Shear-bond strength testing of thin spray-on liners

TSL materials for ground support were initially intended to be used as an alternative to mesh or shotcrete. The first trials on TSL technology were initiated in Canada in the late 1980s (Archibald et al., 1992). Early research led to the development of a polyurethane based product. In the 1990s, numerous advantages in terms of speed of application and minimizing transportation of materials were realized. In the late 1990s, applications included a hybrid polyurethane/polyurea based mixture (Tannant, 2001). Meanwhile in 1996 in South Africa, a latex-based product was developed and tested, and then later another product followed (Wojno and Kuijpers, 1997). Researchers in Australia have also been exploring the use of TSLs for rock support and have conducted field tests in Western Australia. Many products have been tested so far and it was found that most did not possess adequate physical or chemical properties. Although the production of a number of products has been stopped and their names are not referred to any longer, newer products are continuously developed and introduced. Recent developments on TSL support continue to receive increasing attention by the mining industry around the world due to considerable operational benefits, with the potential to greatly reduce mining costs. There were about 55 mines around the world in 2001 that were considering the use of TSL for rock support, and this number is increasing steadily. The greatest interest is in North America, Australia, and South Africa (Tannant, 2001).