Lefroy Exploration (ASX:LEX) high gold recoveries confirmed at Burns Gold Deposit

Lefroy Exploration has reported metallurgical test work results from the high grade zones within the Burns Gold Deposit, with test work confirming 97% gold recovery by conventional cyanide leaching from oxide and fresh rock domains at typical processing conditions.

The company also reported high gravity gold recovery ranging from 38% to 57%, with gravity and cyanide leach gold recoveries independent of copper grade.

The results will be incorporated into the re domaining of the current Burns High Grade resource wireframes, with an updated Mineral Resource Estimate for the Burns High Grade zone to be completed before the end of the September quarter.

Highlights

The Burns Gold Deposit forms part of the Lefroy Gold Project, located approximately 70km southeast of Kalgoorlie in the Kambalda Kalgoorlie gold district of Western Australia.

The Burns Central High Grade resource contains 4.22Mt at 1.18g/t Au for 159,285oz, comprising Indicated resources of 4.11Mt at 1.19g/t Au for 157,215oz and Inferred resources of 0.1Mt at 0.63g/t Au for 2,070oz.

The broader Burns Gold Deposit contains a Mineral Resource Estimate of 42.96Mt at 0.36g/t Au for 497,472oz, including Indicated resources of 32.31Mt at 0.38g/t Au for 394,308oz and Inferred resources of 10.65Mt at 0.30g/t Au for 103,165oz.

Lefroy engaged Independent Metallurgical Operations Pty Ltd to conduct metallurgical test work on representative material obtained from diamond drill core samples from LEFD010 and reverse circulation samples from LRR026 within the high grade zones of the Burns Gold Prospect.

The program was undertaken to determine the amenability of the high grade ore to conventional gravity separation and cyanide leaching processes for the recovery of gold by replicating typical conditions within cyanide leach gold processing plants in the Goldfields region.

The test work returned high gravity gold recoveries ranging from 38% to 57% across all composite samples. Composite 1 (Fresh Ore) reported a 30% increase in gold recovery from 67.4% to 96.9% with an increased NaCN concentration.

Composite 2 (Fresh Ore) achieved 97.1% total gold recovery and Composite 3 (Oxide Ore) achieved 97.9% total gold recovery at NaCN concentrations of 500/300ppm.

The company reported that gravity gold recoveries are independent of copper grade and gravity copper recovery, while gravity and cyanide leach gold recoveries are independent of copper grade.

Fresh mineralisation represents 66% of the current Burns High Grade mineral resource, oxide mineralisation represents 29%, and transitional mineralisation represents 5%.

Composite 4 (Transitional Ore) contained the highest cyanide soluble copper content, and the company stated that processing of transitional type ore will require an assessment of alternate processing options such as a combination of gravity, flotation and leach processing.

Lefroy Managing Director Graeme Gribbin said,

“Strengthened by these results, we now move with greater confidence towards providing an updated mineral resource estimate at Burns, which will guide further studies and resource growth drilling initiatives in the coming months.”

The company stated it will immediately commence the next phase at Burns.

Central to this work will be the re domaining of the mineral resource, guided by and incorporating the improved understanding of mineralogy and metallurgical domains received from the recently completed metallurgical test work.

This will culminate in the completion of an updated Mineral Resource Estimate for the Burns High Grade zone before the end of the September quarter, which the company stated will guide development studies.