IM 2020 July/August 20 - Page 48

GROUND SUPPORT Minova's UniPass Bolting Technology is described as an innovative ground support system for one and two step rock bolting, which combines Minova hollow bolts and self-drilling anchors with its patented bulk injectable resin, CarboThix There has been a big move in the ground support industry in recent years to offer pumpable resin systems for underground rock bolting, delivered via dedicated mechanised bolting rigs. Orica-owned Minova told IM that it is introducing its UniPass Bolting Technology – described as an innovative ground support system for one and two step rock bolting, which combines Minova hollow bolts and self-drilling anchors with its patented bulk injectable resin, CarboThix. By combining these two products, Minova says it has created “a unique rock bolting solution that has been engineered to suit even the most demanding requirements of hard rock underground mining and tunnelling environments.” The use of pumpable resin and hollow bolts is quickly gaining traction in underground operations due to the ease of use, clean operating environment, improved safety, and the ability to provide instant ground support, enabling the miner to move faster. Mines are extracting ores deeper than ever before, resulting in higher rock stresses, potential increase of convergence, dynamic events, and rock bursts. There is an increased demand on ground support applications, the products used and the safety of operators. Existing rock reinforcement solutions can be prone to limited ductility, installation difficulties, especially in broken ground and limitations on the efficiency and productivity of installation processes. Minova’s Peter Assinder, Global Head of Sales, Marketing and Technology comments: “Mining companies are looking to decrease such risks and increase productivity by speeding up the bolting cycle and introducing mechanisation and further automation options. OEMs and their contractors are also looking to enhance the quality of materials used in mines to deliver installation consistency.” For the last eight years, Minova says it has been developing a solution which it says provides answers to the requirements for increased automation, greater mine mechanisation, improved productivity and moving miners away from the working face. “Working with a major OEM of mechanised bolting equipment, Minova further developed their industry leading pumpable resin CarboThix and self-drilling hollow bolts to enable single pass installation of ground support, which Minova has termed UniPass.” Safe, deep mining Paul Moore looks at key developments including the use of pumpable resin with bolts & SDAs for rock reinforcement The OEM company that Minova worked with to develop the UniPass system is Epiroc, with the system designed to work with its Boltec M and Boltec E models. Last year Peter Bray, Global Product Manager, at Epiroc, had this to say: “An important factor to achieve a workable rock reinforcement solution is to have a system where the bolt design, bonding agent and bolting rig all work together to provide a robust and reliable bolt installation. To this end, Epiroc has worked hand in hand with a leading bolt and chemical supplier to create a bolting system that addressed the issues faced with long-term bolting in poor ground conditions.” The result of this work is an integrated pumpable twocomponent resin system that can be used with a Self-Drilling Anchor style bolt in tougher ground conditions or, alternately, with a one-step or twostep hollow bolt in both hard and moderate rock. A major part of any new development process involves extensive laboratory and mine site testing. Minova was the material supplier for the ground control work package of the EU funded Horizon 2020 Sustainable Intelligent Mining Systems (SIMS), a 3-year program from 2017 to 2020, to demonstrate new technologies for the mining industry. Minova’s hollow bolt and pumpable resin technology was extensively and successfully tested on Epiroc Boltec machines at LKAB’s Malmberget mine in northern Sweden as part of the SIMS work. Assinder comments: “The results surpassed the benchmarks set by the work program in terms of number of bolts installed per shift. The work undertaken during SIMS further allowed Minova to develop and fine tune the bolts and resins and installation accuracy and consistency, including optimum mixer units for the resin across a range of operating environments and approved greases to flush the bolting system after each bolt installation.” The company adds that it is important to note that supporting materials and processes are almost as important as the bolt and grout materials, to ensure consistent quality of installation. “Minova’s static mixers and greases ensure that the two-component resin is mixed and installed correctly for every bolt installation. Additionally, an extensive testing program, including on mine environmental monitoring and laboratory testing provided extra confidence concerning the structural and environmental stability of the resin.” A series of dynamic drop tests undertaken in Europe and Canada further proved the performance of the hollow bolts in dynamic environments for a number of bolt and resin configurations, thus providing confidence to the mine customers that Minova’s new technology is appropriate for their operations. Minova’s portfolio comprises Static, Yielding and Dynamic Hollow Bolts and three main CarboThix resins (Standard, Fast and Rapid) to provide an all-inone bolting system that has been engineered to suit the most demanding requirements of underground mining and tunnelling environments. The products offered are designed to improve installation times and to address hole collapses when used in fractured ground. It is a flexible system that features a load-bearing hollow bolt that is encapsulated by a resin grout body. All bolts are available with or without welded sacrificial drill bits to allow for both one step and two step bolting processes. The welded on drill bit has been specifically designed and manufactured to allow a reduced borehole annulus, lower resin consumption, improved load transfer, shortened drilling time and guaranteed performance (no bits breaking or spinning-off during installation) whilst providing additional anchorage capacity. Minova manufactures a wide range of grout solutions for rock bolting applications. UniPass bolting technology introduces CarboThix, its 46 International Mining | JULY/AUGUST 2020