Golden Mile Resources has completed an extensive exploration program at its Quicksilver Nickel-Cobalt Project, including in excess of 14,000 metres of aircore, RC percussion and diamond drilling. The Company has defined a lateritic nickel-cobalt resource of 26.3 Mt @ 0.64% Ni and 0.04% Co and is progressing a high-level assessment of project feasibility.
QUICKSILVER NICKEL-COBALT PROJECT
The Quicksilver Nickel-Cobalt project is located near the town of Pingaring in the South West Mineral Field, approximately 300 km to the southeast of Perth. The project is made up of one granted exploration licence (E 70/4641) and a prospecting licence (P 70/1723) that cover an area of about 50 km2 and overlay more than 15 km of strike over interpreted ultramafic stratigraphy.
Golden Mile Resources has completed a comprehensive exploration program on the Quicksilver Project including:
Data compilation and digitisation
Surface geochemical sampling
Ground electromagnetic (EM) surveys
Aircore, reverse circulation (RC) percussion and diamond drilling
GMR has defined a lateritic nickel-cobalt mineral resource of 26.3 Mt @ 0.64% Ni and 0.04% Co (cut-off grade >0.5% Ni or >0.05% Co) incorporating 23.1 Mt @ 0.68% nickel & 0.04% cobalt at a cut-off grade of 0.5% nickel; and an additional zone of higher grade cobalt mineralisation of 3.1 Mt @ 0.35% nickel & 0.08% cobalt at a cut-off grade of 0.05% cobalt.
The estimated resource contains a total of approximately 168,500 tonnes of nickel metal and 11,300 tonnes of cobalt metal. The Company has identified several areas where further drilling has the potential to extend the known resources, particularly in the southern area where drilling is currently limited and the mineralisation is open.
The Quicksilver nickel-cobalt deposit is currently subject to scoping study-level technical and financial assessment.
The project area overlies a preserved north-south trending greenstone belt, dominated by mafic to ultramafic lithologies, enclosed within basement granitic units to the east and west. This greenstone belt is interpreted to be have been metamorphosed to amphibolite grade (a similar grade to the Southern Cross Belt to the east) and composed of a package to ultramafic to felsic volcanic rocks, typical of the southern Yilgarn.
Drilling completed by Golden Mile shows that the tenement area contains a north-south trending belt of Archaean ultramafic rock. A mafic basalt unit occurs along the west side of the ultramafic. The mafic-ultramafic package has a strike length of about 15 km and varies in width from approximately 100 metres to over 700 metres. The package is bound to both the east and west by foliated granite.
The rock units have been extensively weathered and an iron-rich laterite profile has locally developed. This laterite is preserved over the Garard’s Prospect. Elevated nickel and cobalt values are due to the mobilisation and enrichment of those metals as they are released from silicate minerals during the weathering process.
Elsewhere, the surficial geology of project area is dominated by recent sediments, including soils, sands and minor clays.
Nickel and cobalt mineralisation is hosted within the weathering profile developed over interpreted Archaean ultramafic rocks. Elevated nickel and cobalt values are due to the mobilisation and enrichment of those metals as they are released from silicate minerals during the weathering process.
As with most Western Australian nickel laterite deposits, distinct geochemical zonation occurs through the weathering profile. At Quicksilver, four horizons have been interpreted – a Mixed Zone with elevated aluminium overlies Upper Saprolite with elevated iron and low magnesium, a Lower Saprolite zone with low iron and low aluminium, and a basal Saprock zone with highly elevated magnesium.
A systematic program of aircore (AC), reverse circulation (RC) and diamond drilling has been undertaken across the Garard’s Prospect area in the southern part of the tenement.
Initially, five east-west lines of AC holes, at 400 metre spacing, were drilled with holes at 100 metre spacing along the lines. On average holes were drilled to approximately 35 metres depth. However many holes finished in silicic saprock, and mineralisation, due to a lack of penetrative power from the AC drilling rig.
This drilling was therefore followed up with a systematic program of infill and extension RC percussion drilling to test the strike length and depth extent of the mineralisation. Sixteen east-west lines of RC holes, on average at 200 metre spacing, were subsequently drilled with holes at mostly 50 metre spacing along the lines.
The average depth of the RC holes was 85 metres, however, some were drilled to 200 metres in an attempt to intersect possible sulphide mineralisation targets based on modelling of a surface EM survey. A few holes were stopped in mineralisation due to drilling issues but the majority were successfully drilled into the underlying ultramafic-mafic bedrock. The RC drilling returned a number of outstanding nickel and cobalt intercepts.
Three vertical diamond drill holes have been completed through the mineralised zone to obtain detailed density, lithological and mineralogical information through the deposit.
Mineral Resource Estimate
A maiden Mineral Resource estimate was completed for the Quicksilver Nickel-Cobalt Project by Payne Geological Services in November 2018 (refer to G88 announcement to the ASX dated 19 November 2018). The deposit has a total resource of 26.3 Mt @ 0.64% Ni and 0.04% Co (cut-off grade >0.5% Ni or >0.05% Co) incorporating 23.1 Mt @ 0.68% nickel & 0.04% cobalt at a cut-off grade of 0.5% nickel; and an additional zone of higher grade cobalt mineralisation of 3.1 Mt @ 0.35% nickel & 0.08% cobalt at a cut-off grade of 0.05% cobalt.
Nickel (Ni) and cobalt (Co) mineralisation is hosted within the weathering profile developed over interpreted Archaean ultramafic rocks, which are within a metamorphosed granite/greenstone sequence. A nickel envelope was interpreted using a 0.4% Ni cut-off. This provided a largely continuous horizon typically 20 m to 50 m in thickness. A distinct zone of cobalt enrichment is also present in the deposit. A cobalt envelope was interpreted using a 0.04% Co cut-off which defined a largely continuous blanket of mineralisation typically 5 m to 15 m in thickness. The majority of the cobalt-rich blanket occurs within the upper part of the nickel envelope however in places it extends above the nickel envelope.
The main Garard’s prospect has a strike length of 2,000 m and is up to 700 m wide. The majority of mineralisation is within 50 m of surface, with a maximum depth of 105 m. A second zone of nickel enrichment has been delineated over a strike length of 700 m at the Garard’s South prospect. This zone remains open to the south.
The deposit was delineated by Golden Mile with air core (AC), reverse circulation (RC) and diamond drilling (DD) completed in 2017 and 2018. The Mineral Resource is defined by a total of 111 drill holes for 9,048 m.
The Mineral Resources have been classified as Indicated and Inferred Mineral Resources in accordance with the JORC Code, 2012 Edition. This table represents the total deposit and is reported using a cut-off grade of > 0.5% Ni or > 0.05% Co.