Probabilistic Targeting for Mesothermal Gold Mineralisation

Over the last 12 months, Monarch Gold Mining Company has developed a large tenement portfolio in the Eastern Goldfields of Western Australia through mergers and acquisitions. For Monarch, SRK took on a geological review of the area and generated a series of ranked exploration targets.

Monarch’s tenement package covers the approximately 100km strike length of the Ida Fault, which separates the Eastern Goldfields and Southern Cross provinces of the Yilgarn Craton. Historically, the area has abundant workings, now under care and maintenance. The Archaean Greenstones of the Yilgarn host significant mesothermal gold mineralisation in the region.

Initially, the project focused on improved regional scale interpretation. New magnetic data were processed and used to review the regional geological interpretation. SRK partners, ioGlobal, validated and analysed the geochemical data and through site work, reviewed the local, deposit scale controls on known mineralisation.

SRK employed a Bayesian Probabilistic method to rank targets for exploration. This method identifies key features of the mineralisation model and mathematically codes exploration information to integrate a range of data sources, following this general process:

  • Key features are identified, such as fault jogs or lithological contacts, and a probability matrix is developed, based on proximity to features, and their cumulative effects
  • These features are then automatically picked from the regional GIS using a simple search algorithm and classified as either fluid sources, pathways or traps
  • Individual maps for fluid source, pathway and trap are constructed using the probability matrix
  • The probability maps are combined to produce an exploration ‘hotspot map’ for each model, with targets and rank generated by contouring the map

The method successfully identified areas of known mineralisation. Subsequently, SRK generated 160 targets using three models, including ten high priority zones or trends, where Monarch will now focus its exploration.

Owen Herod: oherod@srk.com.au


 

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