The Raise Boring system comprises 02 main stages (pilot and reaming) it is necessary to have 02 levels, chamber RB (Higher Level) and bottom (Lower Level). The successful introduction of machinery ¨Raise Borer¨ has required years of engineering to achieve optimal drilling process.
- The biggest advantage is SAFETY due to reduced exposure and risk, compared to the existing danger in the construction of a vertical hole.
- Greater speed in implementing the hole.
- Better finish, strong and stable wall performed with the conventional system.
- Reducing cots in the medium and long term.
- The use of explosives is not necessary.
- The system can drill large diameter in long lengths at an angle between 45-90 degrees.
This process is the most important of the processes associated with Raise Boring system because it will depend on the success to complete a drilling Raise Boring. The factors that have to be checked when the pilot drilling include:
Drill pilot deviation, geological fault, groundwater, rock swells and landslides of the rock mass. Our machines at all times ensure the accuracy of the hole, resulting in lower drilling costs.
The selection of the drill, operating parameter, stabilization and hole cleaning are some of the variables that operators must meet to ensure the accuracy of the pilot hole.
PILOT BIT (TRICONE)
Most pilot holes are drilled with a typical pilot, which consists of three arms drill, each one has a cutter with inserts of tungsten carbide (cone), welded to form one piece with the appropriate diameter for drilling with the Raise Borer. There are 03 types of pilot bit that are classified as:
- Unsealed bearings.
- Sealed bearing.
- Bearing and sealing bushing.
The Reaming process is a way to cut rock through rotation and pressure. The reamer is pressed with power against the rock, as it rotates. Approximately the advance is from 0.3m to 0.12 mm per revolution of the reamer, depending on the characteristics of the rock to be drilled.
The rock is crushed to a fine powder and compressed in the area of contact between the carbide insert cutters and the rock surface. Cracks are formed from the point of contact to the dropping the rock between the contact points as thick chips. As a result of cracks in the rocks, along with more pressure trajectories of carbide inserts side chipped the surface in these areas.
Consists in sustaining the shaft walls with shotcrete, this process is performed with a robotic system from the upper level to the lower level. To control this process infrared cameras and laser equipment are used.
It is the coating with steel rings of the raise-bored shaft walls to face up the instability of the drilled ground. When the raise-bored shaft is completed, the drill string is lowered and an adapter ring (like a Chinese hat), which will hold the first steel ring, is connected. The coupling between rings is done with bolts and if necessary can be applied welding.
TUMI with the vision of continuous improvement that always pursues, has successfully achieved the insertion in the mining market of the SBM 400 SR machine, which in addition to the benefits of traditional RB has the following advantages:
- The entire machine and crawler can be operated by remote control respectively.
- No concrete pad needed.
- A smaller work station than convectional Raise Boring.
RAISE BORE OVERHAULING
Whether you are looking small for repairs or a complete rebuild of your raise bore equipment, TUMI has the experience, personnel, and necessary equipment to do, because we manufacture all our own equipment and parts and our vast experience in the maintenance of RB equipment.