5 Jul 2012 07:00
5 July 2012
Sirius Minerals Plc
SM3A Assay Results and Drilling Update
§ Assay results of SM3A, the SM3 deflection, confirm similar thickness and grade of polyhalite as SM3 with 23.02m (true thickness) of 93.0% polyhalite in the Shelf Seam
§ SM4 and SM4A deflection completed with preliminary results confirming the presence of high grade polyhalite in the Shelf Seam approximately 4 miles from SM3
§ Coring at SM6 and drilling at SM7 commenced, 2D seismic survey under way
The Directors of Sirius Minerals Plc (AIM: SXX, OTCQX: SRUXY) ("Sirius" or the "Company"), the globally diversified Potash development group, are pleased to announce the mineralogical assay results of the deflection of the third borehole ("SM3A") and provide an update of drilling at the York Potash Project (the "Project").
Chris Fraser, Managing Director and CEO of Sirius said:
"The results of deflection drilling at SM3A and SM4A help to confirm the lateral consistency of the deposit which is an important step to achieve sufficient defined resource to underpin financing of the Project. These results provide further confidence of the world-class nature of the York Potash Project following the release of our maiden Resource delivering the world's largest and highest grade resource of polyhalite."
SM3 Deflection Assay Results
SM3A was drilled to investigate the lateral variability of the polyhalite deposit. Drilling commenced at 1,243m below Rotary Table ("bRT") to a total depth of 1,670m bRT. The maximum inclination of the deflection was 9.24 degrees and separation distance from SM3 was 57m at total depth. Coring of SM3A was between 1,477m and 1,598m bRT in the polyhalite-bearing strata of the Fordon Evaporite formation, 35m from SM3.
Independent mineralogical analysis of the drill core was carried out by the British Geological Survey ("BGS") at its Mineralogy, Petrology and Biostratigraphy Facility. Each sample was dried, crushed, milled and homogenised. A 4.5g portion of the milled sample was then micronised, and analysed by Quantitative X-Ray Diffraction. This is a non-destructive method developed by BGS to assess the mineralogical composition of rock and ore samples (with a typical accuracy of ±2.5% for mineral concentrations >60%; ±5% for concentrations between 60 and 30%; ±10% for concentrations between 30 and 10% and ±20% for concentrations between 10 and 3%).
The assay results of SM3A confirm the presence of thick and high grade polyhalite, consistent with SM3. SM3A entered the Fordon Evaporites at 1,425m bRT and as expected, the Upper Subcycle was chiefly anhydrite and halite. The Middle Subcycle was intersected at 1,495m bRT, where polyhalite was first encountered. As identified from visual examination of the core, polyhalite mineralisation extended mainly from 1,495m - 1,547m bRT. The analysed section included 47.08m at 83% polyhalite within which there was a 23.39m section at 93%. Traces of polyhalite continued further down to 1,547m however at a steadily reducing rate.
From the results of SM3 and SM3A, the Shelf Seam can be subdivided into an upper section which is very high grade and is laterally consistent between the two boreholes, and a lower part of the seam which is somewhat more variable in grade, texture and gangue mineralogy. As summarised in the table below, the total thickness of >80% polyhalite material was significantly higher in SM3A than in SM3 due to enhanced grade in the lower part of the deposit.
Total Thickness of >80% polyhalite | Upper Section | |||
Borehole | Thickness (m) | Average Polyhalite Grade (%) | Thickness (m) | Average Polyhalite Grade (%) |
SM3 | 30.0m | 81.4% | 22.03m | 91.1% |
SM3A | 46.9m | 83.0% | 23.02m | 93.0% |
Notes: (a) Thicknesses have been corrected for 5 degree dip; (b) Grade is moisture-free
The above results were accounted for in the geological model by changes that are believed to have occurred in depositional environment from the bottom to top of the Shelf Seam. The lower part of the Shelf Seam appears to have formed in a relatively higher energy, shallower water environment whereas the upper part of the Shelf Seam formed in potentially deeper and calmer waters.
