Exercise of options

18 June 2018

Sirius Minerals Plc

Exercise of options

Sirius Minerals Plc ("Sirius" or the "Company") announces that the Company has received a notice of exercise in relation to share options exercise granted to an ex- employee in November 2012, pursuant to which 474,990 ordinary shares (the "Relevant Shares") fall to be issued. The share options are exercised at 29.2p per share raising a total of £138,697.08. The monies will be used for general working capital purposes.

An application has been made for the Relevant Shares to be admitted to the premium listing segment of the Official List of the Financial Conduct Authority (the "FCA") and to trading on the London Stock Exchange plc's main market for listed securities, and dealings are expected to commence at 8.00 am on 19 June 2018. The Relevant Shares will rank pari passu in all respects with all existing ordinary shares in the Company.

In accordance with the requirements of the FCA's Disclosure Guidance and Transparency Rules 5.6.1AR and 5.6.2G, the Company confirms that the enlarged share capital of the Company following Admission will be 4,690,010,787 Ordinary Shares in aggregate, each with equal voting rights. No shares are held in treasury. The above figure may be used by shareholders (and others with notification obligations) as the denominator for the calculations by which they will determine if they are required to notify their interest in, or a change to their interest in, Sirius Minerals Plc under the FCA's Disclosure Guidance and Transparency Rules.

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About Sirius Minerals Plc

Sirius Minerals Plc is focused on the development of the Woodsmith Mine, which will access the world's largest and highest grade polyhalite deposit located in North Yorkshire, United Kingdom. Polyhalite is a unique multi-nutrient fertilizer, which can be used to increase balanced fertilization around the world. Sirius Minerals' shares are traded on the Premium List of the London Stock Exchange. 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.