Classic Minerals reports 6.06g/t gold in first bulk sample testing of Kat Gap ore
Classic Minerals considers the bulk sampling results “very encouraging” for future open pit mining operations.
Assay results from the testing of bulk sample ore at the Gekko pilot plant for Classic Minerals’ (ASX: CLZ) Kat Gap project in Western Australia have confirmed an average head grade of 6.06 grams per tonne.
Testing assayed approximately 90g/t gold, with a tailings grade of 1.62g/t to produce the overall head grade, which is believed to be 16% higher than the predicted block model.
Gravity recovery was in line with expectations and was recorded at 73.2% into a mass pull of 4.6% of the feed.
The ore material put through the Gekko test run was sourced from the base of the bulk sample pit at Kat Gap, which had an average resource block model grade of 5.12g/t gold.
The results are believed to be “very encouraging” for future open pit mining operations.
Quartz content
The concentrate contained crushed material with a top size of 2.5 millimetres, which was predominantly quartz with minor fractions of iron oxide and other minerals.
Gold was present as freely liberated (38% of the total concentrate) and binary gold/gangue particles.
A base metal scan is currently underway to determine the exact metals present in the concentrate.
The figures are believed to compare well against previous bench-scale metallurgical testwork results of between 65% and 75% at a mass pull of 5%.
High-grade concentrate
The pilot testwork has demonstrated the Gekko flowsheet is capable of concentrating ore to produce a high-grade concentrate, while discarding a proportion of the gold into a low-grade tailings stream.
It also showed the plant is capable of extracting high levels of gravity gold from Kat Gap at relatively low cost with no chemical reagents.
It is believed to have increased Classic’s confidence of the viability of the milling process.
“By controlling the mass pull to an optimal value, the project financials may be maximised based on the gold price, and ore feed grade and three configurations may be entertained with the current plant flowsheet,” the company said.
“The Gekko plant offers a versatile processing which will allow us to optimise recovery at Kat Gap depending on market conditions, ore competency, ore grade and gold price.”