Cobalt Blue Holdings Ltd (ASX:COB, OTC:CBBHF) continues with the development of a Demonstration Plant for the Broken Hill Cobalt Project in New South Wales with ore extraction underway and staged commissioning of the site concentrator to start shortly.
The company has completed decline development at the Pyrite Hill mine site west of Broken Hill, with the first 1,000 tonnes of ore delivered to surface for processing.
Commissioning of the concentrator at Pyrite Hill forms a key part of the initial production of bulk samples with mined ore to be crushed, milled and treated to produce a cobalt-pyrite concentrate at this site.
Cobalt concentrate will then be trucked to the Demonstration Plant in Broken Hill for extraction and recovery of cobalt as mixed Hydroxide Precipitate (MHP) and/or cobalt sulphate.
Large-scale kiln and sulphur recovery equipment to complete plant construction is at the ready in Broken Hill.
Validation of processing technology
Commenting on the progress, Cobalt Blue CEO Joe Kaderavek said: “Mining/crushing operations are now underway with progressive commissioning across the flowsheet to follow.
“We anticipate the demonstration plant will deliver more than 3,000 kilograms of cobalt products from June to November, providing technical validation of our processing technology, product quality and underpinning project investment.”
Kaderavek went on to say that the company expected significant commercial interest from potential end-users over the second half of the year.
Two-phase demonstration
The demonstration plant consists of two phases of operation.
First, mined ore will be crushed, milled and treated to produce a cobalt-pyrite concentrate at the Pyrite Hill site and during the second phase the concentrate will be trucked to the Demonstration Plant in Broken Hill for extraction and recovery of cobalt products.
Bulk sample extraction
The underground portal was established in late April and the decline subsequently advanced 85 metres in readiness for ore drive development and extraction of the targeted ore tonnage.
The decline intersected mineralisation from 68 metres with the advance delivering the first 1,000 tonnes of ore for processing.
Around 3,500 to 4,000 tonnes of ore will be mined from Pyrite Hill to support 20 weeks of continuous operation of the demonstration plant.
Roughly 78 metres of planned development remains including:
- 48 metres of cross strike development targeting intersection of the deposit footwall; and
- 30 metres of strike parallel development.
Construction of key equipment complete
Construction and installation of key equipment at the Pyrite Hill site has been completed with the finalisation of the electrical and process control system.
Pyrite Hill site concentrator including gravity spirals.
The multi-stage crushing plant has been mobilised to site and to date has processed and screened some 900 tonnes of ore to -20 mm.
Of this, approximately 40% passing -4 mm has been directly forwarded to the plant for final milling reducing the ore feed to a desired particle size of -1 mm. This material is then being fed into the gravity concentrate circuit at a nominal rate of 9–10 t/hr.
Crushing operations will continue on a campaign basis, with recirculation of oversized material and processing of remaining ore tonnes as mining progresses.
Pyrite Hill geology
The Pyrite Hill deposit extends over 1.2 kilometres along strike, over 300 metres down dip and varies in thickness from 10 to 100 metres.
Mineralisation is hosted by a quartz-albite gneiss and is characterised by the presence of disseminated pyrite concentrated parallel to primary foliation. The remaining development at Pyrite Hill is planned to extract material from around 40 to 50 metres below surface, where the orebody demonstrates an apparent thickness of 65 metres.
The development is 3 to 6 metres below the interpreted top of the fresh rock surface.
Ready for first batch of concentrate
In Broken Hill, installation is continuing in readiness for delivery of the first batch of concentrate from Pyrite Hill.
With receipt of the new large-scale kiln and sulphur recovery equipment, all major components are onsite to complete the plant construction. Current works are focused on finalisation of the process control system.
The pressure oxidation leach circuit at the Broken Hill Demonstration Plant.
Market strategy
The company plans to maximise payable cobalt while participating in the strong growth of the lithium-ion battery market.
In contrast to the traditional cobalt mining model, COB’s is an integrated refinery model capable of delivering an intermediate mixed hydroxide product (MHP), which subsequently can be further refined into battery-grade cobalt sulphate.
The BHCP process flowsheet and production target parameters.