£20 million Placing

THIS ANNOUNCEMENT IS NOT FOR DISTRIBUTION, DIRECTLY OR INDIRECTLY, IN OR INTO AUSTRALIA OR THE UNITED STATES (INCLUDING ITS TERRITORIES AND POSSESSIONS, ANY STATE OF THE UNITED STATES AND THE DISTRICT OF COLUMBIA). THIS ANNOUNCEMENT DOES NOT CONSTITUTE OR FORM A PART OF ANY OFFER OR SOLICITATION TO PURCHASE OR SUBSCRIBE FOR SECURITIES IN AUSTRALIA OR THE UNITED STATES. THE SECURITIES DISCUSSED HEREIN HAVE NOT BEEN AND WILL NOT BE REGISTERED UNDER THE UNITED STATES SECURITIES ACT OF 1933, AS AMENDED (THE "US SECURITIES ACT") AND MAY NOT BE OFFERED OR SOLD IN THE UNITED STATES ABSENT REGISTRATION OR AN EXEMPTION FROM REGISTRATION UNDER THE US SECURITIES ACT. NO PUBLIC OFFERING OF THE SECURITIES DISCUSSED HEREIN IS BEING MADE IN AUSTRALIA OR THE UNITED STATES AND THE INFORMATION CONTAINED HEREIN DOES NOT CONSTITUTE AN OFFERING OF SECURITIES FOR SALE IN AUSTRALIA OR THE UNITED STATES.

For immediate release: 10th March 2011

Sirius Minerals Plc

("Sirius" or the "Company")

£20 million Placing

The Directors of Sirius Minerals Plc (AIM: SXX, OTCQX: SRUXY), the globally diversified potash development group, are pleased to announce that the Company has completed a placing to raise gross proceeds of £20 million (the "Placing").

A total of 153,846,153 new ordinary shares (the "Placing Shares") have been placed at a price of £0.13 per share with certain institutional and other investors in the United Kingdom, the United States and Australia. Application has been made for Placing Shares to be admitted to trading on AIM and trading in such shares is expected to commence on or around 16 March 2011. The Placing Shares have been placed under the existing authorities granted by shareholders at the Company's last annual general meeting.

Chris Fraser, Managing Director and CEO of Sirius said: "The strong support Sirius received in the placing endorses our strategy to build the New Potash Powerhouse. These funds will enable Sirius to significantly progress our portfolio of potash projects, but in particular the York Potash Project. The critical studies and analysis we will now undertake will allow us to determine how best to develop the York Potash Project to create the most value for all stakeholders."

The majority of the proceeds of the Placing will be used to embark on a new drilling programme and a series of studies on the geological, environmental, and engineering aspects of the York Potash Project. The information gained from the drilling and seismic programme, plus the information already available to the Company from over 97,000 metres of historic drilling in the area, should allow the Company to define a JORC resource for the Project. In addition the Company is continuing to add to its mineral rights position in North Yorkshire.

Work will also commence on assessing process alternatives for polyhalite ore to produce saleable sulphate of potash ("SOP") and for the potential production of magnesium hydroxide as a valuable by-product. Detailed market studies will be conducted on the project's key markets in order to ascertain the depth and structure of the markets to enable Sirius to develop the appropriate market entry strategy to maximise value and minimise risk.

The Company is committed to developing the York Potash Project in such a way as to promote sustainable development and with consideration for all stakeholders. Environmental base line studies are planned to be initiated. These will form part of the Environmental Impact Assessment that will be submitted as part of the planning application process for the project.

Sirius will also continue to advance its Dakota Salts, Adavale and Canning Basin projects in parallel with the York Potash Project. Following the completion of the Company's first drill hole at Dakota Salts, the data gained from this hole plus other geological information, including seismic data, is being assessed by the Company and its consultants to determine how best to advance the project to the next stage. The Company is seeking to enter into a joint venture to explore and develop its Adavale Project, and in the Canning Basin it is continuing to analyse the data available in order to determine the best exploration and development strategy.

The expected application of the gross proceeds of the Placing is as follows:

The Placing Shares will be issued credited as fully paid and will rank pari passu with the Company's existing ordinary shares. The issue of the Placing Shares will represent approximately 14.9% of the expanded issued share capital. The Placing was carried out by XCAP Securities plc and EAS Advisors, LLC, an independent consultant to Merriman Capital, Inc.

A copy of the placing presentation is available on the Company's website.

As a result of the Placing, Capital Research Global Investors, a division of Capital Research and Management Company, will hold 75,739,645 Ordinary Shares representing 7.34% of the Company's enlarged issued share capital.

Following the issue of the Placing Shares, the total number of shares in issue and the total number of ordinary shares in the Company with voting rights will be 1,031,952,755. This figure may be used by shareholders in the Company as the denominator for the calculation by which they will determine if they are required to notify their interest in, or a change of interest in, the share capital of the Company under the Financial Service Authority's Disclosure and Transparency Rules.

For further information, please visit the Company's website www.siriusminerals.com. Alternatively please contact:

About Sirius Minerals Plc

Sirius Minerals is a globally diversified potash development company. Its primary focus is to bring on stream major potash mining facilities through the acquisition and development of projects overlying recognised potash deposits. Today it holds properties in the United Kingdom (North Yorkshire), the United States (North Dakota), and Australia (Queensland and Western Australia).

The Company is additionally progressing ongoing Research and Development initiatives into the secondary uses of salt and potash beds for energy storage and carbon dioxide sequestration.

Incorporated in 2003, Sirius Minerals' shares are traded on the London Stock Exchange's AIM market. Its shares are also traded in the United States on the OTCQX through the use of a sponsored ADR facility. Further information on the Company can be found at www.siriusminerals.com.