Blackstone Minerals Limited informed investors that key nickel and cobalt feed stocks for the Ta Khoa Refinery Piloting Program have been delivered to the ALS Metallurgical Laboratory in Balcatta Western Australia, and the contractor is in final preparation to commence piloting in April. In December 2021, Blackstone was granted approval to recommence mining activities as part of ongoing development of the Ta Khoa Nickel Project. Approval was received to perform mining works that will involve completion of ~1,000m of lateral development.

To 29 March 2022, Blackstone had successfully completed 541m of development, delivering 2,088t of ore to the surface, and averaging 136m a month. The existing 450ktpa Ban Phuc nickel concentrator was recommissioned in January 2022. Recommissioning works were completed by the skilled Ban Phuc operating and maintenance team, many of whom were part of the original team who operated the plant back in 2013-16.

The plant was placed on care and maintenance in September 2016 and has been meticulously maintained. The efficiency of recommissioning activities, and successful operation of the crushing circuit (refer Figure 3) and concentrator, gives Blackstone great confidence in its suitability for treating regional massive sulfide vein (MSV) ore bodies. Blackstone has the optionality to turn on the Ban Phuc nickel concentrator and process MSV orebodies, particularly in an elevated nickel price environment.

The Main purpose of the piloting program is to replicate the full scale TKR flowsheet to confirm preliminary test work conditions and provide an insight into the operation conditions of the continuous plant. Evaluation of the pilot plant data will help to further develop engineering data required for the TKR design and close gaps from previous testwork. The pilot plant program is broken up into two phases of the downstream refinery flowsheet: the Extraction Phase, and Refining Phase.

The Extraction Phase will consist of four campaigns of between seven to ten days and will cover the front end of the downstream refinery flowsheet entailing the feed concentrate handling/feed to POX up to the production of MHP. The focus of this campaign will be to test the design envelope for the POX Autoclave to maximise extraction of nickel, cobalt, and manganese. The Refining Phase will focus on the second half of the flowsheet, including MHP Releach, electrolyte purification (SX), through to NCM Precursor precipitation and drying.

The refining solvent extraction stages will be tested over a combined 34 days.