North Dune contains an estimated 171 million tonnes of heavy minerals (HM) at an average grade of 1.5% or 2.6Mt using a 1% cut-off grade.
The grades contained a 38% slimes content, which makes the resource amenable to the hydraulic mining used elsewhere at Kwale, which is in Kenya.
North Dune would only require minimal capital expenditure due to the close proximity of the existing Kwale processing facilities, Base added.
Drilling on North Dune will continue in 2019 to increase the proportion of the resource in the Measured and Indicated categories.
Base said today it expects the existing reserves at Kwale to last until mid-2022, which rises to 2024 if it gets approval for an extension to the South Dune lease currently before the Kenyan government.
Broker Peel Hunt, however, believes the grades indicated at North Dune mean very little of it will be economic to mine though it adds there are higher grade pockets that could add up to four years worth of EBITDA positive production.
Shares were unchanged at 15p.