Base Resources Ltd (AIM:BSE) said the results of a pre-feasilibility study (PFS) of the Bumamani deposit support the extension of the life of its Kwale mineral sands mine in Kenya to mid-2024.
The PFS has concluded that it is economically feasible to mine smaller, higher-grade subsets of the Bumamani deposit and the Kwale North Dune deposit (referred to as P199) concurrently with the Kwale South Dune deposit, which would extend the mine life of Kwale by 7.5 months to July 2024, the AIM-listed company said.
The extension gives Base Resources time to develop further opportunities in Kenya, while maintaining operational continuity.
The company said a definitive feasibility study is now underway to improve the accuracy of project estimates.
The Bumamani PFS was undertaken after an earlier pre-feasibility study on mining significantly larger subsets of the North Dune and Bumamani deposits concluded this was not viable due to the low combined heavy mineral grade, high upfront capital costs, elevated slimes content and associated tailings disposal costs.
The North Dune mineral resources are estimated at 194 million tonnes (Mt) at an average heavy mineral (HM) grade of 1.5% for 2.9 Mt of contained HM, and the Bumamani mineral resources are estimated at 5.9 Mt at an average HM grade of 1.9% for 0.115 Mt of contained HM.
The subsets of these mineral resource estimates considered for the Bumamani PFS totalled 11.4 Mt of material at an average HM grade of 2.3% for 0.26Mt of contained HM. The 11.4 Mt of material is estimated to produce 34,000 tonnes of rutile, 113,000 tonnes of ilmenite and 13,000 tonnes of zircon.
Capital cost is estimated at US$13.6mln for the acquisition of land and the additional mine services and infrastructure that will be required, the company said.
Mining operations would use existing hydraulic mining units relocated from the South Dune and the mined material would be processed through Kwale Operations’ existing concentrator and mineral separation plants.
To maximise mining rates and better manage tailings, it is envisaged that the Bumamani deposit and the P199 section would be mined concurrently with the South Dune deposit, commencing from early 2023, with all deposits then being depleted at the same time in July 2024, Base Resource said.
Operating cost per tonne mined is consistent with current Kwale performance, but operating costs per tonne produced will be higher as a consequence of the lower heavy mineral grade resulting in lower production, the company explained.
Subject to the above assumptions, the Bumamani PFS has forecast net post-tax cash flows totalling US$16.5mln.
The company said its wholly owned Kenyan subsidiary, Base Titanium Ltd, has received an Environmental Impact Assessment Licence from the National Environment Management Authority to extend mining activity into the Bumamani and P199 deposits once it has secured mining tenure over these areas.