31 October 2011

Sirius Minerals Plc

(“Sirius” or the “Company”)

Wireline Logging Update

§  Wireline logging of SM1 successfully completed

§  Natural Gamma Ray Spectrometry confirms high polyhalite content in the two key massive polyhalite beds

The Directors of Sirius Minerals Plc (AIM: SXX, OTCQX: SRUXY), the globally diversified potash development group, are pleased to announce the completion of the wireline logging of its first borehole ("SM1") at the York Potash Project.

Following the completion of coring of SM1, announced on 27 October 2011, Schlumberger conducted a series of geophysical wireline logging tests on the hole.  These tests included natural gamma ray spectrometry, density, neutron and sonic logging to assist in mineral identification.  Spectral gamma ray tools resolve the natural gamma ray spectrum into its different components, including potassium; and so can be used to estimate approximate potassium contents in the borehole.

The Upper and Lower beds of massive polyhalite identified in the 27 October 2011 announcement, representing a combined 19 metres (true thickness) of massive polyhalite, gave average gamma readings across the whole of these intersections attributable to potassium that equates to polyhalite grades in excess of 80%.  Within these thick mineralised zones there were certain zones of significantly higher than average grades apparent.  These estimations of polyhalite grade align with the field assessment of the massive zones as having low levels of visibly identifiable halite and anhydrite inclusions.  

It is very important to note however that full chemical and mineralogical analysis is required to confirm the grades and continuity of the potash mineralisation in the recovered core. These are expected in approximately four weeks, as advised in the announcement on 27 October 2011.

Chris Fraser, Managing Director and CEO of Sirius Minerals said:

"Wireline logging is a valuable tool for potash exploration.  It provides a fairly reliable estimate of potash grades and has been used by Sirius in compiling its Exploration Targets for York Potash.

"Following on from the spectacular intersections announced last Thursday, these tests combined with the geologist's visual interpretation provide a very strong indication that the polyhalite grade encountered in the main massive polyhalite beds is in the upper end of the grade range presented in the York Potash JORC Exploration Targets."

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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 Innovation 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.

Competent Person’s Statement and Risk Statement

The information in this Stock Exchange Announcement that relates to Mineral Exploration results and

Exploration Targets, together with any related assessments and interpretations, have been verified by and

approved for release by Dr Frederick W. Smith FIMMM., CEng, CSci., a qualified geologist and full-time

employee of FWS Consultants Limited (“FWS”), Environmental and Geological Consultants. Dr Smith, who is a

Fellow of the Institute of Materials, Minerals and Mining (IMMM), has sufficient experience which is relevant

to the style of mineralisation and type of deposit under consideration and to the activity which he is

undertaking to qualify as a Competent Person for the purposes of the AIM Rules. Dr Smith and FWS consent to

the inclusion of the information contained in this announcement and the respective references to them in the

form and context in which they appear. The JORC Exploration Target estimates of quantity and grade are

conceptual in nature and there has been insufficient exploration to define a Mineral Resource on the property

and it is uncertain if further exploration will result in discovery of a Mineral Resource on the Property. The

estimates are not a Reserve or Resource statement in accordance with an AIM recognised Standard and should

not therefore be relied upon as such. It should be noted that the Pan European Code of Reporting or PERC

(that IMMM co-wrote) released in December 2008 and JORC are essentially identical on all key aspects relating

to compilation and quoting Exploration Targets.