US-based metals miner Allied Nevada Gold has revealed the results of the prefeasibility study (PFS) carried out in May which found that the Hycroft mine's mill expansion would cost an additional $66m, taking the total cost of the project to $1.3bn.
The extra funds were mainly due to design improvements, additional conveyors and crushed ore storage, added site costs and expanded sizes of the thickener tanks.
However, the study also showed positive signs, with 52 million tonnes of ore being added to the life of mine throughput and a decrease in mining unit costs from lower mining equipment fleet requirements and improved haul profiles.
The results will allow the company to proceed with plans to increase production at Hycroft to nearly 500,000oz of gold a year and the milling capacity to 120,000t a year.
The PFS also estimated that Hycroft would sell 13.7 million more gold-equivalent ounces at 13.1 million ounces, while generating a total revenue of $17.04bn over the mine life, which is an improvement on the previous estimate of $16.33bn, reported Mining Weekly.
Allied Nevada Gold CEO and president Randy Buffington said: "This project is one of the only economic, permitted large projects in the gold space today and has the potential to become a significant, low-cost producer with a long reserve life and large open resource behind that."
The PFS was carried out by M3 Engineering and Technology in collaboration with Allied Nevada Gold.
As part of the study, M3 developed the process flow sheet, capital cost estimate, operating cost estimate and financial model, whereas Allied Nevada developed the heap leach metrics, taxes, mineral reserves and mine plan.