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Tue April 20 2021

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Dando develops drilling rig for slopes

25 Jun 15 Geotechnical specialist Dando Drilling International has produced a new specialist bit of kit for drilling on slopes.

The Dando Ibex can drill inclines of up to 55 degrees while maintaining a horizontal deck and vertical mast
The Dando Ibex can drill inclines of up to 55 degrees while maintaining a horizontal deck and vertical mast

The Dando Ibex slope drilling rig is track mounted and capable of dynamic sampling, SPT and rotary drilling on inclines of up to 55 degrees.

Product designer Rupert Coler said: “Last year Dando’s Dual Mast Terrier broke new ground by offering rotary and percussive drilling methods from two masts mounted side by side on the same small rig. We quickly realised that there was a market requirement for a rig like this but with the additional capability of drilling safely on steep slopes.”

Development of the rig was prompted by a commissioned from Bridgeway Consulting for a drilling rig to work on railway embankments. Bridgeway had recently bought a Dando D1500LHR, a small track mounted cable percussion rig that can crawl between railway tracks, so reckoned Dando could come up with something.

Rather than continuing to subcontract geotechnical investigation on embankments to other companies, Bridgeway decided to buy a rig that offered them all the features they recognised as important from their experience working in the sector.

“The finished rig has exceeded expectations,” said Dando sales engineer Jon Boltwood. “We’ve recently completed thorough testing and training at two locations in which the rig safely took samples and ran SPT on slopes over 55 degrees. Everyone involved was very, very impressed.”

Using the Sauer Danfoss Plus+1 automated levelling system, the Dando Ibex provides a vertical mast and horizontal deck and walkway on very steep terrain. A longitudinal slewing mechanism allows for uneven ground between the tracks, compensating for roll up to 15 degrees.

Rupert Coler explains the approach to climbing an embankment: “First you anchor cables from the onboard winch to a point high up the slope using so-called ‘duck bill’ ground anchors.  These provide stability when ascending and tether the rig safely while drilling.

“The operator then tracks the rig forward while simultaneously pulling in the cable on the winch using a specially designed radio remote control unit. When you reach the desired location, the deck can be progressed toward the embankment on a scissor mechanism so that there is effectively no gap between the deck and the bank.”

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While the radio remote control is a necessary safety feature given the hazards of traversing inclines with heavy machinery, the rig also has a swing-out control console with manually operated drill controls and a digital blow counter for use when drilling.

Once the rig is in position, a walkway comes out hydraulically to provide a level work area for the drill team, and easy access to the workbench, sample storage boxes and drill mast.

Jon Boltwood said that one of the design criteria was that the rig should be as compact as possible for easy transportation and access to tight work areas. To this end, Dando designed the track unit to expand on hydraulic rams from 1.5 metres wide to 2.1 metres, providing a stable base when climbing slopes and drilling, but a much smaller footprint when needed. The walkways also fold up.

At the drilling end, Dando’s Dual Mast system provides dynamic sampling, SPT and rotary drilling. A variable height mast extension allows 4 metre sections of rod to be tripped out on the winch.

Powered by a 27Kw Hatz silent pack diesel engine, the two-speed hydraulic top-drive rotary head can produce 362rpm for open hole drilling or coring, or alternatively be switched to 50rpm at 4189Nm of torque should the job require larger diameter drilling, with hollow stem augers for example.

Jon Boltwood sees an increasing market need for such a rig in the near future: “Railway projects such as the coming HS2 and HS3 developments are exactly what we had in mind when designing the Ibex.”

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