Great Boulder Resources (ASX:GBR) have reported new metallurgical test results conducted on a sample of high-grade drill chips from the Mulga Bill prospect at the Side Well Gold Project in Western Australia.

Earlier this month, Great Boulder reported series of three leach tests which examined the effect of various grind sizes over a 48-hour period, with all tests achieving similar recoveries in the range of 87.2% to 88%, indicating that gold recovery is not affected by grind size.

Great Boulder completed a fourth leach test this week which increased overall gold recovery to 99.7% by increasing the cyanide concentration, resulting in a residue or tails grade of 0.1g/t Au.

Gravity recovery in this test was consistent with the previous three tests at 62.1%.

Excellent, fantastic, sensational!

GBR managing director Andrew Paterson said this is a “fantastic result.”

“Achieving an overall gold recovery of 99.7% on a high-grade sample is excellent, but only leaving 0.1g/t in the tail is sensational.”

“For this test IMO increased the maintained cyanide level from 300ppm to 400ppm and used a coarse grind size of 150 μm, which was enough to improve gold recovery from 87.7% to 99.7%.”

Next on the agenda  

“This is another step in the company’s sense of what’s making Mulga Bill tick”, Paterson added, “With more comprehensive studies on other mineralised zones and on drill core to occur over the next few months”.

Future testing will examine the metallurgical characteristics of other styles of mineralisation at Mulga Bill, including lower-grade zones and areas with significant chalcopyrite (copper) and associated gold mineralisation to build up understanding of the overall metallurgy.

Mineralised samples from drill core will also enable physical testing of the crushing and grinding parameters of different mineralisation styles.




This article was developed in collaboration with Great Boulder Resources, a Stockhead advertiser at the time of publishing.


This article does not constitute financial product advice. You should consider obtaining independent advice before making any financial decisions.