- Gold explorer Alt Resources (ARS) has released positive results of metallurgical leach testwork for its Mt Ida and Bottle Creek projects
- The testing – compiled by Como Engineers – was conducted as part of the pre-feasibility study (PFS) for the two projects
- The samples were found to be relatively easy-milling, and gold extraction rates were generally better than 91.8 per cent after 48 hours leaching
- Further metallurgical testwork is being undertaken to refine the leaching process, and reduce the high quantity of lime used in early testing
- Ten open-pit mines are planned across the Bottle Creek and Mt Ida deposits, and designs should be finalised this week by Minecomp
- This will enable the delivery of the mining schedule for the PFS and the maiden ore reserve statement, both due later this month
- Alt Resources is in a trading halt pending the release of a further announcement. Shares last traded for 2.9 cents on 28 April
Gold explorer Alt Resources (ARS) has released positive results of metallurgical leach testwork for its Mt Ida and Bottle Creek projects.
The testing – undertaken by ALS Laboratories Perth and AMML Laboratories in Sydney, and compiled by Como Engineers – was conducted as part of the pre-feasibility studies (PFS) for the two projects.
The results are a little tardy due to the disruption of the COVID-19 pandemic, which has had the knock-on effect of delays to the PFS and maiden ore reserve statement. Those reports are now due to be released by the end on May.
The daily grind
Reverse circulation (RC) chip samples were taken from five deposits across the projects and tested for gold and silver recovery.
All samples were tested at three different grind sizes (90μm, 75μm and 45μm) and each incorporated material from different layers of the deposit, from oxide (the most weathered) to transitional and fresh (hard bedrock).
The samples were of only low to moderate strength, low to moderate hardness, and moderately abrasive, meaning the ore is relatively easy and efficient to mill for processing.
The recovery
Aside from being largely free-milling, the samples also demonstrated acceptable leach kinetics, with the exception of those from the Forrest Belle deposit, which showed significant leaching past 24 hours.
Gold extraction rates were generally better than 91.8 per cent after 48 hours, and for the most part, no deleterious elements (like arsenic or mercury) were detected. The exception again was Forrest Belle, which contained elevated levels of cyanide soluble copper, which likely contributed to the longer leaching times.
Silver recovery varied greatly between deposits, with the highest grade coming from Southwark, at 19.9 grams per tonne.
Como Engineers were responsible for the final metallurgical leach testwork report and deemed the results to be a solid platform from which to progress the PFS.
Further metallurgical testwork is being undertaken to refine the leaching process, and reduce the high quantity of lime used in early testing.
Next steps
Alt Resources will be able to progress further upon the completion of the PFS and maiden ore reserve statement, both expected in coming weeks.
Ten open-pit mines are planned across the Bottle Creek and Mt Ida deposits, and designs should be finalised this week by Minecomp – enabling the delivery of the mining schedule for the PFS and the maiden ore reserve statement.
Alt Resources CEO James Anderson says things are looking good to progress to the next phase.
“The leach recovery testwork managed by Como over the past three months is a very positive outcome for the projects PFS and financial metrics.
“It has been quite a complex process as we have optimised ten pits with the inclusion of multiple ore types and material types.”
Alt Resources CEO James Anderson
“ALS and the Como staff have done an excellent job delivering this in the time frame considering the social distancing measures and restrictions on operations in place, we are very pleased with the recovery data from the testwork carried out.”
While there’s still a long pathway to first gold, the indications so far for Bottle Creek and Mt Ida are looking positive.
Alt Resources has extended its suspension from trade pending the release of a further announcement regarding a corporate transaction. Shares last traded for 2.9 cents on 28 April.