SM4 and SM4A Preliminary Results
Drilling of both the SM4 and the SM4 deflection ("SM4A") was completed in June with the assay of SM4 currently under way. Wireline results indicate that the upper part of the Shelf Seam is high grade (expected >90% polyhalite) and approximately 5.5m thick in both SM4 and SM4A. The lower part of the Shelf Seam is thick in both boreholes, ranging between 11m and 14m, but is lower grade. SM4A was not cored as wireline analysis is believed to provide sufficient confirmation of grade and mineralogy to test lateral consistency going forward.
It is currently estimated 2.5m of 80% polyhalite exists immediately below the high grade section in SM4A referred to above, forming a potentially mineable section of approximately 8m. These results demonstrate the continuity of high grade polyhalite. SM4 is over 4 miles south of SM3, in a previously unexplored area.
Interpretation and Geological Model
The latest results provide further confirmation of the geological model. Boreholes SM3 (and SM3A) and SM4 (and SM4A) lie in the transition zone of the target mineral area - i.e. between the true Shelf Seam facies and the true Basin Seam facies environments of evaporite deposition. They demonstrate the lateral continuity of high grade polyhalite over a further 4 miles within the Project area.
Detailed logging of the cores and examination of the wireline logs has enabled better definition of the internal structure of the Shelf Seam in the Transition Zone. The upper part of the Shelf Seam, which is also the highest grade (>90% polyhalite), appears to be laterally consistent between parent borehole and deflection at both SM3 and SM4. The Inferred Resource estimate, announced on 11 June 2012, was based only on this upper, high grade section of the Shelf Seam at SM3. A lower but more variable section also exists, which contains further significant quantities of potentially mineable polyhalite.
The overall Shelf Seam thickness at SM4 is lower than that found in previous boreholes, but still exceeds the thickness used in the original Exploration Target calculations. As previously announced, the reinterpretation of the legacy seismic data suggests SM4 was close to the eastern edge of the Shelf Seam.
Additional Project Definition Update
Hydrogeological testing at SM6 to confirm the general pressure and flow of water in the sandstone layers throughout the area has been completed. This work was non site-specific and will help the wider understanding in the area for shaft freezing considerations and design of the sub-level hoisting station. A shaft pilot borehole will be required when a mine shaft location is determined. SM6 is currently coring through the Fordon Evaporites, once drilling of the SM6 "mother" borehole is complete a third deflection will commence ("SM6A"). Rig 5 has moved to SM7 in the Northern area of the Project, approximately 1 mile east from SM2 and 2.3 miles west from SM1 and has commenced drilling in the past week.
28 miles of new 2-D seismic data is currently being shot. This will tie the first six boreholes together and facilitate improved interpretation of the historic seismic data. Processing and interpretation of this data will take place over the next two months.
For further information, please contact:
Sirius Minerals Plc | |||
Peter McLennan(General Manager - Commercial)
| Tel: +44 8455 240 247
| Email: info@siriusminerals.com | |
NOMAD/ Joint Broker | Joint Brokers | Joint Brokers | Media Enquiries |
Macquarie Capital (Europe) Limited | Liberum Capital Limited | Jefferies Hoare Govett | Pelham Bell Pottinger |
Steve Baldwin, Sam Small | Michael Rawlinson, Clayton Bush | Peter Bacchus, Thomas Rider | Charles Vivian, Lorna Spears |
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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. It is developing the flagship York Potash Project in North Yorkshire, United Kingdom (North Yorkshire) and holds properties in the United States (North Dakota), and Australia (Queensland and Western Australia).
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.
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.
Qualified Person
Graham Clarke, Operations Director for Sirius Minerals Plc, who has reviewed this update, has over 26 years' experience in the potash mining industry. He has a Degree in Mining Engineering from the University of Nottingham and is a fellow of the Institute of Materials, Minerals and Mining and extensive operational experience gained at Cleveland Potash Limited in the mining of the Boulby Potash seam and the exploration and development of the upper Fordon Polyhalite seam.