1. IntroductionThe purpose of rock support and reinforcement is toensure excavations remain safe and open for their intendedlife span. The effectiveness of a reinforcement strategy isimportant for two main reasons: these being safety topersonnel and equipment, and achievement of the mosteconomical access to extract ore. For a particular rockmass, a stabilization scheme capable of matching theexpected behaviour is selected based on an assessment ofthe likely failure modes predicted from the interaction ofan excavation (geometry and purposes), the network ofgeological discontinuities, weathering and the loadingconditions from stress and blast damage [1–4].In most underground mines, the primary form ofexcavation stabilization is provided by a pattern of rockbolts installed within the rock mass. This is complementedwith the use of passive support, such as that provided bymesh or shotcrete, in order to provide surface restraint atthe exposed excavation boundaries.The reinforcement controls the overall excavationstability through keying, arching or composite beamreinforcing actions [5], while the mesh and/or shotcretesupports the small loose pieces of rock that may detachbetween the rock bolt plates [6,7].In general, a stabilization scheme cannot be selectedwithout consideration of the ground support drillingequipment available at a particular mine site. A modern,optimal strategy would consist of mechanized installationof reinforcement and support in a single pass in order toincrease productivity and reduce exposure of personnel andequipment during installation.2. Mechanized resin anchored bolt installationOver the last decade or so, jumbo-installed, 45mmdiameter galvanized and black steel friction bolt stabilizershave become the preferred form of reinforcement inunderground hard rock mining in Australia [8,9]. Thishas been mainly driven by a desire to achieve fastdevelopment rates and low costs in order to allow theextraction of low-grade orebodies. In more recent years, asthe mining operations are getting deeper and the rockmasses are becoming highly stressed, other reinforcementschemes such as fully encapsulated resin anchored bars arebeing considered as an alternative to friction bolts for long-term reinforcement [10–13].The typical bolts being used in the underground hardrock mines have been modified from the bolts used in thecoal mining industry. The modifications have beennecessary due to the need to drill larger hole diameterswith the type of equipment used in the hard rockmetaliferous mines. The modification is mainly in the formof paddles or the use of a spring welded on to the endsection of the bolts. Fig. 1 shows the anchor sections for a24mm Posimix bolt with spring arrangement and a 27mmSecura bolt showing a paddle arrangement. The Posimixwire is 3mm in diameter and has a length of 500mm. Thepaddle width is 29.2mm and they have been sheared intothe end of the bolt for the purpose of mixing resin.Nevertheless, the introduction of mechanized resinanchored bolting using jumbos has been difficult toimplement economically due to the high cost of resintransport and storage: this requires the use of refrigerated