Rock Boring Services

Raise Boring

What is Raise Boring

Raise boring is the process of boring a raise. A pilot hole is drilled from the drill rig to an underground cubby or tunnel. A reamer head with cutters is then attached to the drill string. The drilling rig at the surface or upper level then pulls tension onto the drill string while rotating, causing the large diameter cutting bit to cut a large hole from the underground tunnel or level to the surface or upper level.

The cuttings are removed as this fall to the ground due to gravity feed. The process sounds simple but requires skilled operators, good quality down hole equipment and powerful drill rigs.

What is Raise Bore Drilling used for?

Raise boring is used to create a circular vertical or horizontal excavation between two existing levels or tunnels in an underground mine. It is mostly used for ventilation shafts from the surface to underground.

Mining

Raise boring is used to drill shafts for ventilation, transferring ore from one level to another, creating silos for storing rock as well as hoisting of rock and ore to the surface. The application of Raise boring in mining also assists in providing access for personnel or material underground.

Energy

These types of holes and shafts are used in Hydro Electric or Pump Storage plants as pressure shafts. Also, it is used for access to underground nuclear storage facilities.

Civil

In urban infrastructure, raise boring is used to collect waste or flood water from streets directing it to an underground tunnel or dispose of. It is also used to access ventilation shafts required in underground metro and rail systems.

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What are the benefits of Raise boring?

Compared to conventional methods of excavation, raise boring has the following advantages:

  • Safe
  • No explosives used
  • No rock fractures associated with blasting
  • Stable circular excavation results with zero damage to the sidewalls of the hole or shaft
  • Accurate hole or excavation
  • Automated operation
  • Cost-effective
  • Fast, efficient and flexible
  • Excavation at various angles or dips
  • Ability to obtain machine data and advance rates client

What are the different diameter sizes that raise bore
machines can excavate?

The diameter size of excavations are dependent on the client’s requirements, type of rock formation or geology and the capability of raise bore machine used.

250mm - 8m

Excavation diameter

180mm - 1,5km

Excavation depth

Watch this video to find out more about horizontal raise boring

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Watch this video to find out more about raise boring Reamer breakthrough

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FAQ

The Raise Boring process
and applications

Category

Conventional Shaft Sinking

Raise Bore

Bottom access required

None required

Access required

Cost

Very expensive

Appropriately costed

Safety

High risk process

Safer

Explosives

Explosives used

No explosives used

Accuracy

Survey as proceed

Accurate using directional tools

Labour

Very labour intensive

Not labour intensive

Advance

1-2 meters a day

5-7 meters a day

 

The concept of raise boring is about 50 years old and is essentially still the same, with changes only related to machine upgrades and bolt-on technologies. The need for bigger, deeper and more accurate holes has become a requirement as machines need to be able to drill to deep holes and ream open large diameters.

 

Contractors need to share machine metrics with clients as they drill on aspects such as meters advance and ground conditions – this is achieved through data loggers. In addition, bolt-on services to ensure rock support, downhole equipment such as the drill rod metallurgical changes, cutting consumable quality and the control of the cutting process has significantly attributed to technological changes over the last few years.

Understanding the geotechnical characteristics and consistency of the rock formation to be drilled through is important as there are different parameters to the different rock formations. It is important to know where the geological consistency changes regarding the brittleness, toughness, and abrasiveness to reduce operational risk and costs. 

Master Drilling manages a large fleet that continuously challenges existing standards, therefore setting the status quo for the industry. Operators need to be skilled, ensuring best practice to deliver quality service to clients. Several hazards such as dropping a reamer head or getting a drill rod stuck during the drilling process resulting in delays and lost costs highlights the importance of operator training.  Mitigating and managing these risks can be achieved through continuous training and replacing operator control for critical tasks with automated functions.   Master Drilling has developed remote operated machines for safer, faster and more efficient operations.

Calculations are conducted based on the depth of the hole to be drilled, the size of the excavation and the type of ground conditions. These factors indicate the type and size of the machine required. Other factors to consider are the available space where the machine will be located the and how to get the required machine to this area.

Master Drilling provides rod handlers and has recently also started providing mobile erectors and remote operated spanners. Through training, operating procedures and technical innovation safety standards are improved.

 

Several of the operations are automated, and the machine automatically shuts down if the machine is operated outside the “safe operation zones”. 

Automation in mining has become imperative for safer, faster and cost-effective operations. Master Drilling is investing in considerable resources to establish reliable remote and automated features for operations and meet clients’ needs and requirements.

The general trend is that mines are getting deeper and are venturing into more unchartered territories. Therefore, raise bore drilling machines must be able to drill deeper, faster and more accurate.

 

Machines must be automated, less labour-intensive and reliable. Underground machines must be mobile, hence large machines are on tracks or crawlers to improve mobility.

Master Drilling continuously invests in research and development as a strategy to differentiate our services from those of others as a result of technical and operational advances.

 

A focus is on cutter life to prevent cutter changes. To ensure that rod handling is easy and quick with the minimum human intervention to reduce risk, machines are automated and provide readings to the operator on infiltration, weight on the bit and other essential matrix.

Master Drilling has released a new user interface with machines, enabling some autonomous functions such as us remotely operating some of its machines.

 

A reef borer is in development to allow for the remote drilling of reed underground without any waste.