At the St Ninians open cast coal mine in Scotland, the performance of the UK's first Atlas Copco ROC F9 CR rig has exceeded the expectations of both contractor and site operator.

Scottish Coal is extracting 1.3Mt of coal at an average rate of around 6,500 tons per week for power generation. The coal is lying in about 20 seams, which vary in thickness from only 100 mm up to two metres and the company needs to move about 80,000 m3 per week of overlying material.

"We needed a versatile rig which could drill both the softer sandstone at the mine and the much harder dolorite," says Albion Drilling's Managing Director Eamond Murray. "After looking at different alternatives, we chose to replace the small rigs with the Atlas Copco ROC F9 CR."

Gordon Martin-Smith (left), Atlas Copco Area Sales Manager, with Albion Drilling's managing Director Eamond Murray.

This is the UK's first ROC F9 CR, equipped with the patented Coprod top hammer drilling system which combines the speed of a top hammer with the hole straightness of DTH drilling.

"The new rig has given us greater flexibility on this worksite where the geology is quite complex and there are thin interburdens," adds Scottish Coal's site manager John Sanders."

The ROC F9 is drilling 115 mm diameter holes, varying in depth from 7 m to 15 m, on a 5 m x 5 m pattern. It needs to achieve a minimum of 1,200 m/week to meet the requirement of 30,000 m3 of blasted material per week.

The rig has peaked at 2,400 drill metres/week, is averaging 1,500 drill metres - and still only working at about 75 per cent of its capacity, says Eamond Murray. "From my figures, I believe the F9 has cut fuel consumption by nearly 60 per cent over the previous rigs.

"I am also pleased with its drilling performance, which has exceeded my expectations. We've definitely got the right rig for the job."

There's money to be saved on fuel! As the price of diesel fuel continues to skyrocket in Europe, with little hope of a reduction in the foreseeable future, fuel costs are rapidly becoming a major factor in drilling economy. However, despite the high prices, experience shows there are considerable savings to be made - up to 0.5 litres per drillmetre - by selecting the right drilling rig. This means that with an annual production of 50,000 metres, the potential saving is some 25,000 litres of diesel fuel per year - or 125,000 litres over a five-year payoff period for the purchase of a new rig. Fuel prices also vary greatly for contractors in Europe. In Britain, at 17p per litre for example, a saving of 125,000 litres represents GBP 21,250. In Germany, on the other hand, DEM 1.4 per litre gives DEM 175,000 - almost three times as much. Such potential savings can make a welcome contribution when evaluating an investment in new equipment.