Sovereign Metals has commenced a hydraulic mining trial at the Kasiya Rutile-Graphite Project (Kasiya) in Malawi, East Africa, as part of an optimisation study.  

Following a dry-mining trial in July, a temporary water storage pond has been filled with six million litres of ground water, predominantly from eight water boreholes on site, which will be used during the hydraulic mining trial. 

Concentrated slurry will then be used for the next set of tests in the in-pit deposition phase. 

As part of the ongoing Pilot Mining and Land Rehabilitation Programme (pilot phase), data from the dry-mining trial confirmed that no drilling, blasting, crushing, grinding or milling is needed before stockpiling material for processing into rutile and graphite products. 

Land rehabilitation will be a key part of the ongoing optimisation study, as Sovereign’s objective is to restore land post-mining to conditions that match or surpass existing agricultural yields.  

The pilot phase aims to showcase to local communities the successful rehabilitation of land for agriculture post-mining. These efforts are also expected to help Sovereign refine excavation and backfill techniques. 

Blending test work will commence after the completion of the hydraulic mining tests. This phase will involve backfilling the seven individual test pits using various ratios of fines and sand, to be followed by soil remediation and rehabilitation tests. 

Sovereign Metals managing director and CEO Frank Eagar commented: “With valuable insights gained from the dry-mining approach at Kasiya, we are now entering the next phase, which we expect to take three months to complete. Results from the pilot phase, in particular the analysis of dry-mining versus hydraulic mining, will be fundamental for the ongoing optimisation study.” 

Kasiya has a mineral resource estimate of 1.8 billion tonnes and holds the world’s second-largest flake graphite deposit.  

Advancements at Kasiya are supported by Rio Tinto, which has established a technical committee with Sovereign to oversee the pilot phase.  

Since raising its stake in Sovereign in July to 19.7%, Rio Tinto has announced its intention to make an additional investment of A$0.7m ($0.5m) and increase its stake to 19.9%, subject to the issue of additional shares.