Coates Project

PROJECT HIGHLIGHTS

The recent discovery of Nickel (Ni) Copper (Cu) and Platinum Group Elements (PGE) in sulphide mineralisation at Chalice Gold Mines’ Julimar project (announced in March 2020), as well as indications of other instances of similar mineralisation discovered by other explorers within the Jimperding Metamorphic Belt, serve to highlight the great potential of this geological terrain

  • Project comprises 1 granted Exploration Licence and 1 EL Application; and 1 retention licence, with a combined area of 48m2
  • Located 60km northeast of Perth
  • Covers the northern half of the Coates Mafic Intrusive
Coates Project overlain on the regional aeromagnetic image (left) and simplified geology plan (right).

EXPLORATION POTENTIAL

The coincidence of base metal and PGE geochemical anomalies from the BRL vacuum drilling with the Coates Mafic Complex is most encouraging from an exploration point of view.  By analogy the mineralisation at Chalice’s Gonneville Prospect is characterised by a similar Cu-Ni-Co-PGE elemental association with a mafic intrusive complex.

There are a number of interpreted mafic-ultramafic units that have been identified in the region, all of which show geophysical similarities with the Julimar Complex and consequently all represent targets for Cu-Ni-Co-PGE mineralisation.

PROPOSED EXPLORATION PROGRAMME AND BUDGET

Outcrop in the area is poor and interpretation of the mafic-ultramafic layered intrusive complexes is based on the regional aeromagnetic data.  Following the experience of Chalice, the targets within the interpreted mafic-ultramafic complexes are identified by airborne electromagnetic (EM) surveys then followed-up by drilling.

The land title situation in the project area contains both freehold private land and conservation areas.  Statutory approvals for ground access within the granted tenements will be necessary prior to commencing field work that involves ground disturbance activities.

Initially helicopter-borne EM surveys such as VTEM can be flown to identify targets for follow-up work.  These surveys are usually sufficiently sensitive to pinpoint anomalies to the extent that further ground-based EM is not required.  The previous analysis of bottom-of-hole vacuum drill samples has been shown to be effective and this can be extended over the project area here access has been obtained.

GEOLOGICAL SETTING

The Coates Ni-Cu-Co-PGE Project, with an area of 47.3 km2, is located in the northern part of the South West Greenstone terrane of the Yilgarn Craton.  The Project covers the Coates Mafic Complex within the Jimperding Metamorphic Belt and comprises various gneisses and banded-iron formation, interleaved with ultramafic intrusive units that have been repeatedly deformed, metamorphosed and intruded by granite.

The regional geological setting of the Coates Ni-Cu-Co-PGE Project has been highlighted by the Julimar Project being explored by Chalice.  Chalice commenced a greenfield exploration program in mid-2019 for high-grade Ni-Cu-Co-PGE mineralisation in the region and interpreted the presence of an unrecognised layered mafic-ultramafic intrusive complex at Julimar based on high resolution regional magnetics.  Follow-up exploration identified the Julimar (mafic-ultramafic layered intrusive) Complex that extends over a strike length of approximately 26 km, which has been confirmed by drilling to be highly prospective for Ni, Cu and PGEs.

RC drilling resulted in the discovery of high-grade Ni-Cu-Co-PGE mineralisation at the newly named Gonneville Intrusion.  A recent airborne EM survey identified three new large EM anomalies (Hartog, Baudin and Jansz) located north of the Gonneville Intrusion [1].

The style of sulphide mineralisation intersected consists of massive, matrix, stringer and disseminated sulphides typical of metamorphosed and structurally overprinted magmatic Ni sulphide deposits.  It is understood that the discrete high-grade Cu-Ni-Co-PGE zones typically have the following grade ranges [2]:  PGE+Au: 1- 15g/t, Ni: 0.5-3.3%, Cu: 0.4-4.5% and Co: 0.03-0.27%.

On the local scale, the Coates Mafic Complex is a magnetite gabbro intrusion into granitic rocks that hosts the Coates vanadium deposit.  Lenticular magnetite has formed at the core of the layered Coates Mafic Complex between two granitic bodies (Baxter, 1978).  The deposit was discovered 1961 and explored in the late 1970s by Garrick Agnew Pty Ltd (1971).  Mining started in 1980 only to cease operations a year later due to high silica contents limiting production.

