Ironbark Zinc (ASX: IBG) has delivered positive open pit optimisation studies for its Citronen Base Metal Project in Greenland which show a more than 15% increase in mill feed tonnage and a longer mine life.
The open pit ore scheduling study results show over 9 million tonnes of mineralised material optimised by open pit mining with very low strip ratios.
Importantly, this material has the capacity to supplement the underground mined mineralisation to the process plant and increase the mine life by an additional three years from the underground only sourced material.
The company was able to achieve the upgrade as a result of a previously announced increase in the Measured and Indicated base metal Resource at Citronen.
In early January, Ironbark announced an increase in both the grade and confidence of the resource at the project.
The company reported a 53% increase in resources in the higher confidence Measured and Indicated categories, an 11% increase in the total contained metal inventory and a 10% increase in the zinc and lead grade.
The global resource at Citronen now stands at 13.1 billion pounds of zinc and lead, using a 2% zinc cut-off, compared to the previously reported estimate of 132.6 million tonnes at 4% zinc and lead for 11 billion pounds.
Further upside to Citronen is that ongoing engineering work has indicated the potential to treat ore at a peak rate equivalent to 3.6 million tonnes per annum throughput by upgrading the primary and secondary crushers, with an overall relatively small additional capital cost.
Ironbark is currently investigating the maximum continuous production rate that could be obtained through these plant modifications.
An increase in processing rate would have an impact on the projects peak revenue generation, profitability, mine life, fleet and development requirements.
Mining studies have shown that mining at a peak rate of 3.6 million tonnes per annum is feasible from the Citronen Resource.
Citronen Feasibility Study
Ironbark is making solid progress towards finalising the Feasibility Study for the Citronen project. Early figures released in October last year indicate capital expenditure and operating expenditure could be lower than other major global mines.
The open pit optimisation provides the final mine scheduling data required for the Feasibility Study.
The next step for Ironbark is to complete the Feasibility Study and begin construction, which Downes anticipates will be towards the end of the year subject to the outcome of the Feasibility Study results.