Marmota Ltd (ASX:MEU)’s first Bulk Leach Extractable Gold (BLEG) analysis of gold samples from its Aurora Tank Project in South Australia has yielded grades in excess of 200 g/t gold.
The BLEG assay results from Sample 1 and Sample 2 of 227 g/t gold and 235 g/t gold are the highest ever gold assays to date at Aurora Tank, while the average BLEG grade of 197 g/t gold over 1-metre represents the new highest grade over 1-metre at the project.
This is 19% higher than the previous average fire assay result of 165 g/t gold for the same interval.
Testing bonanza grades
“Companies that are lucky enough to get bonanza grades are sometimes reluctant to re-test them, because, due to the nugget effect, new fresh samples can sometimes differ markedly from the original,” Marmota chairman Dr Colin Rose said.
“Marmota has re-tested the bonanza grades using the high precision large sample BLEG technique – not just once – but by taking four fresh samples ... with ALL four samples returning bonanza grades, and the average grade increasing by a further 19%, and yielding our highest ever gold assays at Aurora Tank.
“This is a wonderful verification of the bonanza grades at Aurora Tank, and particularly exciting and relevant for us with the next round of RC drilling at Aurora Tank about to commence. Further announcements about the forthcoming RC program will provide more detail shortly.”
Shares were as much as 9.09% higher to A$0.048 after the announcement was released.
Results in detail
The first high-grade test was carried out over Hole 20ATRC324, collecting four samples (each of 1 kilogram) over the interval from 66-67 metres downhole:
Samples one and two show the highest ever gold assays at Aurora.
A second high-grade test was carried out over Hole 20ATRC224, collecting four samples (each of 1 kilogram) over the interval from 55-56 metres downhole:
The average grade for the second test of 42.5 g/t gold over 1-metre confirmed the original high-grade interval reported by the fire assay result of 41 g/t.
The importance of BLEG testing
The assaying of high-grade intersections via the BLEG method is an important step for resource estimation and to test the accuracy of bonanza fire assay grades.
It is much more effective than fire assays, which only examine a small sample of material.
In MEU’s case, the high-precision BLEG method has not only confirmed the bonanza results but yielded even higher average grades over the same intervals, and as stated, has returned the highest ever gold assays at Aurora Tank of 235 g/t gold over 1-metre.
The BLEG tests were designed to provide confidence for resource estimation and confirmation of high-grade fire assay results at Aurora Tank, and as a check against so-called nugget effects.
The precision of BLEG test results is high due to much larger sample sizes.
Marmota collected four new large 1-kilogram samples from the original 1-metre split bags at Aurora Tank.
Each large 1-kilogram sample was then pulverised and a crushed sample was then leached in a cyanide solution for 24 hours to extract its gold content.
Using this method, 99% of the gold collected from the samples was returned within 24 hours, with a further 1% collected from the residue.
This modified BLEG procedure was designed to reveal the full gold content of the samples.