THE CABLEBOLTING CYCLE - UNDERGROUND SUPPORT ENGINEERING

Cablebolts are an important support component in modern underground mi nes. If an optimized cablebolt system is to be achieved, it is insuffi cient to focus on cablebolt layout design or on cablebolt installation in isolation. Cablebolt support like all engineered systems, requires a holistic approach, encompassing integrated elements of design, impl ementation and verification. The ''Cablebolting Cycle'' described in t his paper incorporates these components along with related tools and p rocedures which should be used together to ensure effective and effici ent cablebolt support. Design involves the consideration of demand, ca pacity and constraints as outlined in this paper. The demands imposed on the support system by the rockmass response to excavation under the combined action of stress and gravity must be matched to the capacity of the cablebolt array. The cablebolt system capacity is a function o f the component strengths of the steel strand and the bond (load trans fer) and by the deformation response and retention characteristics of the system. The design is bounded by operational and economic constrai nts. Implementation of the cablebolt array can then proceed and must i nclude appropriate protocols of communication training and quality con trol in addition to both general and site specific installation proced ures. implementation will be discussed as the sum of these components. The cablebolt system as designed and installed must be verified after implementation, and during and after mining to ensure adequacy and ef ficiency. Observation instrumentation and engineering feedback techniq ues for design improvement will be summarized in this paper. The infor mation presented in this paper represents a very abbreviated version o f much broader concepts, procedures and design charts, presented in a practical cablebolting handbook by Hutchinson and Diederichs (1996).