Advanced explorer Blackstone Minerals (ASX: BSX) has confirmed its contractor is ready to commence a Ta Khoa refinery piloting program following delivery of key nickel and cobalt feedstocks to Perth laboratory ALS.
The program will treat a feed averaging 10% nickel, created from approximately 10 tonnes of sulphide concentrate and 10 tonnes of concentrate sourced from third party suppliers.
It aims to replicate the refinery’s full-scale flowsheet to confirm preliminary test work conditions and provide an insight into operating conditions of the continuous plant.
It will be broken up into extraction and refining phases of the flowsheet, with data expected to help Blackstone further develop engineering work for the plant’s design and close any gaps from previous testing.
The extraction phase will consist of four campaigns of between seven to 10 days and will cover the front end of the flowsheet entailing the feed concentrate handling (feed to pressure oxidation (POX) leach) up to the production of mixed hydroxide precipitate (MHP).
The campaign will aim to test the design envelope for the POX autoclave to maximise extraction of nickel, cobalt and manganese.
Refining will focus on the second half of the flowsheet including MHP releach and electrolyte purification (SX) through to NCM (nickel-cobalt-manganese) precursor precipitation and drying.
Testing will be over a combined 34 days.
In December, Blackstone was granted approval to recommence mining activities as part of its ongoing development of the Ta Khoa nickel project in Vietnam.
The company commenced approximately 1,000m of lateral development through the Ban Phuc disseminated orebody to generate nickel ore representative of the life of mine plant feed.
By the end of March, it had completed 541m to deliver over 2,000t of ore to the surface at an average rate of 136m per month.
Mining will provide quantities of ore for processing at the existing Ban Phuc nickel concentrator and subsequent pilot plants.
The concentrator was recommissioned in January after being placed on care and maintenance in 2016.
Blackstone said the efficiency of recommissioning activities and successful operation of the crushing circuit and concentrator gives the company confidence in its suitability for treating regional massive sulphide vein (MSV) ore bodies in an elevated nickel price environment.