitation.
Why is PGNAA/PFTNA technology the right choice for bulk ore sorting?
Online elemental analyzers using PGNAA or PFTNA enable early and accurate measurement of the grade of material being sent to the process plant and enables a decision to sort material that is below target grade and divert it to a low grade or waste stockpile. This enables a plant to increase the average grade of ore being processed to maximize metal recovery. Additional benefits include the opportunity to divert or bypass material that is detrimental or not economically viable to the process and in doing so reduces the usage or water, power and reagents.
PGNAA technology has been used for decades to provide online elemental analysis of material on conveyor belts and has been particularly prominent in the cement and coal markets. As the world progressively moves away from the use of isotopes, the mining industry is moving towards the use of a neutron generator as the source of neutrons instead of Cf-252.
For more information about how to develop a bulk ore sorting system using an online elemental analyzer, read this application note.