Gateway Mining Limited (ASX: GML) announced that drilling has intersected multiple stacked lodes with grades of up to 17.4g/t below the existing lodes within its Gidgee Gold Project in Western Australia, and highlighted the potential to expand the current 120koz Resource.
The company said that several in-fill and extensional Reverse Circulation holes drilled at the 120,000oz Montague-Boulder Mineral Resource intersected multiple stacked mineralised shear zones. GML said that these multiple stacked lodes are consistent with Gateway’s emerging interpretation of the geology along the highly prospective Northwest Margin of the Montague Granodiorite Dome.
Significant intersections from these multiple lodes include 5 metres @ 17.4g/t Au from 83m; 5 metres @ 2.7g/t Au from 115m; and 2 metres @ 5.6g/t Au from 178m.
The company said that the follow-up drilling at the deeper Gordon’s Lode, discovered last year, successfully intersected a well-defined mineralised structure. Significant hits included 2 metres @ 3.0g/t Au from 235m; and 2 metres @ 2.1g/t Au from 240m. GML noted that this new Gordon’s Lode intersection is located 40m down-dip of the previously reported discovery intercept in GRC330, substantially expanding the potential of this new structure.
The company said that these lower repeat lodes are not included in the current Montague-Boulder Mineral Resource estimate (with the exception of Gordon’s Lode), and highlight the potential to increase the Mineral Resource within the existing footprint.
GML said that these results form part of the ongoing flow of results from the significant RC drilling program completed during October and November 2020, and does not include the holes drilled to further evaluate the recently announced Northwest Margin Lower Zone discovery, which were drilled at the completion of this in-fill program and for which assays are still awaited.
The Gidgee Gold Project is located in the Gidgee district in the Archean Yilgarn Craton of Western Australia approximately 630km NE of Perth and 70km north from the township of Sandstone on the eastern central portion of the Gum Creek Greenstone Belt, of the Southern Cross Province.
Significant targets within the Gidgee project include Kashmir, Mafic Shear Zone, Whistler, Achilles, Stockwork, Montague-Boulder, and Airport. Kashmir is 1.8km long gold-in soil anomaly.
Drilling at Gidgee project
Gateway Mining had recently commenced Resource in-fill and extensional Reverse Circulation (RC) program at the Gidgee project. Drilling was undertaken beneath the Montague-Boulder inferred mineral resource to infill the existing mineral resource area and test for potential repeats of mineralisation.
The overall program consisted of 47 holes for 5,239m, with holes drilled to systematically in-fill the existing Mineral Resource area on nominal 40m x 40m spacing. The company said that several holes were extended to test for potential repeats of the mineralisation below the interpreted Resource structures. Further results from this program are still outstanding.
GML said that several key sections of the Montague Mineral Resource area were selected for deeper drilling, to test for potential additional mineralised structures below the existing structures defined in the current Mineral Resource estimate.
The company announced that new structures below the mafic volcanic hosted shear zone lodes were intersected at depth, with several high-grade intersections returned including GRC599: 5 metres @ 17.4g/t Au from 83m; GRC603: 2 metres @ 5.6g/t Au from 178m.
GML said that these mineralised shears appeared to be parallel to the overall mafic stratigraphy, with the mineralisation associated with biotite alteration and sporadic quartz veining, and trace sulphides (pyrite). The company said that the intersection in GRC603 is interpreted to represent an up-dip position of Gordon’s Lode, intersected 140m further north.
Results from follow-up drilling
The company said that the follow-up drilling targeting the previously discovered Gordon’s Lode mineralisation (GRC330: 4 metres @ 24g/t Au from 241m2) was successful in intersecting a visually discrete mineralised structure 40m down-dip from the high-grade intercept in GRC330. The company said that this structure was mineralised, and opens up the potential for this lower lode to be further extended both along strike and down-dip.
Significant hits included GRC596: 2 metres @ 3.0g/t Au from 235m, and 2 metres @ 2.1g/t Au from 240m.
GML said that the drilling to test below the shallow granodiorite-hosted mineralisation mined as part of the historical open pit mining campaign successfully intersected what appears to be a new zone of granodiorite-hosted mineralisation. Intercepts included GRC583: 5 metres @ 2.7g/t Au from 115m.
The company said that the mineralisation at depth within the granodiorite has essentially not been previously tested, and provides a significant new exploration target as well as a possible vector to a related mafic volcanic hosted shear.
GML said that all of these multiple mineralised lodes are interpreted to form part of an overall highly-mineralised structural regime immediately adjacent to the contact of the Montague Granodiorite Dome.
Potential for significant additional mineralisation
The company said that the potential for additional structures within both the main mafic volcanic host-rock sequence, as well as within the Montague Granodiorite body itself was recognised as a result of Gateway’s systematic evaluation of the existing known mineralisation along the Northwest margin of the Granodiorite Dome.
GML said that while these holes only represent initial testing of the host sequences below the existing Resource, they do highlight the potential for significant additional mineralisation to be defined within the footprint of the existing Mineral Resource estimate.
Updates and next steps
The company said that the drilling is part of an overall infill RC program designed to upgrade confidence in the Montague Boulder Mineral Resource, and upon receipt of all samples, this Resource will be re-estimated.
GML said that further assay results are pending from the overall in-fill RC drilling program at the Montague-Boulder Resource area. The company said that results are also pending from follow-up drilling completed on the Northwest Margin lower zone. These holes were drilled in the final week of the Company’s 2020 drilling campaign, with assays expected in late December 2020/early January 2021.
Gateway’s Managing Director Peter Langworthy, said: “We completed an extensive in-fill drilling program at Montague-Boulder towards the end of our 2020 campaign aimed at upgrading the existing Inferred Resource at this cornerstone deposit. While a large number of results from this program are still outstanding, we have received significant results from a number of holes specifically designed to target the potential for additional mineralised structures below the existing 120,000oz Resource envelope.
The results of this drilling have been outstanding, showing that these holes intersected multiple stacked high-grade lodes outside the current Resource – a fantastic result. This has reinforced the potential both to increase the size of the Montague Resource while also upgrading the resource classification.
This is another clear indication of the enormous exploration upside at the Gidgee Project, both at our known deposits and more broadly across the project area. We are looking forward to receiving the balance of the results from our 2020 drilling, which should give us strong momentum moving into the resumption of exploration next year.”