Results from initial metallurgical test work at Zenith Minerals’ (ASX: ZNC) Split Rocks gold project in Western Australia has returned high gold recoveries in all three mineralised sample types tested.
The Perth-based explorer today reported an average gold recovery greater than 92% from the samples, which are considered representative of the gold mineralisation drilled to date at the Dulcie laterite pit target.
Other key findings from the tests include: a gravity gold content ranging from 12.4-34.7%; low leach residue grades of 0.03-0.07 grams per tonne and rapid leach kinetics with the bulk of the extraction completed at the eight-hour mark; low cyanide consumption averaging 0.38kg per tonne of sodium cyanide; and all three samples ground to 80% passing 90 microns.
According to Zenith, the results confirmed that even relatively low-grade gold mineralisation should be included in the drill target mix.
Today’s announcement follows news from earlier in March that new drilling results had extended and confirmed new gold zones at Split Rocks.
Results show commercial leach processing is likely to be effective
This initial test work also indicated industry standard commercial cyanide leach gold processing techniques such as carbon-in-pulp (CIP) or carbon-in-leach (CIL) are likely to be effective on the Dulcie pit-style mineralisation.
In addition, the leach results on coarse, raw reverse circulation drill chips open the possibility that heap leaching may be effective on Dulcie laterite pit transition-saprock material.
Zenith executive chairman Peter Bird said these results make the gold extraction process look “straightforward”.
“It is still early in our evaluation journey, but the information gathered to date also gives us a number of potential process alternatives should we define sufficient ore tonnes.”
“We will continue with our drilling with these positive data points in mind,” he added.
Zenith said additional gold leaching is now planned on both coarse fresh and transition-clay material, while a comprehensive test work program based around diamond drill core, column leach and screening tests will be required to provide more definitive metallurgical results.
Drilling is scheduled to continue at the Split Rocks project for at least the next six months, focused on defining a gold resource.
Split Rocks is located within the Southern Cross region of WA, about halfway between Perth and Kalgoorlie.
An initial 12 high-quality gold drill targets was recently expanded to 18 identified targets in the north-eastern sector of Zenith’s 100% owned tenure.