Marmota (ASX: MEU) has returned increases of as much as 73% in gold grades with new test work undertaken at its Aurora Tank project in South Australia.

The company had intersected thick intervals of high-grade gold at the project’s southern area in late 2024, including a 1-metre section that returned 50 grams per tonne (g/t) gold.

Marmota collected around 23.41kg of samples for further assessment in the laboratory, which were subsequently subdivided into five 2kg samples and subjected to bulk leach extractable gold (BLEG) test work.

Substantial grade increases

Notably, all five of these BLEG samples have now returned dramatically-higher grades, with three of the assays above 90 g/t.

“Companies that are lucky enough to get such high grades are sometimes reluctant to re-test them, particularly if there is a ‘nugget effect’ that caused the high grade in the first place,” company chair Dr Colin Rose said.

“Marmota has re-tested the highest 50 g/t sample from the November 2024 [program] using the high-precision, large-sample BLEG technique—not just once, but by taking the entire sample bag and subdividing it into five fresh samples.”

“We are delighted with the verification of high grades at Aurora Tank, particularly relevant with resource modelling next to commence.”

Resource estimate confidence

While BLEG test work is a markedly more expensive way of conducting tests, the company decided to use this method to provide confidence for resource estimation with confirmation of the previous high-grade fire assay results at Aurora Tank.

This methodology also acts as a check against so-called “nugget effects”—the phenomenon where gold occurs in unevenly distributed, coarse clusters that can lead to highly variable assay results.

To date, no additional BLEG work has been carried out on other holes from the 2024 Aurora Tank drilling program.