Sirius' shares fall 7% after delay announced

Shares in miner Sirius Minerals fell heavily today, despite the firm saying the quality of minerals found at its York Potash Plant had exceeded expectations.

The firm said final analysis of samples at the site confirmed the thickness and grade of polyhalite seams was "world-class and has exceeded...expectations".

"We are continuing to consider and analyse potential improvements to the mining and development concept," the company said.

"The thickness of high grade polyhalite within a much wider zone of banded material presents multiple mining and process opportunities."

But it also announced that drilling progress at its 'SM2' site had been slowed by a series of fluid loss zones which have been encountered as the hole approached commencement of coring depth.

The firm's shares fell 7% in morning trading following the announcement.

Completion of coring was now expected early in January 2012, it said.

The technical details the sample results were:

- 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)