Ironbark Zinc Ltd (ASX:IBG) is continuing development work on updating the processing, logistics, communications and project execution elements at the flagship Citronen Zinc-Lead Project in Greenland.
Following the end of the September quarter, Ironbark commissioned a report by Canadian ice shipping specialist Fednav Ice Services to inspect shipping conditions at the project.
This comes as the trend towards significantly improved shipping conditions seen across the Arctic region is mirrored at Citronen.
Bespoke shipping solution
Managing director Michael Jardine said: “As is well known, Citronen’s high Arctic location will necessitate a bespoke shipping solution and Ironbark is pleased to again be working with ice shipping specialists Fednav in updating its shipping plan.
“The trend towards more open waters during the Arctic summer is now widely cited and its impact on de-risking the shipping operation at Citronen is potentially significant.
“Whether it’s a potentially longer shipping season, younger ice on the shipping route, a larger charter fleet to choose from or the associated capex and opex savings, Ironbark is focused on maximising the benefits presented by this long-term opportunity.”
Highlights from the report include the fact that multiple options exist to manage shipping to and from the project, from ice-breaking bulk carriers to close-coupled towing regimes.
Ironbark is likely to focus on the chartered fleet for its shipping solution, given the relative surplus of polar class vessels that could be available for charter during the shipping window at Citronen Fjord when ice conditions are more favourable.
During September, the company completed phase-1 of a metallurgical review of the historic test-work and process flowsheet for Citronen.
The review was undertaken by Mineralis Consulting in Brisbane, one of the world’s pre-eminent consultants in the metallurgical processing of Sedimentary Exhalative (Sedex) zinc-lead ore bodies.
This work continues the current 2020 refresh of the Citronen feasibility study.
Key findings included:
- The Citronen ore body sits firmly within the well-understood family of Stratiform Sedex zinc-lead deposits for which processing risks are well-studied and understood. Such deposits constitute the majority of the world’s largest historic and currently operating zinc mines;
- Previous test-work was confirmed to be of high quality;
- Improvements to processing technology (especially flotation) since the original Citronen FS test-work was completed offer the opportunity to further optimise metallurgical performance; and
- Opportunities to streamline the process flow sheet were identified, in particular, the primary comminution and concentrate regrind circuits.
Mineralis has now been engaged to complete a phase-II study focused on the following:
- Refining the proposed flotation circuit with a focus on the drivers of metallurgical performance;
- Increase focus in circuit on zinc recovery;
- Undertake limited new confirmatory metallurgical test-work for any proposed circuit modifications. This will be done with existing core stored in Perth, Western Australia; and
- Update the process design to facilitate preliminary engineering.
The Phase-II work is underway with completion expected in the first quarter of 2021 and this will likely coincide with the ongoing work to update the historic Citronen feasibility study.
Updated mine plan
In July 2019 Ironbark engaged leading international mining consultancy Mining Plus to conduct an optimisation study designed to refresh the mine plan.
The optimisation study highlighted several areas where the existing mine plan could be improved, particularly given the long passage of time since the Citronen mine plan was first resolved.
Mining methods and techniques have evolved considerably in that time, and the Ironbark board commissioned a more in-depth review of the existing mine plan in early 2020.
This included a comprehensive revision of the feasibility study (FS) for Citronen to ensure that it reflected the significant advance in technologies and changes in pricing that have occurred since the original study was first completed.
As part of that 2020 program Ironbark engaged Mining Plus to undertake the mine plan optimisation using current technologies and costs, and, to report a maiden JORC ore reserve for the project.
The study was completed during the quarter and final results announced on September 7, with further supporting information provided on September 18.
Ironbark’s newly optimised Citronen mine plan considerably de-risks the mining operation in several key areas, as well as significantly improving both the project economics and overall understanding of how the ore body is optimally mined.
Maiden ore reserve
On September 14, the company announced the maiden JORC ore reserve for the underground deposit at Citronen of 21.3 million tonnes at 6.3% zinc equivalent containing 1.3 million tonnes of zinc and 100,000 tonnes of lead.
This was another major step in de-risking the Citronen investment proposition given the much greater confidence level implied in moving to an ore reserve.
It also distances Ironbark from its developer peers and satisfies a pre-condition very likely to be encountered by Ironbark when it moves into a more active project finance process in 2021.
With the recent EL6925 tenement renewal application having been received for the Fiery Creek Gold Project in New South Wales and the continued strong upwards movement in the AUD gold price over 2020, during the quarter Ironbark resolved to revisit the copper and gold potential at Fiery Creek with respect to a prospective new exploration program.
A 2020 review of Fiery Creek by Peter Leaman at Geological Services has confirmed that mineralisation remains underexplored at depth and exploration along the strike of the workings is incomplete.
Preparatory work started during the quarter:
- A consultant structural geologist has been engaged to review the existing data and make recommendations regarding drill targeting;
- Further assessment of the permitting process to enable drilling with SCA areas of EL6925; and
- Consideration of the funding pathway for any planned exploration, including IBG sole funding or a JV/ farm in structure with prospective gold partners.