EXPANDABLE ROCK BOLT

ONIX UNDERGROUND

EMC EXPANDABLE ROCK BOLTS

The expandable rock bolts are a stabilization device for rock masses in mining and underground works. They are made up of a high elastic limit steel tube, bent into an omega shape, and sealed at the ends with ferrules.

Once inserted into the hole drilled in the rock, which must have a larger diameter than the original diameter of the tube, they expand through the application of water under pressure. This process causes the anchoring bolt to be loaded, and offer immediate support. This is achieved thanks to the action of two types of forces; the first force- a radial pressure perpendicular to its axis along its entire length, and the second force- a frictional force along its entire length.

Perno Expansivo

FIELDS OF APPLICATION

The Expandable Bolts have a wide range of applications in the mining and construction industry. Some of the most common fields of application are:

 Underground mining: to stabilize the rock mass in tunnels, galleries, chambers, and other underground excavations

 Tunnel construction: to secure the cavity during excavation

 Geotechnics: for the stabilization of slopes, rock walls, and other geotechnical structures

EMC ROCK BOLT TECHNICAL PROPERTIES

Onix Underground Expandable Bolt Table Specifications

ONIX TABS

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We offer colour taps to protect the rock bolt when it is inserted to the hole and to identify the lenght of the bolts by the ASTM rules. The colour taps can be customizable with the logo of your company.

EMC EXPANDABLE ROCK BOLT MANUFACTURING PROCESS

The in-house manufacturing process starts with the acquisition of the raw material- we use steel S 355 MC. The steel is shaped by our own profiling machine to the client’s specifications. Due to the machine technology, the roller process is moderate enough that it doesn’t adversely change the properties of the steel. As a result, we obtain an omega shaped tube. At every stage of the manufacturing process, quality is constantly monitored.

Once we have the omega tube, it is inserted in the inlay machine. Like the profiling machine, our in-house inlay machine was built using cutting edge technology with an automated welding process, making it possible to achieve a very high production capacity, which also exceeds our own quality threshold.

The ferrules which are inserted in the tube, are manufactured using complex processes which guarantee the highest quality, making the insertion of the inflation chuck easier and increasing the efficiency of the final product.

Finally, the expandable rock bolts are packed and stored in our distribution warehouse where they are protected from all weather conditions and are ready for prompt worldwide delivery.

From each production lot, we test one bolt per thousand. A random sample is selected for testing by the quality control department. Traction and swelling tests are done and the results are recorded. In addition, we monitor all the orders and correlate the corresponding results of the quality testing with each order. In this way, if there are any incidents, our response time is quick and efficient.

INSTALLATION PROCESS

WE PROVIDE EXPANDABLE ROCK BOLTS TO BE USED IN TUNNELING AND UNDERGROUND HARD ROCK MINING ENSURING THESUCCESS AND SAFENESS OF THE EXTRATION AND EXCAVATION PROCESSES
  1. Drill the hole in the rock with a depth slightly larger than the bolt
  2. Insert the expansion bolt through the hole manually or automatically
  3. Inject pressurized water to expand the bolt and make contact with the walls of the hole
  4. Wait for the necessary time for the bolt to fully expand and remove the inflation pump nozzle
Installation completed

ADVANTAGES OF THE EXPANDABLE ROCK BOLTS

The Expandable Rock bolts has several distinctive advantages in underground mining and construction applications to other ground support elements. Below are some of the main advantages:

High strength: the expandable rock bolts are highly resistant due to their design and the material used in their manufacture, making them suitable for applications that require a high load capacity.

Easy installation: the expandable rock bolts can be installed quickly and easily, reducing downtime and labor costs.

Flexibility: the expandable bolts are flexible and can adapt to different geological and terrain conditions.

Compatibility with other systems: the expandable rock bolts are compatible with other anchoring systems, allowing for greater flexibility in selecting support systems.

Safety: the expandable rock bolts are safe for use in underground environments, as they do not require any chemical accelerant during installation and achieve load immediately.