[1]. Chalice ASX Announcement 22 September 2020.
[2] Chalice ASX Announcement 27 January 2021.

PREVIOUS EXPLORATION

Previous mineral exploration in the area has predominantly been focussed on the Coates vanadium deposit (Coates) or bauxite.  There has been very little exploration for other metals and only minor gold occurrences are located at Jimperding Hill to the north of the project area and unnamed occurrences to the southwest.

Apart from recent bauxite exploration by BRL within R570/59, the previous exploration completed over the area is not relevant to the current search for Cu-Ni-Co-PGE mineralisation.  The early previous exploration is summarised for the purpose of reporting completeness.

  • 1930’s
    Jimperding Hill
    Maynard (1997) reports that gold was first discovered in the vicinity of Jimperding Hill in the late 1890s, but mining did not take place until the 1930s. The recorded production is small at 327 ounces.
  • 1961
    Mangore (Aust) Pty Ltd
    Exploration at Coates was first undertaken in 1961
    by Mangore (Aust) Pty Ltd, a subsidiary of Union Carbide Corporation, which carried out limited drilling and metallurgical studies but abandoned the project as uneconomic.
  • 1969
    Garrick Agnew
    Garrick Agnew was granted a Ministerial Reserve in June 1969 and subsequently completed an extensive drilling programme. Previous metallurgical test results indicate that a 58% recovery of vanadium at an approximate grade of 1.4% V2O5, 3% TiO2, 67% Fe grade with 8% SiO2 is achievable from an ore assaying 0.54% V2O5, 4.75% TiO2, 25% Fe and 29% SiO2.
  • Late 1970’s
    Agnew Clough
    Coates was discovered near charcoal/pig iron producing areas outside Wundowie in the 1960s, and was subject of a failed attempt to mine it by Agnew Clough from the late 1970s when the German and Japanese-funded venture hit technical problems, rising energy costs and fierce competition internationally from rival projects. Agnew Clough was unable to reach its planned first stage target of 1600-1800 tpa, part of a plan to hit 3,000 t and 10% of the global market.  The mine closed in 1982, just two years after becoming Australia’s first vanadium producer.
  • 1960’s-1970’s
    Bauxite Exploration
    During the 1960s and 70s the area was explored for bauxite by various companies including Pacminex (1965-1986), Vam Ltd (1969-1973), Bridge Oil Ltd & Project Mining Corp Ltd (1969-1987), Alcoa of Australia Ltd & Shell Company of Australia Ltd (1971-1981) and recently by BRL. Location of previous geochemical sampling results (PGE) over a total magnetic intensity image
Location of previous geochemical sampling results (PGE) over a total magnetic intensity image

RECENT EXPLORATION

In 2011 Mercator (Paton, 2011) explored E70/2230 for vanadium, base metals and PGEs using lag sampling, focused mainly on pisolitic laterite. Orientation sampling of mineralisation adjacent to the Coates Siding vanadium deposit was applied to regional surface geochemistry and successfully located vanadium anomalies in laterites approximately 3 km east of the Coates Siding deposit. In February 2011 Mercator and BRL entered into a joint venture agreement over E70/2230 which gave BRL rights to Bauxite within the tenement [3] . In 2013 BRL completed an extensive vacuum drilling programme at two bauxite prospects, Fortuna and Fortuna North (Menzies 2014). While bauxite was being targeted at the time, 520 end-of-hole samples were also analysed for As, Cu, V, Zn, Pb, Ag by ICP techniques and Au, Pd, and Pt by fire assay on the same samples. Mercator subsequently obtained a total of 950 assay pulps from bottom of hole samples from the bauxite exploration drilling and analysed the samples using a hand-held portable XRF (Cahill, 2015). Retention licence R70/59 covers the Fortuna bauxite prospect.

Plotting the distribution of geochemical assay results show co-incident base metal anomalism (Ni, Cu, & Cr) with PGEs (Pt max 37 ppb, Pd max 53 ppb & Au max 108 ppb) along the western edge of the Coates Intrusion. The coincidence of the Cu and PGEs anomalies is significant as these elements have long been considered geochemical pathfinder elements for nickel sulphide mineralisation. The distribution of Cu, Au, Pt & Pd are shown below

[3] BRL and the rights to Bauxite were subsequently acquired by Yankuang Resources Pty Ltd.
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