Raise Boring & Blind Drilling
In 1976, Frontier-Kemper had the foresight to recognize that some coal-mining methods that were new at the time, such as longwall mining, would have a great impact on the need for ventilation shafts. That’s when FKCI began working with the Ingersoll-Rand Company to jointly develop equipment that would be suitable for raise boring to the large diameters (15-to-18 feet) and depths (1,000 feet) necessary to construct these shafts. Up to that point, use of the raise boring method had been limited to the 10-foot-diameter range and applied mainly in hardrock metal mines.
Enter the RBM 211, with over 200,000-foot-pounds of torque. The system was developed complete with foundation frame, working platforms, rod storage, and a means for installing concrete lining. That system was later adapted for the slightly smaller RBM 7 SP and the giant Robbins 81R – which, in 1988, was used to bore a raise 2,145 feet deep with a diameter of 20 feet, 3 inches.
In recent years, FKCI has expanded its expertise to bore raises in highly populated urban areas. These drills are run by highly experienced teams, with many of the members having more than 20 years of raise boring experience. As a result, FKCI, which has bored more than 22 miles of raises in traditional mining-type environments, recently completed nearly 5,000 feet of raised shafts in New York City.
To provide solutions for mechanically excavated deep and large-diameter blind drilled shafts, Frontier-Kemper, Wirth GmbH, and ACI entered a joint cooperation agreement to build a blind shaft drilling system. The result is the FK350MT, one of the largest, safest, and most efficient A-Frame type drilling rigs in North America.
The FK350MT is equipped with many automatic features to enhance productivity and safety. These features, combined with the versatility of the A-Frame type mast, create a “one of a kind” rig never used before in the United States. As currently configured, the FK350MT has a working capacity of 350 metric tons, capable of drilling shafts up to 20 feet in diameter to depths of more than 1,000 feet.
The FK350MT's specialty drilling equipment – such as the rotary table, elevators, traveling block, swivel, kelly, drill pipe and all the bottom hole tools – are Wirth GmbH components specifically designed for large-diameter shaft drilling. FKCI designed and built all the other components, including the hoist, mast, substructure, hydraulic drive, and control station.
Frontier-Kemper employs some of the most experienced professionals in the shaft-drilling industry. The majority of our drilling crew is cross-trained in both raise boring and blind drilling, which means one efficient crew can construct multiple shafts utilizing either technique.
Frontier-Kemper has always been committed to providing cost-effective, technologically advanced solutions to owners in the mining and heavy civil industries. The addition of blind shaft drilling to our growing list of capabilities provides even more options to owners when their schedule or geological conditions warrant an alternative to conventional shaft sinking or raise boring.