Fergusson Group, the family-owned Scottish coal importing and distribution group, has seen profits more than halved from £10.2 million to £4.5m on a turnover unchanged at £119m.

The firm blamed "supply chain issues" and "rising operational and procurement costs" for the fall.

Tom and Alan Fergusson, joint owner-managers of the Falkirk-based firm, called the results "in line with projected expectations", representing "strong trading performance" for the group.

Fergusson, which operates throughout the UK and mainland Europe, supplies coal-based products to the domestic market and a cross-section of specialist industrial markets, including the energy sector. The firm moves around two million tonnes of coal per year, mainly from its hub at Hunterston Terminal, Ayrshire.

A spokesman declined to be drawn on the nature of the supply chain problems, apart from saying they "are now resolved".

He added: "The rise in operational costs can be attributed to increased fuel costs across Fergusson Group's retail distribution network, as well as increased operational costs at Hunterston following the extreme weather conditions of November and December 2010, and January 2011."

"Margins have been affected by a rise in operational and procurement costs, and we have faced increased pressure on market sales prices. However, we have been able to maintain sales by remaining focused on a retained customer base and specialist markets that benefit from our secure supply chain and sustained infrastructure investment.."

One UK coal industry leader, who asked not to be named, said the fall in profits in a relatively low-margin business was "not as dramatic as it might at first appear", as fuel price inflation and slight falls in the international coal price on a high-turnover business would soon translate into high percentage profit fall.

"Fergusson's is a very well-managed company but you don't need much change in revenue or costs to have quite an impact on the bottom line," he said.

Fergusson Group, which directly employs 200 people, has enjoyed a period of sustained expansion over the last two decades, growing turnover from £500,000 to £124m and acquiring more than 60 coal merchants across the country. The company also operates main depots in Inverness, Elgin, Tain, Fort William, Glenmoriston, Skye, Dundee, Mossend, Edinburgh, Dumfries, Kirkcowan and Uist.

The group has benefited recently from multi-million pound funding support from the RBS, which provided a flexible funding package that gave the company the working capital to build stocks in advance of the winter.

In December 2010, Fergusson posted pre-tax profits of £10.2m, the same as the previous year on turnover of £119m, down £5m from the previous 12 months.