WA update - Boyd PetroSearch appointment

For immediate release: 0700hrs, 1 October 2010

Sirius Minerals Plc

("Sirius" or the "Company")

Western Australia update - Boyd PetroSearch appointment

The Directors of Sirius Minerals Plc (AIM: SXX, OTC: SRUXY), the potash mining group, are pleased to announce Boyd PetroSearch ("Boyd") has been instructed to conduct a full review of existing and newly acquired 2D seismic data for its Derby Salts tenements in Western Australia. Sirius's Derby properties cover some 1250 km2 of claims in the Kimberley region of Western Australia that overlie the Canning Basin.

Under the review, Boyd will cross analyse new publically available 2D seismic data Sirius has acquired on the Canning Basin formation with the existing seismic and original exploration data the Company holds on the properties that was conducted by Rio Tinto during 2008-2009. Through this exercise the salt based resources of the Company's five Derby tenements will be more accurately delineated.

It is expected the seismic study and interpretation process will take a three month period to complete.

Chris Catlow, Chairman of Sirius, commented:

"The previous Rio Tinto work identified that the Canning Basin contains a vast evaporative salt based resource and we're excited to be continuing this work with Boyd in order to better understand at the earliest opportunity the potential scale and geology of the deposits in our Western Australian tenements. Their work will also allow us to identify initial test drill locations - assuming no fatal flaws are identified at this stage."

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For further information, please contact:

Website: www.siriusminerals.com