PERTH (miningweekly.com) – Beneficiation and process design studies for the Wiluna uranium project, in Western Australia, have flagged a "substantial" reduction in the size and cost of the planned operating facility, Toro Energy said on Monday.

A redesign of the process flow sheet reduced the capital cost of the proposed hydrometallurgical plant by more than 40%, from A$134-million to A$78-million, and lowered the processing operating costs to about A$16/t run-of-mine feed.

Major advances in the studies included a two-million-tonne-a-year beneficiation circuit, which delivered 75% mass reduction, with 84% uranium recovery, a filtration and washing step, which removed saline water and produced a drier leach feed, unique wash water recirculation to increase reagent use and reduce reagent losses, and the introduction of ion exchange, which removed the need for evaporation ponds.

Toro told shareholders that the studies had not considered capital or operating costs outside the battery limits of the processing plant. Accordingly, total project capital costs and operating costs forecasts and revenue and production forecasts had not yet been determined.

Further studies are planned for 2017, which will focus on expanding testwork to improve the confidence of the beneficiation, filtration and leaching process, and to address lithologies of the Centipede/Millipede and Lake Maitland deposits, which contain clay.

Toro said that the revised cost structure allowed the company the opportunity to consider the optimal scale of the project, in particular the mining rate and uranium concentrate production, as well as reviewing the procurement and construction strategies.

Based on mining at the four deposits, the Wiluna project is expected to have a mine life of 16 years, with average production of two-million pounds a year of uranium oxide, for the first ten years of operation.