Anglesey Mining upbeat on metallurgical test results

The AIM-traded company sent a 340-kilogram sample to Grinding Solutions (GSL) in June, composed of material from both zones, reflecting an anticipated production blend ratio of 3.3 White Rock to 1.0 Engine Zone.

Two pre-concentration methods were employed in the test work - dense media separation (DMS) by Pesco and x-ray transmission sorting (XRT) by TOMRA.

Both methods indicated the feasibility of a successful pre-concentration stage, with the overall base-metals-only head grade rising significantly.

DMS yielded a 52% increase to 11.4% zinc equivalent, while XRT showed a 55% increase to 11.7% zinc equivalent.

Those results were expected to further improve with the inclusion of gold and silver values, which were projected to add 3% to 4% to the zinc equivalent grade.

Looking at the preliminary results, the original sample showed 3.6% zinc, 3.1% lead and 0.42% copper for a 7.5% zinc equivalent result.

The DMS results showed 6.4% zinc, 3.8% lead and 0.6% copper, and the XRT results showed 6.4% zinc, 3.7% lead and 0.7% copper.

Moreover, preliminary findings from the locked-cycle flotation test work showed higher recoveries than historical testing.

The results were based on calibrated pXRF readings, with complete wet chemistry data expected in the next two to three weeks.

Compared to the preliminary economic assessment estimates, the GSL test work indicated substantial improvements, particularly in copper and gold concentrates.

Ongoing test work included assessments on net acid generation, settling rates, and contact leaching on the tailings, with expected results in the next two to three weeks.

Additionally, GSL would conduct a diagnostic leach test on the final zinc tailings to optimise gold recovery.

“We are very pleased by the preliminary results from the metallurgical testwork on the White Rock and Engine Zones, which have demonstrated that the assumptions used in the 2021 preliminary economic assessment are potentially on the conservative side,” said chief executive officer Jo Battershill.

“The results show that the overall metal recoveries appear to be better than expected, particularly for both copper and gold.

“It is also very positive to confirm that the Parys Mountain deposit is amenable to both DMS and XRT pre-concentration methods with the potential feed grade increased by over 50%.”

Battershill said successful pre-concentration had many benefits, ranging from increased feed grade into the processing plant, lower volumes of tailings for disposal and the potential to build smaller, lower-cost processing infrastructure.

“We will now look to investigate the relevant capital and operating costs for each option to determine which is the most optimal route to move forward with in the planned pre-feasibility study.”

At 1048 GMT, shares in Anglesey Mining were up 1.26% at 1.47p.

Reporting by Josh White for Sharecast.com.