Cobalt Blue Holdings Ltd (ASX:COB, OTC:CBBHF) is making positive progress with processing ore from the Broken Hill Cobalt Project (BHCP) into concentrate for use in its Demonstration Plant to provide bulk samples for potential commercial partners of high-value cobalt products.
With the underground extraction of 4,500 tonnes of ore from the BHCP west of Broken Hill in Far West New South Wales completed, the company has been carrying out test-work on the concentrator circuit.
Phase one of this work has seen 500 tonnes of ore concentrated in the circuit with a further 2,500-3,000 tonnes to be concentrated in the next four weeks.
Ore feed hopper to concentrator circuit.
A key outcome of this testing has been the gravity circuit upgrading cobalt in ore to around 4,300ppm in concentrate, which is equivalent to around a five-times improvement in grade.
The company’s CEO Joe Kaderavek said: “The five-times grade improvement from concentration is a key project enabler, with phase one of this large-scale work continuing to confirm expectations.”
In the following Q&A with Proactive, Cobalt Blue outlines the progress it is making and why this work is being carried out.
1. In your latest update, you discuss a 5-times uplift in the concentrate grade. Can you please remind us of the ROM grade and the steps to this achievement?
The BHCP project is planning to mine ore from three surface deposits. The host rock (silica and feldspars) contains approximately 20% sulphides (mainly pyrite), with cobalt in ore typically varying from 500 to more than 1200 ppm.
Over the past month, ore was milled from 4mm top size to a target of 1.5mm top size using a roller mill, simulating the use of a High Pressure Grinding Roll (HPGR) mill in the circuit.
The pyrite grain is very coarse, which allows us to crush (rather than fine grind) the ore down to ~1mm ideal size.
Concentrate receival at the Broken Hill Demonstration plant.
Ultimately, we believe that regardless of whether the ore is low or high grade, the concentrate (being 90%+ pyrite) will report a consistent 5,000ppm or so cobalt grade.
2. Why are these steps important in this part of the process?
Upgrading the sulphide ore to a concentrate is an important step in developing an economically viable project. Roughly two-thirds of the cash costs occur beyond the concentrate step, in the refinery itself.
So, in simple terms, the refinery is only one-fifth the size of the mine (20% mass pull) and the refinery is where the majority of the operating costs are incurred. You can clearly see the benefit of upgrading the ore early in the processing.
Unfortunately, nickel laterite projects (with cobalt by-product credits) do not have the advantage of significantly upgrading the concentrate and are stuck at processing ROM-like grades through the refinery stage.
Commissioning of the kiln with concentrate.
3. What is different between the pilot plant from 2021 and demonstration plant this year, or in other words, why are you spending this significant amount of time and investment?
There are several reasons behind this:
- Proving up the economics defined in the pre-feasibility study (PFS). The demonstration plant will allow us to showcase the efficiency metrics: Are we consuming too much energy? Reagents? Are we extracting target levels of cobalt? We are confident this process works, but now it’s about proving up these efficiency metrics.
- The ability to provide prequalification samples to potential commercial partners.
- Investment in our people: we are training 25-30 shift operators in this unique process, all in preparation for the large-scale commercial plant - today’s operators will be tomorrow's shift managers.
- And lastly, the demonstration plant will become a metallurgical research centre – we’ll be able to task it with other projects like waste streams.
4. How is the timeline progressing?
The key milestones remain on track:
- The Demonstration Plant is up and running and will complete major operations by year-end.
- EIS field studies commenced earlier in the year and are progressing.
- The three contractors hired (Worley, GHD and SKR) to assist with the DFS are consistently on site – the final DFS will be complete by the third quarter of 2023.
- Commercial partner and offtake discussions are ongoing.
The expected development schedule for the Broken Hill Cobalt Project.
5. Can you elaborate on the offtake discussions?
Without being able to provide great detail, we can say that we are in the midst of significant discussions with a number of major EV makers and battery producers.
It certainly is an exciting time for Cobalt Blue!