Boretech reviews drilling policy

Grout stabilisation work is being carried out on the M42 motorway's concrete section using two US-built E-Z210-24DD manually-controlled drilling rigs, bought to avoid operatives suffering from hand and arm vibration.

Drilling contractor Boretech Construction bought the E-Z drill rigs to handle a workload of 11,580 holes - measuring 35mm in diameter and 575mm deep - and said that the two machines are drilling up to 800 holes in a 12-hour shift.

Boretech contracts manager Jon Vowles said: "The output of the two rigs, even with set-up time, is much faster on this depth of concrete slab than conventional manual drilling techniques.

"The rigs are also easier to use, and there's no hand or arm vibration transferred to operators as the units are mounted inside a frame, which takes all the vibration."

With holes drilled through the 325mm pavement slab and 250mm underlying lean-mix sub-base, the slab can then be stabilised by vacuum injecting grout into the voids beneath.

Boretech Construction said the successful and productive use of the rigs on the M42 contract has prompted the drilling specialist to review its drilling policy. "We will never drill holes by hand again," said Vowles.