Following previous Geo Studies, Sub-Level Longhole Stoping (SLOS”) has now been selected as the preferred mining option. SLOS offers the project higher productivity rates, whilst reducing overall costs.
Figure 1 Toral Mining Plan
Metallurgy and Process
Updates to the metallurgical approach and process design including ore sorting delivered several benefits to the project, including reducing capital costs for the same metal production, increasing metal production for the same capital cost, and reducing overall costs of production. This proven method of pre-concentration was considered key to increasing the value of material mined from such zones prior to subjecting it to conventional flotation. Based on sampling results, EUZ decided to adopt sorting as a pre-flotation stage for all material generated in the Toral mine plan in order to fully exploit the benefit of this technology. Grinding and flotation test work including grind calibrations, bond work index determination, and froth flotation was then undertaken on two fresh samples as well as on the products of the abovementioned sorting test work undertaken.
Figure 2 Toral Crushing, Sorting, Grinding and Flotation Flowchart
Key Financial Metrics
The study returned a $156m Net Present Value at an 8% discount rate and a 31.3% Internal Rate of Return (IRR) with a projected 49% operating margin. The NPV and IRR results indicate significant production expansion from the 2018 study, with enhanced economics derived from a change in the mining method, increased run-of-mine, the ore sorting addition, and increased understanding of the project’s metallurgical characteristics.
Figure 3 illustrates the total revenue of $962m over the life of the mine with Zinc being the major contributor of $526m
Figure 3 – Revenue Contribution Upfront Capex for the project is estimated at $79m with a $73m peak funding requirement. Figure 4 demonstrates Payback is calculated as occurring in year 4, however it must be noted that this is extended somewhat by the low mining rate and low grades in the early years, and belied by higher rates and grades in the intermediate years of the project.
Figure 4 – Projected Revenue and Costs Study Conclusions
The updated study concluded that Toral’s production profile demonstrates ‘a very robust project capable of producing high grade saleable concentrates within an EU jurisdiction.’
Bara has advised EUZ to move to the Pre-Feasibility Study stage.