Press release
2011-12-13 02:51:22-05
13 December 2011
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- Final assay results confirm first assay results released on 28 November
- 23.3 metres (true-thickness) of 95% polyhalite (27.5% K2SO4) aggregated across three beds
- Main high grade bed is 11.0 metres (true-thickness) of 97.1% polyhalite (28% K2SO4), including two high grade zones totalling 9.6 metres of 99.5% polyhalite
- Total polyhalite zone of 49.3 metres (true-thickness) of 66% polyhalite (19.1% K2SO4)
The Directors of Sirius Minerals Plc (AIM: SXX, OTCQX: SRUXY), the globally diversified potash development group, are pleased to announce the full chemical assay results of the first bore hole drilled at the York Potash Project.
Results from the first batch of chemical and mineralogical analysis of the three key target seams were summarised in the announcement dated 28 November 2011. That release contained the full summary of the two potassium chloride seams. Analysis of the second and final batch of polyhalite bearing samples has now been received and is summarised in this release.
Chris Fraser, Managing Director and CEO of Sirius said:
“The final batch of polyhalite samples has confirmed and extended the polyhalite results released on 28 November. The thickness and grade of the polyhalite seams is world-class and has exceeded our expectations. We are confident that the future holes will confirm the quality of this deposit.
“We are continuing to consider and analyse potential improvements to the mining and development concept. The thickness of high grade polyhalite within a much wider zone of banded material presents multiple mining and process opportunities. A significant amount of work is ongoing in our engineering and development studies, which will help us maximise the value of this large deposit.”
Polyhalite Assay Results
For the background and the analysis undertaken on the cores recovered from SM1 please refer to the announcement dated 28 November 2011.
The Fordon Evaporite Formation, within which lies the polyhalite zones, was intersected at 1,390.1m below surface (1,255.4m below sea-level), with the first signs of polyhalite inter-beds at 1,580.1m below surface (1,445.4m below sea-level). The proportion of polyhalite increased gradually until, at 1,613.4m below surface (1,477.7m below sea-level), the first bed of massive polyhalite rock (the “Upper Bed”) was encountered. This was dipping at approximately 35⁰ and so, although 9.75m was cored, the true seam thickness is approximately 8.0m. It was followed by 6.38m (5.2m true-thickness) of low-grade polyhalite and halite, then a second bed of massive polyhalite rock (the “Middle Bed”) was encountered. This was cored for 15.62m (11.00m true-thickness @ 45⁰ dip). Following a further 8.31m (6.8m true-thickness) of banded polyhalite, a further bed of massive polyhalite (the “Lower Bed”) was cored for 11.2m (10.4m true-thickness).
The three massive polyhalite beds were sampled at approximately 0.5m intervals – taking care to isolate and analyse separately a 0.55m (0.4m true-thickness) parting of anhydritic material indicated on wireline logs as lying within the Middle Bed. The results are summarised follows (quoted on a moisture free basis):
Upper Bed 8.0m true-thickness at 92.31% polyhalite. The upper part of the bed is the highest grade (97.5% polyhalite), tailing off gradually downwards. Halite is the gangue mineral.
Middle Bed 11.0m true-thickness at 97.06% polyhalite. This includes 9.6m true-thickness of 99.5% polyhalite separated by the anhydritic-rich band (0.4m true-thickness) that occurs approximately mid-seam. Other than this anhydritic band the gangue is halite.
Lower Bed This bed can be divided into three sections. The upper, most massive, Section A resembles the other massive polyhalite seams and is approximately
4.32m true thickness at 94.77% polyhalite. Section B is 2.2m true thickness at 78.17% polyhalite and Section C is 3.9m true thickness at 52.89% polyhalite.
The three highest grade seams (Upper, Middle, and Section A of the Lower Seam) represent an aggregate true thickness of 23.3m at 95% polyhalite. The entire zone (roof, seams, bands, etc…) cored was assayed from 1,604.01m to 1,669.0m from Rotary Table Elevation (“RTE”) (1,464.85m to 1,529.84m below sea-level).
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