Silage Corn Crop Study Results

4 February 2015

Sirius Minerals Plc

Silage Corn Crop Study Results

The Directors of Sirius Minerals Plc (AIM: SXX, OTCQX: SRUXY) ("Sirius" or the "Company") provide an update on the latest results from its ongoing global crop study programme.

This update provides results from the recently completed silage corn trials completed in conjunction with the University of Warwick. Corn harvested for silage is an important feed for animals, and the European Union grows ~5 million hectares of silage corn annually.

By utilising recognised trial protocols, polyhalite was tested as a source of potassium on silage corn against standard muriate of potash ("MOP") and sulphate of potash ("SOP"). This trial further demonstrated the improved macro-nutrient uptake that is offered by polyhalite, which has also been evident across the agronomic programme. Polyhalite achieved favourable results in various capacities including:

· Being supportive of nitrogen uptake which appears to be linked to polyhalite's readily available nutrient release rates. This showed a 52% increase in nitrogen use efficiency;

· Potassium is the most demanded nutrient by corn and polyhalite supports 44% greater uptake compared to MOP;

· Polyhalite seems to be the preferred source of macro-nutrients for silage corn, consistently improving nutrient uptake;

· Polyhalite delivered a 38% increase in dry matter yield over MOP;

· Tissue nutrient uptake measurements significantly increased over MOP (between 28% and 52%); and

· Polyhalite validated to increase crude protein content over MOP and SOP.

Chris Fraser, Managing Director and CEO of Sirius, commented:

"Our latest study offers further validation of the agronomic benefits of polyhalite. The improvement polyhalite can offer to nitrogen use efficiency is very significant in terms of its benefit to both crop yields and the wider environment.

"Following the success of our maiden animal feed sales agreement, it is also encouraging to see how the benefits of polyhalite's high nutrient value can be further shared across the food supply chain in such a major crop for animal feed."

An agronomy update presentation and webcast has been uploaded to the Company website www.siriusminerals.com.

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About Sirius Minerals Plc

Sirius Minerals is a potash development company with properties in the United Kingdom (North Yorkshire) and the United States (North Dakota). Its primary focus is the development of the York Potash Project which has the world's largest and highest grade deposit of polyhalite, a multi-nutrient form of potash containing potassium, sulphur, magnesium and calcium. 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.