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The Lake Carey Gold Project Exploration
Matsa holds a ground position of ~ 620km2 at Lake Carey which is highly prospective for new gold discoveries. The Company is committed to becoming a mid-tier gold mining company. The implementation of this vision commenced with its recently completed trial mining operation at Fortitude and mining at the Red Dog deposit. Furthermore, studies are continuing into the viability of a full scale open-pit gold mine at Fortitude and the re-commencement of underground production at the Red October gold mine (Refer to previous ASX announcements).
Matsa’s discovery at Fortitude North and earlier discoveries along the Bindah Fault, provides strong support for Matsa’s belief that there are significant areas which remain under-explored despite 30 years of exploration since the discovery of Sunrise Dam in 1988.
Fortitude North Prospect
This prospect occurs along the Fortitude Fault only ~7km from the Fortitude Mine which is on the same structure.
The Fortitude North discovery is the result of follow up of anomalous gold intercepts in wide spaced legacy aircore drill holes
To date three phases of follow-up aircore and RC drilling programmes have been completed at Fortitude North which has identified gold mineralisation in weathered mafic volcanic rocks over a distance of ~2km along the Fortitude Fault. The mineralised zone is located in an area of difficult access with the northern part in sand dunes and extends to the south under a small lake. There have been a number of significant gold mineralised intersections as summarised in the diagrams. Mineralisation is overlain by up to 40m of transported lake sediments which can be seen to also contain anomalous gold values adjacent to the basement mineralisation which is thought to be the product of erosion of basement gold mineralisation.
Gold intersections include very high values up to 84.1 g/t Au, within broad mineralised intervals with a good example from recent Lake Aircore drilling as follows:
47m @ 2.55 g/t Au from 42m (18FNAC071)
incl. 8m @ 2.22 g/t Au from 42m
and 5m @ 17.7 g/t Au from 53m
incl. 1m @ 84.1 g/t Au from 53m
and 2m @ 1.10 g/t Au from 79m
The highest grades e.g. 1m @ 84.1 g/t Au in drill hole 18FNAC71 are interpreted to reflect supergene enrichment of primary mineralisation in the weathering profile.
Four of the five RC drill holes completed in July 2018, intersected gold mineralisation in variably weathered to fresh mafic volcanics and provide some insight into the nature of mineralisation at depth. Key RC results include another very broad interval of 50m @ 1.1 g/t Au from 79m which includes gold values between the detection limit of 0.01 g/t Au to a maximum value of 11.75 g/t Au and was interpreted as a variably gold mineralised and moderately east dipping zone ~ 40m thick.
Bindah Fault Prospects BE1 – BE 4
Drilling commenced in late 2016 only shortly after the Lake Carey project was acquired by Matsa and was initially focused on the Bindah Extended target area a ~6km section of the Bindah Fault zone commencing 8km NW of Matsa’s Fortitude gold mine. This area had been the focus of only very limited previous drilling because the target is mostly overlain by Lake Carey.
Drilling led to discovery of gold targets BE 1, BE 2, BE 3 and BE4 which were defined by aircore within the Bindah Fault zone is a structural and stratigraphic corridor which contains known gold mineralisation at the Bindah, Intrepid and Gallant deposits to the south and passes within 5km of the Red October gold mine and within 15km of the Sunrise Dam gold mine to the west and north respectively.
Basement gold mineralisation was intersected in wide spaced aircore lines in early 2017 in a feldspar porphyry (dacite) intrusion as summarized in the diagram below. This was followed by infill aircore drilling which defined a mineralised corridor within the BE1 intrusive body over a distance of almost 1km.
Deeply weathered mineralised porphyry is overlain by 35-60m of lake clays and comprises a massive to weakly laminated feldspar porphyry with a fine-grained quartz/feldspar matrix. The generally massive and consistent texture of this rock suggests it to be a high level felsic/intermediate intrusive body emplaced in a dilational position along the Bindah Fault. All elevated gold values >0.1 g/t Au received to date were returned from intersections containing quartz veins within variably altered and pyritic feldspar porphyry.
As noted above, intersections with >0.5 g/t Au coincide with quartz veins typically 0.01m – 0.2m thick. Quartz veins (including the visible gold bearing quartz vein described above) pass outward into hydrothermally altered and bleached feldspar porphyry with the alteration dominated by development of sericite and pyrite.
Visible Gold Observed in 17BEDD01, the first of 5 diamond drill hole completed at BE1. This first drill hole was designed to explore the extent of gold mineralisation intersected in aircore drill hole 17LCAC130, namely, 21m @ 1.82 g/t Au from 87m as shown in the diagram above
The best diamond drill assay of 0.14m @ 8.91 g/t Au, coincides with a 14cm wide laminated quartz vein containing visible gold at a drilled depth of 79m in 17BEDD01 which was the first of 5 diamond drill holes at BE 1 (MAT announcement to ASX 23rd May 2017).
The quartz vein containing visible gold in 17BEDD01, occurs in unconsolidated clays produced by deep lateritic weathering of basement rocks. Core recoveries were very poor through this zone. Only 16 metres of the 25 metre interval (75m-100m) containing the visible gold intercept, was recovered thus the actual mineralised interval may have been significantly reduced by this core loss.
Anomalous gold values at BE 2 and BE 3 are located within an area of strong hydrothermal alteration of basement rocks characterised by sericite, quartz and leucoxene. This style of alteration is commonly associated with gold mineralisation in major dolerite hosted gold deposits including the Golden Mile at Kalgoorlie.
Drilling at BE 2 returned a number of gold anomalous intercepts with a best result of 1m @ 1.46 g/t Au from 71m (17LCAC313) in deeply weathered dolerite.
Assays have continued to better define gold target BE 3 as an irregular 1.5km long NW trending zone of highly anomalous gold values in variably weathered dolerite and andesitic volcanics including 3m @ 3.62 g/t Au from 42m (17LCAC400).
Step out drilling returned a number of gold anomalous intercepts located ~2km north of BE 1 with a best result of 3m @ 2.62 g/t Au (17LCAC381) from 45m in deeply weathered intermediate volcanics. This new target BE 4, remains open to the north and further aircore drilling is required. Further anomalous intercepts have been obtained from drilling along the Bindah Fault outside the lake.