Horizon controls a number of prospective tenements within the Coolgardie region including Rose Hill, Brilliant North and Yarmany. Together, the projects are grouped under the title of Coolgardie Regional.
Horizon acquired the Rose Hill project in late 2019 as part of the asset swap with Northern Star Resources. Rose Hill is located 0.5km southeast of Coolgardie and 35km west of Kalgoorlie-Boulder, and lies on the western margin of the Archean Norseman-Menzies Greenstone Belt.
Mineralisation is hosted within the main Rose Hill porphyry, adjacent to the hanging wall ultramafic and an eastern porphyry unit. Gold is associated with stockwork veining throughout the porphyry and disseminated within altered porphyry. The mineralised porphyry is believed to have dioritic affinities.
The current JORC 2012 resource at Rose Hill is:
0.8Mt grading 3.7g/t Au for 93,300oz
which is comprised of an open pit Mineral Resource of 0.3Mt grading 2.0g/t Au for 18,400oz at a 0.5g/t Au cut-off grade and underground Mineral Resource of 0.5Mt grading 4.6g/t Au for 74,900oz at a 2.0g/t Au cut-off grade. Importantly, 70% of the resource is in the Measured and Indicated JORC Categories.
Rose Hill has been subject to several small scale mining operations since 1898 with reported production of approximately 5,000t grading 8.3g/t Au for 1,340oz with the most recent being a small open cut in 1983.The mineralisation at Rose Hill extends to 300m and is being investigated via a feasibility study for both open pit and underground mining.
Significant true width intercepts supporting open pit mining include:
17m @ 3.08g/t Au from 0m
14m @ 4.11g/t Au from 21m
15m @ 3.46g/t Au from 22m
7m @ 7.26g/t Au from 27m
10m @ 6.28g/t Au from 28m
11m @ 8.79 g/t Au from 43m
Significant true width intercepts supporting underground mining include:
12m @ 4.81g/t Au from 37m
20m @ 8.94g/t Au from 77m
3.5m @ 10.52g/t Au from 170.5m
7.5m @ 5.40g/t Au from 242.3m
5m @ 3.66g/t Au from 281m and 5m @ 5.93g/t Au from 289.5m
3m @ 9.25g/t Au from 407m
The Brilliant North lease (M15/1204), also known as the State Battery deposit due to its close proximity to the historic Coolgardie State Battery is located 500m to the southeast of Rose Hill and 35km west of the city of Kalgoorlie-Boulder.
The Brilliant North lease partially overlies the Brilliant North project currently owned by Focus Minerals. The development of the Brilliant North project area has been impeded in the past due to fragmented ownership of the leases. Horizon are currently reviewing the development options of Brilliant North in conjunction with the feasibility study to determine the optimal pathway for this project.
Yarmany is located on the highly prospective Ida and Reptile Shear zones in close proximity to all required infrastructure, 65km west of Kalgoorlie-Boulder in Western Australia.
The project area covers a large area of greenstone belt and 100% owned by the Company, with Horizon holding a dominant position overlying the Ida and Reptile Shear zones.
Previous geochemical work completed (Delta Gold in 1992 to 2001 and others) identified numerous anomalies, many of which have yet to be followed up. The Iguana – Jamaica and Lizard gold mines along strike of the Company’s tenure were developed between 2000 and 2009 producing 68,000 ounces of gold grading 3g/t and have current resources of 201,000 ounces.
Yarmany also has multicommodity potential in addition to gold, including Nickel and Lithium. The geology at the Yarmany Project area is dominated by tholeiitic and high MgO basalts, felsic and pelitic schists after felsic volcanic rocks and/or sediments with less common lithologies including komatiitic ultramafics and granitoid intrusives, including pegmatites. The largest of these granitoids, which occur in the southern parts of Yarmany is the Silt Dam Monzogranite, interpreted to be a post-regional folding granitoid. The region has variable metamorphic grade, but generally varies between low to high amphibolite facies typical for this western part of the Kalgoorlie Terrane.
The western margin of the Yarmany project is bounded by the 500km long, northerly trending Ida Fault, a crustal scale, east dipping, listric fault extending to greater than 15 km below surface.
The Yarmany drilling campaign completed in the March Quarter was the Company’s first program at this underexplored project. The drilling was completed in two phases, namely RC and Air Core (AC) drilling. AC drilling is typically used as a lower cost alternative to RC drilling, especially during the early exploration stage while covering a larger testing area. It is, however, often limited to drilling within the softer, more weathered rocks. During the June Quarter, a further 20 RC holes for 2,637m.
The initial results confirm the nickel prospectivity of this 1.6km long magnetic ultramafic unit (talcchlorite schist). Although there are low grade laterites and clays in the Yarmany regolith, Horizon is focussed on locating nickel sulphides that could be located beneath this laterite mineralisation. Horizon notes there is very little historic, or recent drilling, targeting nickel sulphides along this or any of the other mapped ultramafics of magnetic highs within the 50km long tenure.
The bulk of the Air Core drilling was directed to locating and testing pegmatites, in particular lithium rich pegmatites. Lithium pegmatites have been well documented in this region with several nearby companies progressing their projects (refer to Red Dirt Metal Limited, Ora Banda Mining Limited and Wildcat Resources Limited websites). The pegmatite outcrop discovered in October 2021 gave Horizon a starting point as very few pegmatites had been documented at Yarmany. Drilling along two cross lines at 50m spacings confirmed the presence of multiple pegmatite dykes in a quartz-biotite schist, however most lithium results were <50ppm. Some elevated results up to 128 ppm lithium were noted and warrant further investigation. Rare, greenish crystals (2-4mm) of spodumene were also observed in the drill cuttings, but not confirmed. Further drilling and geochemistry is planned.