Issue and Allotment of Ordinary Shares

14 August 2013

Sirius Minerals Plc

Issue and Allotment of Ordinary Shares following Exercise of Conversion rights

The Directors of Sirius Minerals Plc (AIM: SXX, OTCQX: SRUXY) ("Sirius" or the "Company") hereby announce that the Company has received notice of exercise in respect of convertible securities previously issued on 13 August 2013 at a conversion price of 12.2p per share, the details of which were announced to the market on 12 August 2013 pursuant to which 8,606,559 ordinary shares (the "Relevant Shares") fall to be issued. Application has therefore been made for the Relevant Shares to be admitted to trading on AIM with admission expected to take place on 20 August 2013. The Relevant Shares will rank pari passu in all respects with all existing ordinary shares in the Company.

Following admission of the Relevant Shares, the Company's enlarged issued share capital will comprise 1,362,582,827 ordinary shares with voting rights. This figure of 1,362,582,827 ordinary shares may be used by shareholders in the Company as the denominator for the calculations by which they will determine if they are required to notify their interest in, or a change in their interest in, the share capital of the Company under the FCA's Disclosure and Transparency Rules.

For further information, 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) and the United States (North Dakota). 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 a sponsored ADR facility. Further information on the Company can be found at www.siriusminerals.com.