As detailed in the previous section the Company airfreighted approximately 1100kg of tungsten mineralised silexite material to Appropriate Processing Technologies (APT) in Zimbabwe. APT in conjunction with their associates Peacocke and Simpson (Johannesburg) commenced initial metallurgical testwork on approximately 200kg of material in early January 2016. Executive Chairman Dr. Pretorius travelled to Zimbabwe in order to supervise the various stages of the testwork. He also supervised bench-scale magnetic separation testwork on the APT gravity concentrate product undertaken by Scientific Services in Cape Town.
The Company commissioned TOMRA Sorting Solutions - Mining (TOMRA) to undertake ore sorting testwork at their test facility in Sydney on hand selected Torrington tungsten mineralised and unmineralised silexite utilising their X-Ray Transmission (XRT) system.
Results from the comminution testwork on the balance of the bulk sample and the magnetic separation and X-ray sorting testwork were all successful in providing potential processing options for the Torrington silexite ore. On this basis the Company requested Peacocke and Simpson to produce a conceptual plant flowsheet incorporating both X-ray sorting and magnetic separation into their wet gravity circuit.
Their conceptual flowsheet is shown below. Looking at the flowsheet the circled number 1 and 2 offtake points are the source of by-products with potential value referenced in the ASX announcement of 13 September 2016. Topaz concentrate would be collected from the Cleaner Spirals and a tungsten (wolframite) concentrate from the wet magnetic separator. Further details of the mineral processing and off-take products together with the conceptual plant flowsheet are given in the AGM presentation (ASX announcement 11 November 2016).
The next phase of the metallurgical testwork programme will comprise ‘proof of concept’ work and will be undertaken in the second half of 2017 utilising drill core collected during the February – April 2017 resource drilling programme.