Raise boring machine construction is a non-blasting rock shaft forming technology for vertical shafts. Raise boring machines, vertical shaft boring machines and vertical shaft drilling rigs are collectively known as the three major full-face shaft-forming equipment.
Raise boring machine construction technology is widely applied in various engineering sectors including transportation, water conservancy and hydropower, mining, and military industry. It is commonly used for vertical shaft excavation in civil engineering and mining projects, typically to drill through two parallel passages or connect underground roadways to the ground surface.
Application of Raise Boring Machines
Application area
Phased Temporary Works
Temporary Works
Permanent Works
Coal system
Various waste rock pass boreholes (coal bunkers, blind shafts, main shafts, auxiliary shafts, ventilation shafts)
Mining area air raises, coal passes, waste rock passes, gas drainage boreholes, safety rescue boreholes
Ventilation shafts, material hoist shafts
Hydroelectric system
Various pilot shafts (penstocks, outlet shafts, surge shafts, elevator shafts)
Ventilation raises during construction (long & large tunnels, underground surge chambers), reinforcement boreholes
Ventilation raises and monitoring boreholes for permanent underground structures
Other mines
Various pass raises (shafts, ore bunkers)
Mining area air raises, ore passes, muck passes, material & personnel raises
Ventilation boreholes, etc.
Underground constructions
Various pilot shafts
Ventilation boreholes during construction
Ventilation shafts, access shafts
How does Raise Boring Machine Work?
The working principle of a raise boring machine is as follows: an electric motor drives a hydraulic motor, which powers the water swivel. Hydraulic force transmits torque to the drill string assembly to rotate the drill rods and drill bits. Under drilling pressure, the roller cutters mounted on the pilot bit or reamer roll purely or slide slightly along the rock face at the bottom of the borehole. Meanwhile, the axial tensile and compressive forces generated by the main machine’s cylinders act on the pilot bit or reamer via the power head and drill rods. This causes the roller cutters of the pilot bit to roll under drilling pressure and generate impact loads. The cutter teeth thereby exert impact, compression and shear forces on the rock to break it apart.
This machine is suitable for various hard rocks with a hardness coefficient ranging from f3 to f12. For extra-hard rock of grade f12 (compressive strength of 200 kg/cm²), custom reamers can be tailor-made to meet rock-breaking requirements. It accommodates a wide range of borehole diameters, depths and inclination angles.
Raise boring machines feature enormous construction potential and a high safety factor, and are applicable to shaft construction projects with varying borehole diameters, depths, and inclinations between 60° and 90°.
Advantages of Raise Boring Machine Construction
The general construction procedure of a raise boring machine is as follows: Construction Preparation → Borehole Center Point Location → Positioning and Straightening of Raise Boring Machine → Pilot Hole Drilling → Installation of Reaming Bit → Raise Reaming Construction → Site Clearing upon Completion
High Safety of Raise Boring Machine Construction
Compared with other construction methods, raise boring machine construction eliminates the need for workers to enter the working face to perform drilling, charging, temporary support and other operations. All operators work at the upper level with better environmental and safety conditions. Workers are protected from falling rocks, water seepage and harmful gas hazards, which effectively prevents safety accidents.
High Working Efficiency of Raise Boring Machine
Raise boring machine construction adopts continuous mechanized operation with fast advance rate. Its working efficiency is 5 to 10 times higher than that of other construction methods. It creates favorable conditions for subsequent construction and delivers remarkable comprehensive benefits.
Excellent Engineering Quality of Raise Boring Machine
The raise boring machine breaks rock mechanically with roller cutters, causing minor disturbance to surrounding rock. The smooth shaft wall facilitates muck passing, ventilation and drainage during subsequent enlarging excavation.
Easy Operation and Low Labor Intensity
The raise boring machine is controlled by hydraulic transmission, featuring simple operation and greatly reduced labor intensity for workers.
