Bradway Tunnel Refurbishment

The scheme involved drilling vertically upwards using a Beretta T21 with rotary percussive action (DTH-90mm diameter). Radial holes were drilled around the outside of nine steam train smoke shafts, for the installation of drainage screen pipe to collect and deliver ground water accumulation within and around each shaft. The works were carried out on a 24/7 shift basis from rail based apparatus.

The innovative design of the Beretta T21 permits settings of the mast and control panel in the best possible position for the drilling of holes with any tilt angle. It is perfectly suited for drilling in locations where access is restricted. The mast is easily detached from the drill fame and, by extending the hydraulic hoses, it can be positioned independently and remotely from the base. The base is mounted on retractable rubber tracks and has four hydraulic jacks for raising / leveling / stabilising the unit.

The rotary drilling head has three motors (170/85/56) rpm to suit various drilling applictions which include: diamond drilling/coring, rotary drilling, down the hole, overburden drilling and auger drilling.



Operational details:

  • Mast working clearance 2.5m standard (a shorter mast can be fitted if necessary)
  • Drive Yoke – choice of either 23/8" reg box (female) or eta pin (40mm dia)
  • Stroke below drive – 1.525m (ie distance between drive yoke and top of clamps)
  • Hydraulic clamp – 160mm(max) 35mm(min )
  • Drive motor 1 – 0–56 rpm, max torque 172Kgm
  • Drive motor 2 – 0–85 rpm, max torque 114 Kgm
  • Drive motor 3 – 0–170 rpm, max torque 57Kgm
  • Retractable tracks – 1.030m out, 0.850m
  • Pull-push 1200 kg
  • Hydraulic Jacks – 4