The Prieska Copper-Zinc Project (Prieska Project) is the centrepiece of Orion’s asset portfolio. Historically mined between the 1970s and 1990s, Prieska is one of the world’s Top-30 volcanogenic massive sulphide (VMS) base metal deposits, with a recorded historical production of over 430k tonnes of copper and 1Mt of zinc from 46.8Mt of sulphide ore milled.

Orion is currently investigating the feasibility of developing a new mine in the footprint of the historical Prieska Mine, using the extensive remaining infrastructure, with the intent of extracting the unmined copper-zinc mineralisation from the Prieska Deposit.

Location and Infrastructure

The Prieska Project is located in the Northern Cape Province of South Africa, 270km south-west of the regional capital Kimberley. Importantly, the project has access to significant local and regional infrastructure, with key infrastructure including:

  • Sealed access roads to project site
  • 48km via bitumen road to existing rail siding
  • Four high-voltage regional lines linked to the national electricity grid
  • 175MW operational solar power plants in the area – with an additional 675MW approved and a further 300MW pending authorisation
  • 800km rail link to a major, bulk commodity and deep-water ports at Coega and Saldanha Bay
  • Bulk water pipeline supplies site from Orange River with all year pumping capacity
  • Good contractor accommodation available in the private village of Copperton, ~3km from project site
  • Low environmental sensitivity – existing disturbed/rehabilitated mine footprint


The Prieska Project contains a globally significant VMS resource totalling 30.49Mt at 1.2% Cu and 3.7% Zn including Indicated Mineral Resources of 19.13Mt @ 1.18% Cu and 3.59% Zn (refer ASX release 15 January 2019). The Resources remain open with both strike extensions and up-folded limb extensions identified by downhole geophysics.

Development Strategy

Orion is focusing on the development of the Deep Sulphide Resource, currently comprising 28.73Mt @ 1.2% Cu and 3.8% Zn, which underpinned a highly successful Phase 1 Scoping Study completed in December 2018.

The Scoping Study outlined a robust initial 10-year mining scenario based on the extraction of the Deep Sulphide Resource with processing through a new 2.4Mtpa on-site concentrator producing ~20-24ktpa of copper and 70-80ktpa of zinc in concentrates.

The Scoping Study forecast globally competitive capital and operating costs, strong operating margins and outstanding financial returns (refer ASX release 19 December 2018).

The project has well-understood metallurgy, with 20 years of processing plant operation.

Underground access has been re-established, allowing assessment of geotechnical conditions and the substantial remaining underground infrastructure. Ground conditions and infrastructure in the underground mine are generally good, and Orion is confident that mine refurbishment will not require substantial engineering effort.

A Bankable Feasibility Study (BFS) on the Prieska Project commenced in July 2017 and completed in Q2 2019, paving the way for a final investment decision in H2 2019 and commencement of construction in late 2019/early 2020 (refer ASX release 26 June 2019).

In parallel with the BFS, Orion Minerals has been progressing key commercial work streams including concentrate marketing, project financing as well as key environmental impact assessment studies and permitting.

Resource extension drilling will continue to trace the strike extensions and up-folded limb of the main Prieska VMS lens, which remains open, once access to underground drilling platform is re-established.

Near-Mine Exploration

Orion sees the potential to define a major new VMS camp in the region surrounding the Prieska deposit, with near-mine exploration programs delivering a series of compelling new targets.

These include the emerging Ayoba VMS discovery, 5.3km south west of Prieska, where the discovery drill hole intersected 9.5m of massive sulphides grading 0.63% Cu and 0.93% Zn, including 1.50m at 0.89% Cu and 4.98% Zn. (refer ASX release 28 November 2018).

Ayoba represents the first new VMS discovery in the Areachap Belt in over 36 years and highlights the enormous upside over and above the large, high-quality Mineral Resource already defined at Prieska.

Geophysical surveys have also identified numerous compelling targets for both VMS style copper-zinc mineralisation and nickel-copper sulphide mineralisation within a 15km radius of Prieska.

VMS deposits generally occur in clusters in close proximity to one large or giant deposit, and often comprise two or three medium-sized deposits and five or six smaller deposits.

Despite Prieska being one of the single largest VMS exhalite bodies known in the world, the area around the deposit has had virtually no exploration in over 36 years. Now, with the application of advanced, modern geophysics and the latest geological thinking, Orion can vector into targets which offer outstanding opportunities for new VMS discoveries.