SOUTH KOREA'S new high-speed railway between the capital Seoul and the northern city of Chuncheon will allow commuters to cover 80km in less than 45 minutes.
Main contractor Kusan Construction is building one of six tunnels on the project with a combined length of 12.5km. The company is using a Tamrock Jumbo rig equipped with Sandvik rock tool button bits, one of the first applications for the recently launched tools.
The 2.5km long Shu Chon tunnel is 10km south of Chuncheon and forms part of Sector 6 of the project. The tunnel, 9.6m wide at the base and 7.8m high, is being constructed by drill and blast.
The rig is using 45mm bits with 5.5m long rods. Spacing between the drill holes varies from 800mm at the centre to 700mm at the top.
The Jumbo rig generally drills 140 holes in three hours before blasting takes place, a procedure which it carries out twice a day, seven days a week.
Kusan estimates that drilling will be complete 'in early 2002'with the high speed railway due to open in 2010.