The suspensions come after an internal investigation uncovered a systematic misrepresentation of production volumes and sales for a number of years by a number of senior managers at the slate subsidiary of the company.
 
The company said the managers involved sought to conceal the financial implications of their actions through the pre selling of slate at substantially discounted prices.
 
As a result there are expected financial implications.  These involve a restatement of the 2005 net assets of the business by approximately £11m and a reduction in the expected pre tax profit of the slate business in the year to 31 December 2006 by approximately £13m.
 
The business is also expected to make an increased pre tax loss in the year ending 31 December 2007.
 
The ongoing investigation is currently at the preliminary stage, and as a result the board will delay the publication of its preliminary results. The publication is expected to be no later than 30 April.