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RUC Cementation Mining Contractors is able to supply a range of Raise Boring equipment, with the expertise and experience to tackle any project, anywhere in the world.

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Raise Boring

Ingersoll Rand RBM7 Robbins 61R Robbins 71R Robbins 83R Robbins 85R Wirth HG330 Strata 850 Strata 950

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Conventional Pilot Drilling

Picture: Conventional Pilot Drilling A Tri-cone pilot bit is normally used varying from 9 inches (229mm) to 15 inches (381mm). The 15 inch (381mm) bit is normally used on long holes with a 12⅞ inch (327mm) integral drill steel string with 10⅛ inch DI 42 tool joints.

Conventional Up-reaming of Pilot Hole

Picture: Conventional Up-reaming On completion of pilot drilling and at such time that the pilot hole breaks through into the lower excavation, a reaming head is attached to the end of the drillstring. The size of the reaming heads range between 1.2 metres and 7.1 metres in diameter.

It is a safe, efficient and cost-effective method of making holes through different geological formations with the use of powerful machines, high strength drillstring and reliable reamer heads. The maximum loading capacity of the drillstring limits the diameter as well as the length of the shaft. The loading is dynamic and only approximately calculateable as tensile, torsional and bending stresses are overlapping.

Down Boring with a Pre-drilled Pilot Hole

Picture: Down Boring In this case an oversize pilot hole is drilled. The cutting head is installed at the top of the pilot hole and drilling takes place in the downward mode. Rock cuttings are flushed down the oversize pilot hole to the bottom of the hole where it is removed. The down boring method is not used often as the risk of blocking the pilot hole and creating mud rushes at the bottom of the hole is high.