Rock Bolts – Solid Bar
| Physical Properties | Minimum | Typical | ||
|---|---|---|---|---|
| Yield Strength | 540MPa | 160kN | 615MPa | 185kN |
| Tensile Strength | 660MPa | 195kN | 725MPa | 215kN |
| Calculated Shear Strength | 120kN | 130kN | ||
| Elongation (After Fracture) | 16% | 21% | ||
| Mass Per Metre | 2.47kg | Cross Sectional Area | 300mm2 | |
| Major Bar Diameter | 22.1mm max | Rolled Thread | Continuous coarse | |
| Bar Diameter | 20.0mm | |||
Key Features
- The "posimix" bolt is manufactured with the addition of a specially designed spring wire attached to the up hole end of many of DSI Underground's rock bolts.
- The "posimix" bolting system was designed to assist in the installation of rock bolts with chemical anchors in larger diameter holes (35-38mm) by providing:
- substantially enhanced mixing of the chemical anchors,
- Increased load transfer capabilities,
- the ability to be installed with a face jumbo as well as hand held machines.
- The "posimix" device centralises the bolt in the hole allowing an even distribution of the chemical anchor around the bolt. It also acts as an Archimedes screw pump forcing the chemical towards the back of the hole, assisting in mixing whilst consolidating the anchor for improved load transfer properties.
- In addition to improved mixing properties the "posimix" device also tends to pump the plastic skin of the chemical anchor to the back of the hole which eliminates the ‘gloving’ effect.
- Most DSI Underground conventional chemical bolts can be manufactured as "posimix" bolts and supplied to suit either left or right hand bolt rotation.
- Recommended hole size is 35-38mm in diameter.
- Corrosion protection may be provided by hot dip galvanizing or alternative coatings.
- Australian Patent Number 717939 is applicable to the design of DSI Underground "posimix" bolts and components.
Installation Guide Lines
- The rock bolt hole is drilled as per mine support designs.
- Hole depth is critical. Hole depth should be shorter than the bolt to allow for the height of the washer and nut.
- After insertion of the resin anchors the bolt is rotated through the anchors while being pushed to the back of the hole.
- In the case of full encapsulation, anchors of different setting times are often used and the higher speed anchor is to be inserted first followed by the slower speed anchors.
- It is important to follow the resin anchor recommended mixing and hold times as printed on the resin anchor cartons. DO NOT OVER MIX.
Standard Lengths & Packaging
- Standard bolt lengths range from 1500 to 3000mm in 300mm increments.
- Non-standard lengths are available by negotiation.
- Bolts are packaged in bundles with threads protected by heavy duty polyethylene bags.
- Bolt fittings, such as nuts, anti-friction washers and dome balls, are supplied fitted to rock bolts in the configuration requested.
Notes
- Only DSI Underground Rock bolt components should be used to enable the optimum performance of the bolt system to be obtained.
- Assistance should be sought from DSI Underground's Technical Services Engineers in selection of the correct "posimix" bolt for the application together with its product code.
- DSI Underground Mining Products Division is Quality Assured to ISO 9001:2015, Registration QMS 41328.
