The North Yorkshire Polyhalite project is now expected to need US$1.09bn, down 33%, while the project total capital requirement is now expected to reduce by 18% to US$2.91bn.
The estimate of the project’s net present value increases to US$15.2bn as a result, and the anticipated internal rate of return is now 28%, the company added.
These revisions come as a result of a detailed early engagement and competitive tendering with specialist contractors.
Sirius also highlighted ‘positive progress’ with its financing plans, and said that a number of parties undertaking detailed due diligence.
"By working closely with specialist contractors for almost two years we have been able to further strengthen the delivery plan for the project,” said Chris Fraser, Sirius Minerals managing director.
“The reduced capital funding requirement will also be a significant benefit to the already attractive economics that underpin our world-class project.
"We look forward to continuing to work with our contractors and their local supply chains as we move into the delivery phase and maximise value for both our shareholders and the wider economy."
Having been caught up in the early Brexit sell-off, Sirius shares rallied later as brokers reworked their sums.
House broker Liberum upped its target price to 50p (from 40p) given the lower dilution now likely from funding requirements.
“In Stage 1 the company will now be looking to raise $1.1bn through structured capital and equity (down from $1.6bn) and Stage 2 financing has been reduced to $1.8bn (from $1.9bn).”
Shore Capital added that reduced capital expenditure had exceeded its expectation
“An investment in Sirius will become progressively derisked as the company advances towards production, but we believe that it already offers a more robust, lower-risk investment with the prospect of better returns than typical of its peers.”
Sirius shares rose 3% to 18.5p.