Raise Boring Drill Pipe

A raise boring string works under a different set of loads from a surface rig: the machine sits on one level and the reamer is pulled back up through the pilot hole, so the pipe carries very high torque and tension in a hole it cannot be pulled out of easily. KISN raise boring drill pipe is made from 176 mm to 327 mm for exactly those conditions.

Material

Pipe is selected to U.S. standards 4145H and 4330V. Both are through-hardening alloy steels used for heavy downhole tools, chosen here for the combination of strength and resistance to cracking that a raise boring string needs. Material is listed for every size on this page.

Forged Uniform Structure

The pipe is forged to give a uniform structure and a refined grain, which is what makes the fatigue performance consistent along the length of the bar rather than only at the surface.

Threads

Threads are machined under imported thread gauges, so machining accuracy is controlled against a reference rather than by eye. The thread surface is treated to improve wear resistance and reduce the risk of galling — galling on a 10½ DI22 connection is expensive, and it is usually caused by thread surface condition rather than by overload.

Co-Development

For new machine designs or unusual hole diameters, KISN will co-develop the string with the customer. Tell us the machine, the hole diameter and the rock, and we will work to it.

Where It Works

Raise boring for ventilation shafts, ore passes and penstocks in underground mines and in civil tunnelling.

Where It Ships

Supplied to mining and tunnelling contractors in Africa, Southeast Asia and the Middle East.