Implementing a suspension design for coal mine roadway support

Suspension of the immediate roof is one of fundamental ground control strategies available to a coal mine engineer. Correctly implemented suspension offers the greatest improvement in roof stability and greatest reduction in longwall risk. In some circumstances an alternative strategy based on the reinforcement of bedding parting may be more appropriate. For the control of maingates ahead of retreating longwall faces the ideal suspension support (if required) consists of angled, partially debonded, medium-length tendons installed as far behind the development face as possible. For situations where the roof may be subjected to tensile horizontal stress, immediate support by equally spaced short vertical tendons is required. The step away from fully-grouted tendons improves their survivability during the onset of compressive failure in the roof, minimises the risk of isolated loading, and allows a more robust TARP for roof movement. All suspension systems require a sling or truss between the suspension elements.