Lyle, RR 2017, 'Considerations for large-diameter raiseboring', in M Hudyma & Y Potvin (eds), UMT 2017: Proceedings of the First International Conference on Underground Mining Technology, Australian Centre for Geomechanics, Perth, pp. 581-595, https://doi.org/10.36487/ACG_rep/1710_47_Lyle (https://papers.acg.uwa.edu.au/p/1710_47_Lyle/) Abstract: For over 50 years, raisebore drilling technology has been successfully employed for vertical mine development in mines around the world. In the early days, raiseboring was limited to small-diameter (< 2 m) raises; but with time the method has evolved so that boreholes greater than 5 m are now routinely completed without incident. One important evolution is the Rotary Vertical Drilling System (RVDS) to maintain verticality of boreholes. This technology enables the effective development of hoisting shafts using accurately controlled vertical raisebored excavations. Mine planners must now consider using raiseboring techniques not only for small-diameter raises, but for largediameter vertical development, including ventilation, secondary egress and hoisting shafts. This paper provides insight into the important considerations for large-diameter raiseboring projects. This includes an examination of methods to assess geotechnical risk for large-diameter raiseboring projects, including the commonly employed McCracken and Stacy (1989) method. Examples of recent, prominent large-diameter raiseboring projects are also profiled to show the diverse range of projects which have been able to take advantage of modern raisebore technology. Keywords: vertical mine development, raiseboring, mine planning, borehole hoisting