The directors of Thor Mining Plc (“Thor”) (AIM, ASX: THR) are pleased to advise of the identification of a number of significant magnetic targets following the interpretation, of the Airborne magnetics survey flown in October 2020, at the 100% owned Ragged Range Project in Western Australia.
· Sterling Prospect, identified as the principle initial target, is approximately five kilometres long & between 300 and 500 metres in width;
· Anomalous stream sediment gold assays (up to 2.2g/t Au) clearly related to the structural contact of the Euro Basalt and younger Dalton Suite, at the Sterling Prospect. Gold present in streams confirms that gold mineralisation occurs very close to surface. (ASX/AIM: THR 1 December 2020);
· Three isolated, strong magnetic anomalies, highlighted on the geological maps with links below, have no simple geological explanation in the magnetics. These are priority targets for follow-up;
· The Ragged Range area is structurally complex with many phases of folding and shortening of the prospective Euro Basalt. This leads to the creation of space, significantly increasing the potential to host gold mineralisation.
Mick Billing, Executive Chairman of Thor Mining, commented:
” It is very exciting to see the interpretation of airborne magnetic data helping to explain the occurrence of, what appears to be, significant gold mineralisation at the Sterling Prospect, at Ragged Range.”
“The Sterling Prospect appears to be a target of some substance, with a strike length of up to five kilometres and multiple anomalous stream sediment gold assays. Next steps will consist of detailed soil sampling over this, with reconnaissance soil sampling over the other shallow magnetic anomalies.”
“The simple thrust model for quartz-carbonate veins hosting significant gold mineralisation at the Sterling Prospect makes a compelling target for drilling early in 2021 (www.thormining.com/sites/thormining/media/maps/x-sect-sterling-prospect.jpg ).”
Ragged Range Project, located in the highly prospective Eastern Pilbara Craton, WA is 100% owned by Thor Mining – E46/1190, E46/1262, E46/1355 (application), with the recent acquisition of additional tenure surrounding the gold anomalous zones, E46/1340 and E46/1354 (application).
Further to the announcement of 6 October 2020, the high-resolution airborne magnetics survey was flown by MAGSPEC Airborne Surveys Pty Ltd on close spaced 40m traverses, totalling 3,088-line kilometres. The flight lines were oriented perpendicular (0450) to prospective stratigraphic and structural controls in the project area. The survey was flown over E46/1190, E26/1262 and E46/1355 with the recently purchased Greatland Gold PLC airborne magnetics data ‘stitched’ into the raw data set.
Detailed Geological Interpretation
The following information is taken from the Geological Survey of Western Australia (GSWA), Split Rock 1:100,000 geology notes:
Corunna Downs Batholith Is a large granitoid body (Intruded around 3000Ma). On the geological map (accessed from the Thor website via links below) it is coloured pink.
Running NNE across the magnetic images are a series of dykes. These dykes are post Euro Basalt but pre the major thrust zone. They have a high K response suggesting they could be felsic rather than mafic. On the geological map they are coloured light green.
The Gorge Creek Group (~2950Ma) crops out in the centre of two narrow N/S striking synclines. It is a mixed sedimentary/banded iron-formation, unit. On the geological map it is coloured blue.
The Dalton Suite (3070-3060Ma) is an ultramafic unit with pyroxene-hornblende gabbro, metadunite, metaperidotite, serpentinite and minor komatiite. It has a very strong magnetic response, using all magnetic filters. On the geological map it is coloured dark blue, dark green and purple.
The Euro Basalt is overlain by the Wyman Formation (3325-3315Ma), a more felsic unit with felsic volcanics and interlayered sandstone, minor ironstone, chert and felsic schist. This unit has a uniform, low magnetic response in the 1VD. On the geological map it is coloured light orange.
The oldest unit on the map sheet is the prospective Euro Basalt (3335-3350Ma); predominantly a tholeiitic basalt with pillow lavas and minor komatiitic basalt, schist, chert and amphibolite. It has distinctive stippled magnetic response and major folds can be easily traced in the 1VD. On the geological map it is coloured medium green.
The initial airborne magnetic interpretation was completed using a 1st vertical derivative (1VD) of the data to enhance shallow, structural features. This was overlain on a simplified GSWA 1:100k geological map. Structural features such as an interpreted thrust, major faults and geological boundaries can then be interpreted and plotted. Other images using different geophysical filters along with the radiometric data were also investigated. Onto these images a thematic map of the stream sediment sample results has then been plotted to show the geological location of the anomalies.
A simplified cross section ( www.thormining.com/sites/thormining/media/maps/x-sect-sterling-prospect.jpg ) over a slice of the area (shown as A-B on the geological maps) that illustrates a simplified structural model for gold mineralisation at the Sterling Prospect. The Sterling Prospect is about five kilometres long and around 300m to 500m wide. Gold values increase upstream in both the BLEG and < 2mm, AR25 stream sediments, towards the contact. Interestingly, Thor reports no anomalous gold in streams to the west of this contact, in the ultramafic Dalton Suite. This model is preliminary, providing an explanation for the location of the stream sediment gold anomalies, close to the Euro Basalt and Dalton Suite contact. In the hanging wall (Eastern Side) of the thrust, space will be created during thrusting, allowing quartz veining to form, potentially with gold mineralisation. This preliminary model will certainly improve once drilling commences at the Sterling Prospect.
Three circles are shown covering magnetic anomalies seen in the 1VD magnetic image (geological maps). These do not appear to have any reasonable geological explanation. They are also shown on the geological map image image that uses an Analytic Signal of the Vertical Integral (ASVI) filter. ASVI is a processing method for potential-field data, also called the total gradient method. It is used for defining the location and depth of edges of magnetic anomalies. In this image, the anomalies are quite distinct and will be investigated at the earliest opportunity.
The nickel gossan reported in ASX: (26 Aug 2020) and (6 Oct 2020), is located towards the base of the Dalton Suite, close to the Wyman Formation. Follow-up soil sampling will target the weak magnetic anomalies that extend beyond the outcropping gossan. https://www.thormining.com/sites/thormining/media/pdf/asx-announcements/20200826-pilbara-goldfields-encouraging-nickel-assay-results.pdf
The information contained within this announcement is deemed to constitute inside information as stipulated under the Market Abuse Regulations (EU) No. 596/2014. Upon the publication of this announcement, this inside information is now considered to be in the public domain.
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