Alba Mineral Resources (AIM: Alba) is pleased to provide an update on progress made at its Clogau-St David’s Gold Mine (“Clogau” or the “Mine”) in Wales, including assay results from gold concentrates produced from the processing of 8.76 tonnes of fines material excavated from the Mine’s historic Waste Tip.
The assay results have returned gold concentrate grades of up to 1,000 g/t, with average head grades for this material of 1.7 g/t.
· Gold concentrate grades of up to 1,000 g/t have been returned following independent assaying of the 81 kg of total gold concentrates produced at the Clogau pilot processing plant from the five pits dug in January 2022 at the Waste Tip, with the average grade of the final high-grade concentrates being 503 g/t.
· An average head grade of 1.7 g/t was achieved for the material processed through the processing plant, significantly higher than the average of 0.95 g/t achieved from the initial sampling of the same pits, indicating that the sampling exercise under-represented the overall grade due to the nuggety effect of the ore.
· The successful completion of this Phase 2 programme, including the significantly higher average head grades, will enable further economic assessment of the Waste Tip to be completed.
· A positive assessment will enable Alba to proceed with a Mining Plan and formal planning application to commercially produce gold from the Waste Tip’s estimated 4,000 tonnes of fines material.
Alba’s Executive Chairman, George Frangeskides, commented:
“The Phase 2 programme at the Clogau Waste Tip has achieved strong concentrate grades of up to 1,000 g/t, with an average across the five pits of 503 g/t. What is more, the independent assaying has confirmed that the overall head grade of the fine material taken from the Waste Tip averages 1.7 g/t, which is a significant upgrade on the average grade achieved from sampling the same material prior to the processing stage. This is unsurprising given what we know about the nuggety effect of the gold at Clogau, and it bodes well for the commercial viability of mining the Waste Tip.”
The 2,833 m ² Waste Tip at Clogau comprises ore rock mined but discarded and not processed for its gold content during previous periods of mining. Following a Phase 1 sampling programme in 2021, which returned gold grades of up to 9.89 g/t with average grades of up to 4.37 g/t for the fine fractions and 3.80 g/t for the medium fractions, the Company commenced a Phase 2 programme in January 2022. Undertaken over five pits, first assay results from this second programme returned gold grades of up to 11.35 g/t (RNS 21 March 2022).
At the same time, the Company reported that 107 kg of concentrate had been produced in its pilot processing plant from the 8.76 tonnes of sub 20mm fines material collected. Note that these reported figures correspond to the wet weights. The equivalent dry weights are 81 kg of concentrate from 7.01 tonnes of sub 20mm fines.
Subsequent to the Company’s 21 March 2022 RNS, the concentrate has been processed on-site over a Wilfley shaking table for further gravimetric concentration of the gold. This exercise has helped Alba to quantify gold recovery, which provides a metric of the initial feed ore required to produce an economic operation. The upgraded gold concentrates were then sent to an independent assay laboratory for assaying.
As shown in Table 1, during the first stage of processing the highest grades in the individual processing steps were consistently found in the centrifugal concentrator material, with highly elevated gold grades also found in the sluice box material. Average centrifuge material grades were of 108 g/t prior to tabling, with final average gold concentrate grades (post tabling) averaging 503 g/t, with a high of 1,000 g/t from Pit 5.
Average gold concentrate grades of 196 g/t after tabling were also produced from the sluice box material, greatly improving the total recovery of the processing plant. Gold grades were significantly lower in the +0.8mm fraction, validating the decision to screen the concentrate before treating it over the table. The gold grades in the initial tailings produced from the processing plant had average grades of 0.83 g/t, which demonstrates the efficiency of the plant. The gold recovered from the shaking table was generally fine in nature with some larger nuggets recovered, up to ~0.5mm.
Table 1: Assay Grades from Gold Concentrates (the figures in bold and italics represent the final gold concentrates achieved from both the centrifugal concentrator and the sluice box, in each case post tabling. NS (Not Sampled) relates to the samples compromised in transit to the independent laboratory)
The data generated from this successful Phase 2 programme, which has revealed significantly higher overall head grades than were apparent from the previous sampling programme, will enable the Company to now proceed to assess the economic potential of processing all or part the Waste Tip.
A positive outcome from that assessment will lead to the development of a Mining Plan, which will feed into a formal planning application to commercially produce gold from the Waste Tip.
Updates on other Clogau Work Streams
As stated in the RNS dated 21 March 2022, the Company submitted additional data and analysis to the competent regulator, Natural Resources Wales (“NRW”), in respect of its proposal to dewater the Llechfraith Shaft at Clogau, which dewatering requires certain permits to be obtained in respect of the discharge of mine water, post-treatment, to the River Cwm-Llechen. The Company has now received feedback from NRW in respect of those revised submissions. This feedback is being considered currently and may require further data generation by the Company. The Company and its technical advisers remain confident that the Company will be successful in its bid to dewater the shaft. Further details will be advised once the Company has a better idea of the likely timeline to a formal determination.
Further to our RNS dated 11 October 2021, our aeromagnetic UAV (unmanned aerial vehicle) survey contractors, UAVE Limited, have been engaged in the process for obtaining permission to fly and have been liaising in that regard with the UK Civil Aviation Authority to establish schedules and stake holders. The process is anticipated to take 18 weeks in total, and the Company will provide a further update in due course.
This announcement contains inside information for the purposes of the UK Market Abuse Regulation and the Directors of the Company are responsible for the release of this announcement.
For further information, please visit www.albamineralresources.com or contact:
Alba Mineral Resources plc
George Frangeskides, Executive Chairman
+44 20 3950 0725
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