Durrant was previously the company's chief operating officer but became CEO earlier this month, with founding and former managing director Jeremy Robinson becoming non-executive chairman.
With degrees in mining and mechanical engineering, Durrant has experience in rare earths, bulk commodities and fertilisers.
The company is now looking at a staged approach for the Cummins Range project to reflect its size and phosphate content.
Late last month, RareX updated the resource for the project to 397 million tonnes grading 0.33% total rare earth oxide and 4.2% phosphate for 1.3Mt of contained TREO, including 280,000t of contained neodymium-praseodymium, plus 16.7Mt of phosphate.
It cemented the project as Australia's second-largest rare earths resource.
A further resource update, focused on the Phos Dyke, is due this month.
The update will be followed by a scoping study into a staged development.
Stage one envisages a fast-tracked direct shipping ore phosphate operation.
The company has already signed a memorandum of understanding with Agrimin for the sharing of road and infrastructure at Wyndham port and has an MoU with OrdCo, Kununurra's primary fertiliser distributor.
Stage two would involve phosphate beneficiation, followed by rare earth beneficiation in stage three.
It comes after phosphate-optimised flotation tests demonstrated the ability to float a combined monazite-apatite mineral combination with high recoveries, simplifying the rare earth beneficiation process flowsheet design from last year's scoping study.
"This staged approach is expected to lower the risk associated with building the full rare earth value chain outright at the beginning, by delivering a simpler and lower-cost DSO phosphate operation using existing infrastructure, whilst maintaining development towards a large scale, strategic, rare earth and phosphate critical minerals project," RareX said.
RareX aims to announced revised project economics this financial year and a feasibility study on stage one by the end of 2023.
The company flagged the potential to be in DSO production by 2025.
A definitive feasibility study on the second and third stages will be complete in the first half of 2025.
The work will be overseen by newly appointed study manager Kay Hoffman, who was most recently manager of ground control and water at Mineral Resources.
Shares in RareX opened unchanged at A6.1c, which is roughly a two-month high. The company has a market capitalisation of $35.3 million.
