- Large scale potential has been confirmed at Impact Minerals’ Blackridge Gold project in Queensland
- Gold was returned from all 12 trenches completed averaging 0.36g/cubic metre
- Further sampling is required to establish the gold distribution and once known it will have a significant influence on the strip ratio of potential mines
Impact Minerals has confirmed a large scale potential at its Blackridge Gold project in Queensland.
These results from Impact’s second phase of bulk sampling at its project has confirmed the potential for significant volumes of free digging oxide material.
Exceptional gold recoveries of at least 95 per cent and some greater than 98 per cent were recovered.
Following the successful results from the phase 1 sample program a second-hand mobile water processing plant capable of processing up to 50 tonnes of material per day was purchased and commissioned by Impact for phase 2.
The second program comprised of 17 samples processed in four separate groups.
The first group consisted of 11 samples between 11.6 tonnes and 14.7 tonnes in weight taken from 11 trenches over a length of 1000 metres. It targeted a two metre thick zone around the target.
However, one 900 kilogram sample dug in phase 1 could not be processed because excessive clay was also processed. Sticky clay can prevent the release of gold by the simple physical trapping of gold particles.
Groups two and three took two samples each with group two taking samples from an additional trend to test a four metre thick part of the profile. For group three, two smaller bulk samples of soil that were taken from phase 1 that previously couldn’t be processed were processed.
Finally, for group four, one sample of oversized clay material that consisted of all oversize material was processed as a check on the effect of the clay.
The 12 trenches and one sample from phase 1 were taken at varying intervals between 50 metres and a few hundred metres over a strike length of 1000 metres.
All of the samples were free digging which supports Impact’s belief that there are potentially large volumes of easily mineable oxide material in the top four to five metres at Blackridge.
While the depth of the oxide material is unknown previous drilling in the area indicates that relatively easily processed material may be present down to at least 25 metres in places.
Every trench returned gold values ranging from 0.07g/cubic metre to 2.17g/cubic metre.
Eight of the 12 trenches returned gold nuggets with varying grades. In particular one of the trenches returned 11.5 grams of nuggets from 12 tonnes of rock to give a grade of 2.17g/cubic metre.
Phase 2 has demonstrated the potential for large volumes of easily mined and processed material from a surface depth of at least five metres.
Further sampling is required to establish the grade distribution and once known it will have a significant influence on the strip ratio of any potential open pit mine.
Previous drilling has demonstrated that gold is present periodically throughout the entire 100 metre thick sedimentary package at Blackridge.
The next practical step for Impact will be to commence much larger sampling programs on the granted mining lease. This will begin once the application has been granted.