How can the tension of a roof bolt be approximated?

The tension of a roof bolt can be approximated by multiplying the torque reading by a specific factor, which accounts for the properties of the bolt and the friction involved in the installation process. In this case, multiplying the torque reading by 40 provides a reliable way to estimate the tension that the bolt is under once installed.

This factor of 40 is derived from empirical studies and practical experience in the field that have determined the relationship between the applied torque and the resultant tension in roof bolts. The use of this multiplier helps ensure that the roof bolts are installed with sufficient tension to effectively support the mine's roof structure, enhancing safety and stability.

Understanding this relationship is crucial for mine foremen, as proper tensioning of roof bolts is essential in preventing roof falls and ensuring a safe working environment for miners.