Abstract
Supporting of underground hanging-walls is an important task that ensures a safe working environment and a continuous opening in underground mining operations. Underground stope support systems such as yielding pencil props, packs, tendons and backfill are used to stabilise hanging-walls in excavations to reduce or eliminate falls of ground and rock-bursts. The brushingoff of the pod end of an installed E. grandis pencil prop is the initial yielding part of the support unit under load. This failure mechanism allows inelastic hanging-wall to converge or vertically dilate while the support unit maintains contact with the rock unit without losing its support integrity (i.e. it does not buckle). Higher Moisture Content (MC) in yielding pencil props allows the props to fail according to the expected mechanism. Tonnes of timber products are wasted annually due to severe cracking / checking during the storage phase. Physical deterioration in a form of cracks of more than 10 mm wide and longer than 1/3 of the longitudinal dimension of the yielding pencil prop are criteria used by timber units’ suppliers to reject yielding pencil props...
M.Ing. (Engineering Management)