Magnetic Resonance

Magnetic Resonance (MR) detects the signature of ore minerals via sensors. As a result of their crystal structures and properties of their atomic make-up, many ore minerals possess a signature resonant radio frequency. With negligible overlap of signature resonant frequencies, MR easily discriminates between ore minerals, eliminating the requirement for recalibrations. The unique resonant frequencies also mean that MR measurement benefits from a very high signal-to-noise ratio, and can generate highly precise measurements at much faster speeds and at much higher resolutions than other bulk sensor types.

MR detects the signature of ore minerals by sending radiofrequency pulses into the ore stream via non-contact sensors. The sensors detect the signatures via an echo, in a measurement process completed in under a millisecond. Due to the discriminate nature of the mineral resonances, the echo’s magnitude is proportionate to the number of crystalline unit cells in the ore mineral.

Key Attributes

  • Deep Sensing

    The radiofrequency band used by MR can penetrate metres into rock, meaning that measurements are accurate for whole-of-ore.

  • Highly Selective

    The lack of overlapping mineral resonances means MR can differentiate between the ore resonance of one and another, with the mineral quantified by the scale of the MR echo.

  • Seamless Calibration

    Since MR measurements are clean, an accurate factory calibration can be pre-set, meaning that ongoing recalibration is not required.

  • Surface Insensitivity

    MR is a pure bulk sensing solution, which means it doesn’t require a clean surface, narrow size distribution, or pre-mixed presentation to produce accurate data.

  • Operational Safety

    Utilising non-ionising radiation, MR is safe to deploy in close proximity to workers, with its radio signal strength in compliance with workplace exposure standards.

Mineral Characterisation

  • Most copper sulphide minerals can be detected directly using MR, while others can be detected by
    association ​
  • The sensitivity of each mineral to detection also varies from mineral to mineral​
  • The higher the sensitivity of the mineral to MR, the more quickly and accurately the MR system can deliver a measurement ​
  • The MR sensor is highly penetrative and can measure large throughputs on fully loaded conveyor belts​
  • The measurement response time is rapid, thus allowing diversion of different grade streams in an ore sorting application​
  • 1 mineral is measured per MR Analyser, multiple analysers can be installed on a single conveyor belt​

 

MineralCategorySensitivity
ChalcopyriteCopperHigh
CubaniteCopperHigh
CovelliteCopperMedium
ChalcociteCopperMedium
EnargiteCopperLow
TennantiteCopperLow
Cuprite+delafossitesCopperHigh
TenoriteCopperLow
ArsenopyriteHigh
OrpimentHigh
RealgarHigh
LollingiteHigh
NiccoliteMedium
HematiteIronHigh
MagnetiteIronVery High
MaghemiteIronHigh
PhyrrhotiteIronHigh
Bismuthinite+ othersMedium
Stibnite+othersHigh
ZirconLow
CobaltiteHigh

Bulk Ore Sorting

Bulk Ore Sorting differentiates minerals from waste to improve ore grade. The value proposition of effective bulk ore sorting is significant. Supported by the development of accurate new sensing technology, bulk ore sorting is now able to progress from small mining operations to globally significant mines.

Bulk ore sorting systems are capable of separating valuable minerals from waste, improving the head grade conveyed to processing plants. Beyond the improvements to mine productivity, bulk ore sorting can also decrease water and electricity consumption and create efficiencies from mine planning to extraction.

Bulk ore sorting is different from particle sorting. In bulk ore sorting, a single average grade measurement is generated for a ‘’pod’ or ‘parcel’ of material. The size of the pod is determined by the measurement speed of the sensor and the throughput of the conveyor. For example, if the measurement time of the analyser is 5 seconds and a conveyor is carrying 3,600 tonnes per hour, or 1 tonne per second, a pod would be equal to 5 tonnes. In this example a grade measurement would be provided for every 5 tonnes of material. Based on that measurement, downstream diverting systems would direct high quality ore to an upgraded stream and waste material to a reject stream.