Total ore reserves now stand at 5.7 million tonnes, which supports a 7-year LOM assuming open pit mining methods at the Grants deposit and underground mining methods at the BP33 and Carlton deposits.
The project's current additional mineral resource inventory provides the potential to sustain the Finniss Project closer to 10 years.
Managing director Stephen Biggins said: “Today’s announcement of a seven-year mine life backed by reserves, and closer toward 10 years when including the project’s potential resource inventory, now allows us to seriously leverage the strength of location and production capacity to fully embrace such infrastructure as grid connection to power.”
Underground and open pit options
Core’s development of the Finniss Lithium Project is initially based on the development of the ore reserves within the high-grade Grants deposit as standard open pit mining operations and the construction of a simple 1 million tonnes per annum dense media separation (DMS) process plant to produce up to 180,000 tonnes of high-quality lithium concentrate with robust operating margins.
The underground pre-feasibility study (PFS) determined the suitability at BP33 and Carlton for sublevel open stoping which would provide a lower cost and lower risk method than other underground mining methods - with the ore to be trucked to the Grants processing plant.
Grants open pit design.
Scoping study resources
A scoping study was conducted in parallel to the PFS and determined that the material immediately below the Grants open pit was 97% inferred and 3% indicated.
An additional 599,891 tonnes of inferred resources were accessed immediately below the PFS design for BP33 where the scoping study schedule comprises 79% measured and indicated and 21% inferred.
At Carlton, an additional 1,241,255 tonnes of inferred resources were accessed immediately below the PFS design.
The Carlton schedule comprises 57% measured and indicated and 43% inferred with considerable scope to upgrade the inferred resource category.
BP33 underground design.
The combined development and production ore in the preliminary BP33 mine design includes 2.25 million tonnes at 1.40% lithium oxide or A$172/tonne net sales return (NSR), with the maximum mining production rate limited to 1 million tonnes per annum.
The BP33 underground development requires initial capital (pre-production) of A$23.31 million (including 10% contingency) with the total capital requirement over the LOM (including pre-production) of A$45 million (including 10% contingency).
The BP33 unit cost summary is:
- Development unit cost of A$7,667/metre;
- Production unit cost of A$62.60/tonne; and
- Processing cost of A$24.21/t (including crushing and screening, as per the DFS).
The combined development and production ore in the preliminary Carlton mine design includes 1.65 million tonnes at 1.08% lithium oxide or A$132/t NSR, with the maximum mining production rate limited to 1 million tonnes per annum.
The Carlton underground requires initial capital (pre-production) of A$30.78 million (including 10% contingency) with the total capital requirement over the LOM including pre-production is A$52.24 million (including 10% contingency).
Carlton unit operating cost summary is:
- Development unit cost of A$7,360/metre;
- Production unit cost of A$62.83/tonnes; and
- Processing cost of A$24.21/tonnes (including crushing and screening).
Carlton underground design.
Low start-up feasible
On the back of this increase in reserves, the LOM of the Finniss Project has doubled and can be achieved without substantial increases to the start-up capital for the Finniss Project.
Biggins said: “The downstream lithium battery supply chain and project financiers have recognised the significance of the recent Finniss Project approvals and the now extended feasible production capacity.
“We are well engaged with a number of parties globally for the remaining offtake of Core’s high-quality lithium concentrate and expect to be engaging with project financiers in the second half of 2020 to reach financial investment decision (FID).
“In the context of the substantial increases in resource and reserves of the Finniss Project this month, coupled with additional demand for offtake, Core is also likely to consider expanding production and revenues from the project above the current concentrate production capacity of 175,000 tonnes per annum.”
The increased resources, reserves and extended mine plan will be used to update the feasibility study for the Finniss Project as the company moves toward a final investment decision later in 2020.