Apollo Minerals Ltd (ASX:AON) has further enhanced the world-class potential of its Kroussou Project in Gabon with metallurgical tests returning zinc and lead recoveries and concentrate grades described as exceptional.
Test-work on representative samples from the province-scale project was carried out by Independent Metallurgical Operations (IMO).
Flotation tests demonstrated zinc recovery into a saleable concentrate of 93% and lead recovery into a saleable concentrate of 64.4%, demonstrating top-tier world-class recoveries.
In upper band for recoveries
Benchmarking the recovery results to comparable global zinc and lead producers place Kroussou in the upper band of zinc and lead mines when classed by metal recoveries.
The IMO tests also produced a zinc concentrate grade of 53% zinc and a lead concentrate grade of 70% lead and benchmarking these results to major zinc and lead producers indicates a high-quality concentrate product with a highly desirable grade profile.
“Provides further confidence”
Apollo Minerals’ managing director Neil Inwood is delighted with the excellent results: “Confirmation we have identified a simple processing pathway for Kroussou mineralisation with extremely strong recoveries of contained metal into clean saleable zinc and lead concentrates provides further confidence in the world-class development potential of the project.
“The Kroussou metallurgy results compare favourably with the recoveries and concentrate grades of current zinc and lead producers and are on the upper end of globally accepted benchmarks.”
Aim of test program
IMO's test-work program was designed to define and quantify the characteristics of potential saleable concentrates from representative samples taken from Kroussou.
Mineralisation utilised for the test-work was taken from diamond drill core from drilling conducted at TP11 in 2021.
This core was chosen to be representative of the known geology and to allow for determination of both the zinc and lead flotation characteristics.
The master composite sample utilised for the tests was taken from four diamond drill holes with a head assay grade of 2.06% zinc, 2.61% lead and 0.8ppm silver.
The test-work included grind optimisation of the master composite sample followed by reagent optimisation flotation tests to define the overall optimised flow sheet. This has resulted in the production of high recovery and high-grade concentrates.
The test program also involved significant detailed flotation and comminution test work to assist in the development of process flow sheet for future technical studies.
Recoveries are key
Given metal recoveries is a key determinant of project viability the results further reinforce the world-class potential of the mineralisation at the province-scale Kroussou Project.
IMO provided the following comments on the results:
- The SMC test-work on the master composite showed the mineralisation is relatively soft with respect to breakage of material for crusher design, indicating low-cost SAG milling and crushing potential.
- Bond Ball Work Index (BBWi) test (16.8wkh/t) showed the mineralisation is hard and is suitable for standard SAG milling.
- The ore is categorised as mildly abrasive which is favourable and in the common range for base metal deposits.
Lock cycle flotation tests have not yet been completed due to the high recoveries and grades of both lead and zinc.
Lock cycle test-work and other repetitive batch flotation tests will be conducted as part of future detailed metallurgical test-work phases when feasibility studies are advanced.
Works program
Analysis of regional drilling and exploration recently completed at TP13, TP8 and TP24 is ongoing.
A comprehensive regional airborne electromagnetic (AEM) survey has been completed over the entire 80-kilometre strike length of the Kroussou permit with results being interpreted and analysed for target generation in conjunction with AON's extensive geochemical and geological data sets.
Interpretation work will also focus on identifying potential high-grade structural targets as seen at Niambokamba (TP13) as well as embayment-style targets as seen at Dikaki (TP11).
The AEM survey, combined with results from the regional passive seismic program and analysis and interpretation of all exploration and drilling results received to date, are being interpreted with the intention of defining an exploration target for Kroussou consistent with the JORC Code 2012.
“We are looking forward to defining a JORC-compliant exploration target for Kroussou which we believe, in combination with excellent metallurgy, the near-surface open-pittable nature of the identified mineralisation and the clear logistical pathway to market, will demonstrate the global significance of Kroussou as a future strategic base metal producer,” Inwood added.