Mincor has embarked on an exciting new chapter as it prepares to restart nickel sulphide mining in the Kambalda district of WA, one of the world’s great nickel provinces.
Since its discovery by WMC Resources Limited in 1966, it has produced more than 51mt of ore grading 3.1% Ni for 1.6mt of nickel metal.
Mincor played a leading role in Kambalda’s post-2001 revival, with the company producing about 180,000t of nickel metal in ore over a successful 14-year period as a profitable, dividend-paying mining company before placing operations on care and maintenance in 2016 at a time of historically low nickel prices.
The company has a dominant ground position in the Kambalda District with tenements covering more than 300km2 and a large, high quality Mineral Resource inventory totalling 5.0Mt at 3.8% Ni for 187,800t of contained nickel, including ore reserves of 2.3mt at 2.8% Ni for 65,400t of contained nickel.
Mincor’s nickel portfolio includes the full spectrum of assets ranging from the first greenfields discovery in Kambalda (Cassini) to existing mines on care and maintenance, to brownfields extensions and exploration targets.
A Definitive Feasibility Study (DFS) completed in March 2020 for the company’s integrated mine restart plan confirmed an economically robust project with low start-up capital requirements, a pre-tax IRR of 98% and low unit cash costs.
The DFS outlined an initial five-year mining operation delivering 71kt of nickel-in-ore and 5kt of copper-in-ore.
The restart plan is underpinned by an Ore Tolling and Offtake Purchase Agreement with BHP Nickel West to utilise the nearby Kambalda Nickel Concentrator and will sell nickel concentrate to BHP Nickel West.
Nickel exploration
As part of Mincor’s Nickel Restart Strategy, the company has a long-term commitment to exploration to grow its high grade nickel Mineral Resources and Ore Reserves.
The miner has consolidated nearly all of the shallow prospective nickel ground within the Kambalda district, and has a strategic footprint with a history of delivering profitable high-grade nickel mines.
There has been limited greenfields exploration in Kambalda over the past 20 years, with most operators focusing on near mine and brownfields exploration.
The key setting for all Kambalda nickel mines is the basal contact between an ultramafic rock hosting nickel mineralisation and the underlying basalt rock. Geologists are looking for the ancient ultramafic lava channels that flowed over the basalt surface.
It is at the base of these channels where economic nickel sulphide mineralisation can potentially accumulate.
Mincor’s nickel exploration program is progressing multiple targets within its highly prospective portfolio.
Much of the nickel produced from the district came from a few very large (>100,000t) nickel mines, all of which are located around the Kambalda Dome.
Mincor’s North Kambalda landholding covers the northern third of the Dome, with nickel production from seven known ore systems including Otter Juan, the single biggest producer in the district.
Among the many known targets, the area east of Otter Juan and down dip of Durkin North stands as one of the most exciting nickel exploration opportunities in the company’s portfolio.
Mincor has confirmed the likely presence of the mineralised channel structure in drilling down dip of the Otter Juan and along plunge of the Long channel structures.
As part of the DFS, a 1.1km incline is planned to be developed between Long and Otter Juan mines. This provides an ideal opportunity to drill into a large area which remains completely untested.
Historically, this area has not been drilled from surface and was difficult to access from underground due to a tenement boundary split between IGO and Mincor which no longer exists.
The channel is well defined and underground drilling targeting the untested space between Durkin North and Long has high potential to provide nickel intersections to increase current or add new Mineral Resources.
The Widgiemooltha Dome area is home to the Cassini deposit, a blind near-surface nickel sulphide discovery made by Mincor in 2015.
Cassini offers excellent potential by extending the existing Resource area and progressing other greenfields targets in the surrounding area.
The Cassini deposit shares many key geological characteristics with some of the larger nickel mines elsewhere in the regionh, with these characteristics known to generate extensive and multiple mineralised channel trends.
Two open-ended Resource trends have been delineated at Cassini to date (CS2 and CS4), with promising intersections also returned in adjacent channel trends. The combination of these channels demonstrates the opportunity to rapidly build substantial high-grade nickel Resources.
In early 2020, Mincor re-commenced drilling a target adjacent to Cassini, at Cassini North. Economic grade intersections had previously been reported from this area and interpreted channel structures at Cassini North bear a strong resemblance to the Cassini Mineral Resource.
Within the greater Cassini area, exploration targets at Juno 4 are continuing to be assessed by the Mincor exploration team using Mincor’s proven exploration methodology.
The Bluebush line has two nickel Mineral Resources, Stockwell and Cameron, on the western side of the Bluebush anticline.
Republican Hill lies at the southern end of the Bluebush group of tenements, with the prospect located within a large ultramafic body adjacent to the basalt contacts and contains numerous small nickeliferous gossans mapped at the surface.
The fertility of the ultramafic was confirmed in historical drilling campaigns which intersected nickel sulphides.
Field inspections indicate that a 2km strike length of this highly prospective basal contact remains untested by drilling.
Miitel was Mincor’s first nickel mine, purchased from WMC as part of a joint venture in 2000.
Mincor has owned 100% of Miitel since 2003. Historical production from Miitel between 2000 and 2016 totalled 2.5mt of ore at 2.9% Ni for 72,000t of contained nickel.
The mine was placed on care and maintenance in February 2016 following a prolonged period of low nickel prices.
The DFS mine plan involves dewatering and rehabilitation of the mine prior to the commencement of underground extraction of the South Miitel and Burnett deposits, accessing the orebodies through the existing Miitel portal and workings to extract 0.4Mt of ore at a nickel grade of 2.5%.
Other metals
The Widgiemooltha Gold Project is located within the Widgiemooltha Dome, surrounded by a number of prolific gold camps including St Ives (>15moz), Higginsville (>2moz), Chalice (600,000oz) and Wattle Dam (260,000oz).
The WGP was developed as an important gold option for the company, enabling Mincor to respond to the 2016 nickel price downturn by refocusing on the significant gold potential of its Kambalda tenement holding.
Successful drilling programs resulted in the establishment of a gold Mineral Resources base of 4.3mt at 2.0g/t Au for 273,600oz.
A Feasibility Study completed in 2018 confirmed the economic viability of a low capital start up gold mining operation based on the extraction of shallow reserves across 10 open pits.
Gold production commenced in July 2018 under an ore tolling agreement with Westgold Resources Ltd.
The gold operations ceased in line with the operating plan in the December 2019 quarter
With the Company’s focus now returned to nickel exploration and development programs, Mincor is considering strategic options to realise value from the WGP.
The Tottenham Copper-Gold Project is located in the Lachlan Fold Belt of NSW in a geological setting similar to that of the Girilambone group of mines, including the Murrawombie (formerly Girilambone) and Tritton copper mines operated by Straits Resources (located approximately 120 km north-northwest).
Mincor’s Tottenham ground holdings include two copper resource level projects at Carolina and Mount Royal, which host a combined Mineral Resource estimate of 7mt @ 1.2% Cu and 0.4g/t Au for 86.1kt of contained copper and 90.6koz of contained gold.
Exploration of the Tottenham Project is being undertaken by Bacchus Resources Pty Ltd as part of the Tottenham Earn-In and Joint Venture.
Bacchus holds a current 19.88% interest in the Tottenham tenements, with the right to increase its interest to a maximum of 30%.
