Unmined mineralisation measuring 71 metres at 11.02% zinc equivalent has been tapped into by Polymetals Resources Ltd (ASX:POL) during reverse circulation (RC) drilling at the newly acquired Endeavor Silver-Zinc-Lead Mine in NSW.
Investors have responded positively to the drill results with shares as much as 35.4% higher this morning to $0.44.
High-grade intersections
The South Lode is the focus of the drilling, which has returned high-grade intersections:
- 71 metres at 0.43 g/t gold, 272 g/t silver, 3.6% zinc, 4.2% lead and 0.13% copper from 107 metres to 178 metres (11.02% zinc equivalent);
- including 34 metres at 0.76 g/t gold, 492 g/t silver, 7.3% zinc, 4.8% lead and 0.14% copper from 144 metres (19.0% zinc equivalent); and
- including 8 metres at 0.89 g/t gold, 91 4g/t silver, 8.9% zinc, 5.3% lead and 0.16% copper from 154 metres (29.2% zinc equivalent).
The Endeavor Mine phase one drilling program, which wrapped on March 5, consisted of 21 RC drill holes across 2,868 metres.
The major focus of the program was to generate measured resources hosted within the unmined near-surface North Lode.
South Lode comes through
It was the South Lode that delivered the surprise during drilling though, where five holes of the 21-hole program tested the presence of remaining measured resources.
Historically, the Endeavor South Lode hosted a very high-grade supergene resource discovered several years after mining operations had commenced in 1982.
Significant quantities of native silver (contained within vughs) had been encountered during underground development activities.
The discovery led to the mining and processing (over several campaigns) of some 100,000 tonnes of supergene ore during the latter part of the 1980s, which contained roughly 16 million ounces of silver and 29,000 ounces of gold.
The supergene ore mined was soft and friable which provided underground mining challenges; however the significant contained gold and silver grades that justified the expensive Square (NYSE:SQ) Set Mining method applied at the time.
The mine operator, Pasminco, recognised the residual value of the supergene flotation tailings and stockpiled the same for later treatment.
In 1992, Polymetals chairman David Sproule purchased the supergene tailing from Pasminco – 84,000 tonnes grading 550 g/t silver and 3.5 g/t gold) – treating it off-site to recover silver and gold applying a variation to conventional cyanide leaching and cementation.
In 1996, the South Lode area of the Endeavor Mine suffered an uncontrolled cave resulting in the assumed vertical displacement of remaining resources.
During Polymetals 2022 due diligence of the Endeavor Mine, it was discovered that a quantity of high-grade South Lode resources may remain intact. This prompted the recent limited drill testing of the zone and of the two holes, for which assays have been received.
These assays confirm that high-grade South Lode mineralisation remains.
Oxidised mineralised zones made drilling of the zone challenging, with PSL021 abandoned above target, but follow-up drilling is nevertheless justified to quantify volume and grade of the South Lode, to support resource estimations and to obtain geotechnical information to help determine best options for mining.
Near-surface, in situ mineralisation
Polymetals Resources executive chairman Dave Sproule said: "It is most encouraging to know that part of the near-surface South Lode remains in situ at Endeavor.
“We will plan to further test the zone to quantify metal endowment over the coming months.
“The elevated silver grades and contained gold we are seeing both within the unmined North Lode and remaining South Lode is also pleasing as it provides potential to generate significant value upside following conventional lead and zinc flotation with hydrometallurgical leaching of gold and silver.
“Following receipt of all assays from the phase one RC drilling program, metallurgical test-work will be expedited to confirm metal recoveries, additional South Lode drilling will be undertaken, a new resource estimate will be completed, and mining reserves determined for both the North and South lodes.”