Andy Well Mining Pty Ltd, a subsidiary of Meeka Metals Limited, owns 100% of all Exploration Licenses, Mining Leases and mineral rights for the Project.
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Summary:
Project scale geology consists of Archean aged high Mg Basalt units intruded by north-south striking porphyry intrusives. These are cross cut by east-west striking Proterozoic dolerite dykes. The mineralized quartz vein cross cuts the Archean units but not the Proterozoic dykes.
The Yilgarn is divided into four broad tectonic terranes; the Narryer, Youanmi, Southwest and Eastern Goldfields Superterrane. The Project is located within the northern end of the Youanmi Terrane.
Andy Well
Andy Well is located at the northernmost end of the north-north easterly trending Archaean Meekatharra- Wydgee greenstone belt, within the Youanmi Terrane. The belt comprises a succession of metamorphosed mafic to ultramafics, felsic and sedimentary rocks interpreted to belong to the Norie Group formerly Luke Creek and Mount Farmer Groups.
The Andy Well local stratigraphy is comprised of a north-northeast striking, sub-vertical (~80º) dipping, Achaean volcano-sedimentary package. The stratigraphy youngs toward the West based on sedimentary textures and immobile element geochemistry of basalts. The local package follows a general transition from a basaltic subaqueaous lava sequence at its base which becomes mafic volcaniclastic dominated before transitioning to a siliciclastic sequence of agrillites and arenites to the west of the Great Northern Highway.
The gold mineralisation at Andy Well is orogenic shear hosted, narrow high-grade quartz reefs. Economic mineralisation has so far been identified within five parallel north-northeast trending quartz reefs; Wilber, Judy North, Judy South, Suzie and Jenny.
A geochemical affinity for basalt host rock/contact is also likely to be significant for mineralisation as grade is less abundant within sheared porphyry host rock.
Vein mineralogy is predominantly quartz-calcite-chlorite+/-fuchsite associated with minor disseminated pyrite with lesser amounts of chalcopyrite, galena and sphalerite. Gold is frequently visible and finely dispersed throughout laminated, breccia and massive quartz types as well as with a lesser pyrite and other sulphides. Gold grades within veining are in general above 30g/t, whilst grades outside of veining but within the mineralised envelope are in the order of <0.3g/t Au.
Mineralised veins are interpreted petrographically as a space-filling. During flow of the hydrothermal fluid through the open structure, slivers of altered wall were scavenged into the structure, and suffered replacement to form fine-grained fuchsite + chlorite in stylolitic trails. Ongoing mild deformation caused partial recrystallisation of the vein quartz, forming finer-grained sutured mosaics.
Historical production was principally sourced from the Wilber Lode, a sub-vertical slightly west dipping laminated quartz vein commonly 0.4 to 1.5m in width with a well-developed boudinage texture. It forms an extensive and largely continuous sheet of mineralisation, which is currently defined over 600m strike and 700m down dip, remaining open at depth.
Turnberry
Turnberry is located within the Gnaweeda greenstone belt, a narrow belt of Archaean volcano-sedimentary rocks up to 10 kilometres wide in the northern half and decreasing to less than one kilometre in the south, situated at the northernmost margin between the Achaean Murchison, Southern Cross, and Yeelirrie Provinces. The belt comprises a succession of metamorphosed mafic to ultramafic, felsic and metasedimentary rocks with minor felsic to intermediate intrusives interpreted to belong to the Norie Group formerly Luke Creek within the Murchison Supergroup.
Lithologies at Turnberry are dominated by dolerites with the best section of mineralisation hosted within a magnetic quartz dolerite which forms a discrete ‘double bullseye’ aeromagnetic anomaly. The magnetic dolerite is likely to represent a fractionated portion of a layered dolerite sill with a contribution of magnetite from alteration creating the anomaly within the hinge of the folded mafic. This mineralisation style is the most well developed at Turnberry as it hosts the highest and most consistent grades and widths.
The area is covered with transported colluvium to a depth of ~10-25m and is highly weathered with a depth to fresh rock of ~100m.
Mineralisation forms a 1.7km north-northeast trending gold anomalous corridor, which is broadly defined into three zones, Turnberry South, Central and North. Mineralisation is primarily hosted where shears intersect fold hinges (saddles) and limbs of felsic lithological boundaries. Vein and shear-hosted mineralisation are also present at the mafic contact, which tends to host narrow, high-grade gold. In other areas (e.g. outside of fold hinges or lithological contacts), Au mineralisation is controlled by the orientation of steeply, dipping veins within the shear zone.
Mineralisation can often be visually indistinct owing to several styles of mineralisation being present and manifested differently depending on the lithology of the host rock. There are several unrelated shearing and veining events, however gold is usually accompanied by an increase in disseminated pyrite.
Mineralisation at Turnberry South and Turnberry North has developed within felsic volcanics and porphyries with strong pervasive sericite-pyrite alteration, which hosts broad low grade gold mineralisation and local sporadic high grades. Vein and shear mineralisation is also present at the mafic contact which tends to host narrow, high grades with occasional visible gold in RC chips.
At Turnberry Central, gold is hosted within a broad alteration zone within a quartz dolerite unit. Gold is believed to occur on the flanks of an intense silica-albite-pyrite ‘core’ surrounded by distal chlorite and epidote alteration. Gold is associated with disseminated pyrite, which occurs at a background level of around 1% in un-mineralised magnetic dolerite and increases to up to 30% within the centre of the alteration zone. Gold bearing alteration is typically associated with 3-10% disseminated pyrite with moderate chlorite-magnetite+silica alteration and can occur on either side of the core of the altered zone.
St Anne’s
St Anne’s is located centrally within the north-south trending Archaean Gnaweeda greenstone belt. At St Anne’s, the belt comprises a succession of metamorphosed mafic to ultramafic, felsic and metasedimentary rocks with minor felsic to intermediate intrusives interpreted to belong to the Norie Group, formerly Luke Creek, within the Murchison Supergroup.
The St Anne’s area is covered with transported colluvium to a depth of ~20m and is highly weathered with a depth to fresh rock of ~100 to 160m.
The local geology and stratigraphy of St Anne’s from east to west, interpreted from portable pXRF analysis and geological logging, is comprised of an ultramafic base, sediments, a fractionated mafic package including ultramafic, dolerite and basalt overlain by felsic volcaniclastics. The stratigraphy dips steeply to the east and strikes north–northeast with a stratigraphy sub-parallel foliation.
Structural interpretation suggests a broad zone of shearing trends north-northeast at St Anne’s. Several northwest-southeast structures are interpreted from geophysics to crosscut the stratigraphy and appear to off-set stratigraphy regionally and mineralisation locally.
Mineralisation at St Anne’s forms an 800m north-northeast trending gold anomalous corridor, which occurs within a broad alteration zone logged by geologists and mapped by arsenic anomalism in pXRF analysis. Mineralisation is widespread and occurs within multiple mineralised envelopes, predominantly concentrated within the mafic rocks proximal to lithology contacts.