- Musgrave Minerals (ASX:MGV) has completed initial test work on the new Starlight lode at Break of Day, situated on the Company’s Cue Gold Project.
- Around 98-99% of gold was recovered from conventional gravity and cyanide leach tests, highlighting the remarkable recovery of the yellow metal.
- The gravity-only recoveries in fresh rock and transitional zones were 80%, while oxide zones had more than 50%.
- Resource Update for Break of Day is slated for November 2020, and regional drill testing of Starlight analogue targets is ongoing within the belt.
The strategic efforts of Musgrave Minerals Limited (ASX: MGV) have once again yielded exciting results, taking its exploration at Cue Gold Project to new heights. Perth-based gold and base metals explorer has announced the conclusion of the initial metallurgical test work on the Starlight gold lode at Break of Day with exceptional results.
Following the announcement, Musgrave shares soared 2% to $0.500 on 2 November 2020.
ALS Metallurgical Laboratorie undertook the test work which was managed and reviewed by Ivan Hunter at Minelogix.
The test work has highlighted excellent total gold recovery on composite samples with gravity and cyanide leach recoveries averaging around 98-99%. Meanwhile, amenability to conventional gravity as well as leaching techniques using standard reagents has also been indicated by the test work results.
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Metallurgical Sample Selection
The four composites which were collected from 16 representative drill holes across strike and vertical section included two primary or fresh composites (SFMC01 and SFMC02), one oxide (SOMC01) and one transition (STMC01)
All individual samples with ≥1m footwall and hanging wall material were diluted, having overall dilution of typically 25%.
On the two Fresh mineralised master composites, Bond Ball Work Index tests were performed. The results indicated Bond Ball Work Index value of 11.2-13.1 kWh/t for Starlight primary (fresh) mineralisation, which is lower than many primary Yilgarn gold deposits.
Gravity and Cyanide Leach Test work
Amenability of the varying types of Starlight regolith gold mineralisation to gravity and cyanide recovery was tested. It was done using small scale tests undertaken on all four composites. Significantly, a laboratory size 3-inch Knelson centrifugal concentrator was used on 3kg batches at a feed size of 80% passing 212µm.
All mineralisation types highlighted high gravity-only gold recovery with the transition and fresh exceptionally high in recoverable gold (tested at ~80% recovery). Meanwhile, the oxide sample recovered feed gold of >50% to the gravity-only concentrate stream.
Gravity circuit was included in the processing to reduce the spikes in feed grade, while also slowing coarse gold leaching which enters the downstream carbon-in-leach circuit.
Cyanidation Test work Observations
All the mineralised samples from Starlight are classified as free milling. They have extraction typically ≥99% at a grind size of 80% passing 75µm.
Cyanide leach kinetics are fast with most of the gold leached for all the sample domains within the first eight hours. As anticipated, the rate and extent of extraction were slightly slow at coarser grinds. In the primary samples, very low residues of <0.1 g/t Au was witnessed.
Cyanide consumption from the tests are regarded moderate for a typical Yilgarn gold ore and was concluded at an established grind size of around 80% passing 75µm.
In all samples, cyanide solubilisation of copper was generally <15% leached, resulting in low copper solution values of less than 15ppm. Meanwhile, lime consumptions were typical of the lithologies treated in Perth tap water which was used as a standard base case.
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- Initial follow-up drilling is underway along strike at Target 2, which is a new robust gold intersection southward of Starlight. The assays are pending.
- The Company intends to conduct further drilling to test the potential new gold lode present south of White Light.
- Resource Update interpretation for Break of Day and regional drill testing of Starlight analogue targets is ongoing within the belt, with outcomes for both expected in November 2020.
More than half of the ongoing Phase 2 aircore drilling program of a planned 21,900m is completed at the quarter-end. The program is targeted to high-priority gold targets testing on Lake Austin.