Sirius Minerals : Tomato Crop Study Results

11 August 2014

Sirius Minerals Plc

Tomato Crop Study Results

§ POLY4 in both a blend and as a straight fertilizer outperformed MOP for tomato growth, yield and quality

§  POLY4 outperforms SOP by 11% in yield increases through higher fruit numbers and a 24% increase in fruit dry weight

§ POLY4 improved tomato quality through the increase in dry matter to pulp ratio and increased sugar content

§ Webcast available on company website

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

This update provides crop study results from the University of Florida which demonstrated the suitability and effectiveness of the York Potash polyhalite product, POLY4, as a crop input for tomatoes.  The annual world tomato market is large, comprising almost US$60 billion and representing 8% of overall world food production by value.  The majority of the industry is supplied by only five countries, which are the United States, China, India, Egypt and Turkey.

By testing polyhalite against traditional MOP and the premium SOP as potassium straights and against MOP as the main potassium source in an NPK blend, the recognised benefit by using POLY4 becomes clear through the following highlights:

§ POLY4 based NPK blend delivered a significant 74% yield increase over a traditional MOP based blend;

§ 57% increase in potassium uptake as a straight is indicative of greater nutrient use efficiency;

§ Despite high Mg soil levels a 158% increase in MgO nutrient content from using a POLY4 blend and a 211% increase in MgO nutrient content by using POLY4 over MOP as a straight fertilizer; and

§ An increase in pulp / juice ratio when utilising POLY4 in a blend or as a straight fertilizer - this increased ratio assists with longer shelf life due to better resistance to physical damage.

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

"This outstanding set of results is yet another demonstration of both the value of polyhalite and the large high value market potential that exists for this unique, multi-nutrient form of potash.  These results show the value of balanced fertilization and the validity of polyhalite as a bulk source of potassium, sulphur, magnesium and calcium in a form that is certified for organic use."

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

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 recognized 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 atwww.siriusminerals.com.