Teaming with a globally known process-design specialist, Barr assisted a junior mining company in developing an industrial-minerals solution mine and processing facility. Ultimately, our team developed the entire process, plant, and site design and prepared the technical and economic reports needed to comply with the Australasian Joint Ore Reserves Committee (JORC) standards, which allowed our client to further develop this project through additional external investor support.
Initially, we conducted a scoping study to assess process options for producing 90,000 tonnes of boric acid per year, and used the information to develop several flowsheet options and provide our client with AACEI Class 5 cost estimates. We then recommended a go-forward option that subsequently served as the basis for a prefeasibility study on producing not only the 90,000 annual tonnes of boric acid but also a byproduct of saleable gypsum.
At the same time, Barr developed a pilot-testing campaign for the site and designed and set up an on-site analytical laboratory and led the pilot test, which was conducted around the clock by Barr and client staff over the course of several months. That was followed by a feasibility study.
Because the borate resource also contained notable levels of lithium, our client asked us to explore the potential for recovering that metal along with the boric acid. We determined, however, that the very-low-pH solution required to liberate the lithium would have negative technical and economic consequences. High volumes of acid would be required, and non-valuable minerals would be released from the deposit along with the lithium and need to be disposed of.
The final overall process-plant embodiment called for low-pH solution mining, solution clarification, solvent extraction, boric acid crystallization, gypsum precipitation with acid regeneration, a zero-liquid-discharge circuit, and Mannheim furnace production of sulfate of potash, with the hydrochloric acid byproduct then being used in the solution mine.
The project continues to progress via a staged-development approach to reaching the ultimate production goal of 90,000 tonnes of boric acid a year.