Anson Resources (ASX:ASN) said it has completed a pre-feasibility study (PFS) for its Green River lithium project in Utah, through its unit Blackstone Minerals, according to a Tuesday Australian bourse filing.

The company said the study delivered first-quartile cost positioning with a C1 operating cost estimate of $3,837 per tonne of lithium carbonate equivalent (LCE), with brine reservoir pressure of 4,500 to 5,500 pounds per square inch, providing multiple cost advantages by reducing operating costs.

Permitting and approvals are largely complete, with a definitive feasibility study commenced and the project advancing toward a final investment decision, it added.

The company's shares fell 6% in recent Tuesday trade.