Marine mining pioneer Nautilus Minerals this week reported an upgraded and improved mineral resource at its Clarion-Clipperton Fracture Zone (CCZ) project, in the Central Pacific, which it holds through its 100%-owned subsidiary, Tonga Offshore Mining.

Toronto-based Nautilus advised last week that the CCZ project’s compliant inferred mineral resource base increased from 410-million tonnes to 685-million tonnes (wet), while about 68-million tonnes was upgraded in the indicated category and 2.6-million tonnes in the measured category.

The new resource estimate included portions in the inferred, indicated and measured categories and the selected base-case scenario considering a nonselective bulk mining operation was calculated at an abundance cutoff of 6 wet kg/m2. Nautilus explained that, owing to the nodules effectively forming a single layer on the seafloor, ‘abundance’ (kilograms per square meter) was used to define the mineral resource tonnage.

According to Nautilus, polymetallic nodules occurred in water depths generally between 4 000 m and 6 000 m. They contained significant grades of manganese, nickel, copper and cobalt, and were formed by the precipitation of metals on the seafloor, either directly from ocean waters or through decomposing microorganisms and/or their effluent in benthic sediments.

CEO Mike Johnston noted that the updated mineral resource once more highlighted the significant potential of seafloor resources.

“Technological advances in mining, oil and gas and maritime technologies over the last 20 years now mean there are reasonable prospects for economic extraction of these massive mineralised systems. At Nautilus, we are both excited and privileged to be leading the development of this significant, currently untapped potential, first with our high-grade Solwara 1 seafloor massive sulphide (SMS) project and other SMS systems in the south-west Pacific, and now with this updated polymetallic nodule mineral resource in the CCZ,” stated Johnston.

Meanwhile, Nautilus announced last month that chairperson Geoffrey Loudon would retire and not stand for re-election at the upcoming annual general meeting (AGM) scheduled on June 1. Director Russell Debney had been appointed interim chairperson.

The board advised that it would embark on a thorough recruitment process to appoint a new independent director to the board following the AGM.