Laboratory and Ion Exchange Pilot Plant Studies Supporting the Field Leach Trial at the Honeymoon Uranium Project

The Honeymoon Uranium Project is an acid in situ recovery (ISR) mine in South Australia. The project contains three deposits: Honeymoon, Jasons and Goulds Dam. The measured resource consists of a total of 29 000 tU (6.5 M lb) U₃O₈ at an average grade of 1720 ppm U₃O₈ (1460 ppm U), with total resources (measured + indicated + inferred) of 28 800 tU (63.3 M lb) U₃O₈ at 660 ppm U₃O₈. The mine was previously operated by Uranium One for approximately 18 months, producing ~335 t of U₃O₈, before being placed on care and maintenance in 2014 as a result of the persistently low uranium price and production issues. Boss Resources acquired the project in December 2015. As part of the plan for restarting the mine, Boss performed a successful field leach trial (FLT) on an area of the deposit between August and December 2017. In support of the FLT, ANSTO Minerals undertook a comprehensive laboratory testwork programme. This included a study to optimize the leaching conditions, as well as column leaching of samples taken from the FLT area. The laboratory studies also identified an ion exchange (IX) resin capable of achieving significantly higher uranium loading than conventional resins under the elevated chloride concentrations in the Honeymoon leach liquor. As a result, ANSTO Minerals constructed and commissioned an IX pilot plant that operated over a 10-week period during the FLT. The success of this pilot plant means that IX could potentially be used as an alternative to the existing solvent extraction facility. This paper presents the results from the laboratory programme, as well as highlighting the success of the FLT campaign and associated IX pilot plant operation.