공시 • Feb 22
Thor Mining plc Provides an Update on the Alford East Copper-Gold Project, South Australia
The directors of Thor Mining Plc provided an update on the Alford East Copper-Gold Project, South Australia. Project highlights: Significant intercepts including: 21AED001 32.9m @ 0.4% Cu and 0.31g/t Au from 81.5m (ASX:THR 31.8.21), 21AED002 59.9m @ 0.3% Cu from 21.9m, 21AED003 32.4m @ 0.2% Cu from 15m, 21AED004 55.9m @ 0.53% Cu from 7m, including, 11.7m @ 1.0% Cu from 17.3m including, 5.7m @ 1.23% and 0.16g/t Au from 17.3; 21AED005 72.7m @ 1.0% Cu and 0.19g/t Au from 6.3m, including; 18.2m @ 2.0% Cu and 0.34g/t Au from 15.8m, A robust 3D geological model generated from recent drilling data highlights key structural and lithological controls on mineralisation and potential high-grade target zones. Initial hydrometallurgy trialling of an environmentally friendly glycine lixiviant shows positive gold and copper recovery. Phase two diamond drilling program is being designed, including continuing hydrogeology and hydrometallurgical studies. The Alford East Copper-Gold Project is located on EL6529, where Thor is earning up to 80% interest from unlisted Australian explorer Spencer Metals Pty Ltd, covering portions of EL6255 and EL6529. The Alford East Project covers the northern extension of the Alford Copper Belt, located on the Yorke Peninsula, SA. The Alford Copper Belt is a semi coherent zone of copper-gold oxide mineralisation, within a structurally controlled, north-south corridor consisting of deeply kaolinised and oxidised troughs within metamorphic units on the edge of the Tickera Granite, Gawler Craton, SA. Utilising historic drill hole information, Thor completed an inferred Mineral Resource Estimate (MRE): 125.6Mt @ 0.14% Cu containing 177,000t of contained copper; 71, 500oz of contained gold. Based on the recent diamond drilling, a new robust 3D geological model was generated using a combination of weathering, lithology, assay and structural data from logging, and regional geology, structural and geophysics (magnetics and gravity) data. Key geological outcomes: The best oxide mineralisation seems to occur where a fault has facilitated a more deeply weathered profile; Some faults appear to have had minor vertical offset on them post-development of the weathering profile; (for example, the north-east trending Netherleigh Park Fault, central to the project area). Mineralisation shows a preference to metasediments. A Sulphidic-Magnetic-Shale (SMS) stratigraphic-alteration unit, appears as a marker unit in the regional and more local magnetics images, as well as in the regional 3D magnetics and gravity inversions. The SMS unit was modelled using the information above, showing an overall synformal shape with AE3 sitting in the core or trough of overlying metasediments formed by the synform. Most supergene mineralisation appears to occur in the hanging wall of the SMS, whilst the weathered primary mineralisation (such as in the deeper sections of AE8 and AE5) appears to be associated with major faults, such as the central Netherleigh Park Fault. Thor's objective is to identify an in-situ recovery pathway ideally for both the copper and gold mineralisation at the Alford East Project that is socially and environmentally friendly rather than using conventional acid in-situ recovery (ISR). This has led to Thor engaging Mining Processing Solutions (MPS) trialling their alkaline Glycine Leaching Technology (GLT), branded as their GlyCatTM and GlyLeachTM processes, that have the capability to selectively leach base and precious metals using glycine as the principal, eco-friendly, reagent. A preliminary `Discovery' metallurgical test program has been carried out to determine the amenability of the Alford East mineralisation to metal recovery using GLT. The test work has involved two rounds of Diagnostic Leach Tests (DLTs), and one round of Bottle Roll Tests (BRTs) (Figure 8) on the two samples from 21AED001. The two zones are highlighted in Figure 6. Ground water collected from Alford East was used in the laboratory test work to ensure water characteristic especially pH were tailored to Project conditions. Initial Findings: Based on copper sequential analysis (identifies leachable copper mineralogy) - 15% of the copper from the upper zone and up to 50% from the lower zone should be theoretically leachable with GLT. Based on the gold diagnostic leach assays, extraction from the lower zone of up to 73.4% should be theoretically leachable with GLT. Upper zone had negligible gold. Diagnostic Leach test- designed to be initial comparison tests to ascertain the response to a range of conditions including a baseline cyanidation test. Bottle Roll tests (6): The composite sample performed very well with GLT, extracting 98.1% of the gold and over 40% of the copper. Lower zone using GLT extracting 78.3% of the gold and 33.5% of the copper, whilst the Lower zone using cyanide extracted 64.1% Au and 48.2% of the copper. The alkaline Glycine Leaching Technology (GLT) has slower leaching dynamics, than cyanidation, so if given more time higher extractions would be expected. Next Step: Based on the new geological model, approximately 10 diamond drill holes have been designed to test potential high-grade zones: Along strike and up-dip of deeply weathered zones, Targeting controlling key structures including the Netherleigh Park Fault at depth especially where there are large gaps in existing data, Targeting intersection of SMS and Liaway offset Fault, Targeting intersection of Netherleigh Park Fault and Liaway Fault Targeting subordinate splays off Netherleigh Park Fault where there is evidence of a deep weathering trough. In addition, hydrogeological water bores and pump testing is in planning to determine aquifer connectivity between holes, with initial focus in the northern area of the mineralisation. Concurrent to drilling, hydrometallurgical work will continue to investigate and optimise both copper and gold metal extraction using environmentally friendly lixiviants.
