Mining roof bolt

Friction bolt is a kind of underground mining roof bolts,also known as split set bolt.

It is an effective solution  in underground mining roof supporting, tunnel construction.

It is a high-strength “C” shaped steel bolt with two parts, a tube and a matching domed bearing plate.

One end of the tube is tapered for easy insertion into a drill hole and the other has a welded ring flange to hold the bearing plate.

With the bearing plate in place, the tube is driven into a slightly smaller hole, using the same standard percussion drill that made the hole. As the tube of the rock bolt slides into place, the full length of the slot narrows, causing radial pressure to be exerted against the rock over its full contact length.

The rock bolt is an effective way to support the rock in underground mining and tunnel construction.

Raw materials of underground mining roof bolt

The raw material is high-strength alloy strip steel,

The  Bolt generally use high-strength steel,

Such as Q235, Q345 and other steel as the main material.

Technical Requirements of the underground mining roof bolt

1, The surface of the bolt body should be flat, without strains, rust and corrosion.The welding seam should be free of cracks, no air holes and slag, not allowed to burn through the bolt.

The palate should be able to move freely on the bolt. Retaining ring interface and pipe seam opening mutual misalignment 170o-190o is appropriate.
2, Retaining ring welded pull-off force ≥ 80kN, the ultimate tensile force of the bolt body ≥ 110kN, the initial anchor force ≥ 25kN / m, plate bearing capacity ≥ 65kN.

 Installation of the friction bolt

1. Drill a hole on the roof or wall using the rock dill.The hole should be 2-3mm smaller than the diameter of the split set bolt.
2. Cleaning:blow out the dust in the hole with compressed ai
3. The bolt is fitted with bearing plate and drive into the hole.

Application of mining roof bolts in underground mining

Friction Bolt is widely used in different fields.

Underground mining,tunnel construction and other civil engineering.

Underground mining:Friction bolt is a common underground mining roof rock bolt,is used to support rock in underground mining.To ensure the stability and prevent rock collapse.

Tunnel construction: It is used to support the surrounding rock and it’s collapse in tunnel construction.

Civil Engineering: Friction bolt is used to stabilize the ground and prevent erosion in civil engineering.

Infrastructure work:Friction bolts are used in some infrastructure work ,such as bridges and dams construction.To provide support the surrounding rocks and soils.

Advantages of rock bolt

In underground mining and some other construction works,friction bolt is common use to ensure the stability of the rock and it’s collapse,due to it’s advantages.

1.The raw material is made of high-strength alloy strip steel;

2.Fast and easy installation.

3, No anchoring agent is needed;

4, High friction between rock and bolt body;

5, High shear and tensile strength;

6, Equipped with high-strength palate, the plate force is uniform;

7. Easier mesh installation

Our stabilizer system will reduce your cost on labor,materials and maintenance.

Specifications

DIA	33mm	39mm	42mm	47mm
Pipe thickness(mm)	1.8-3.2mm(as customer required)
Min. Yield Strenght(KN)	78	88	95	124
Min. Breaking Strenght(KN)	103	116	123	160
Max. Breaking Strenght(KN)	117	132	140	186
Elongation	>16%	>16%	>16%	>16%
Anchoring	4-7tons	5-8tons	5-8tons	6-12tons
Head length	40-50mm

Length of the friction bolt:90cm,120cm,150cm,180cm,200cm,250cm,as your request