Student Number : 7439270 - MSc research report - School of Mining - Faculty of Engineering and the Built Environment / In tabular mining, common in South African gold and platinum mines, the removal of the tabular ore body by mining operations leaves behind excavations known as stopes. These stopes form the production areas of a mine and have to be supported in order that a safe working environment is created. Stopes generally have widths of close to a metre but, in some areas and on certain reefs, may be much wider. Prior to the 1980s, a combination of in-stope pillars and timber was used to support these stopes, but innovations from the 1970s have produced grout packs as a viable support option. These packs are cast in situ through the use of cemented classified tailings gravitated from surface and placed in reinforced geotextile bags at the stope face. As these packs cure and become rigid they are able to bear load when compressed by stope closure. In this way, the packs keep the working areas open. To quantify the load-bearing capacity of grout packs, a range of sizes and designs was tested in a laboratory press and, thereafter, a select few were tested underground. Initially, two aspects of grout packs that had not been adequately quantified previously were addressed. These were: the in situ load / compression characteristics of different forms of grout packs; and the relationship between laboratory test results and in situ performance. The laboratory test programme was extended to allow for an investigation into methods of improving the yieldability of grout packs and the possibility of using them to replace in-stope pillars. It was found that the factors that most affect the initial strength and post-failure characteristics of a grout pack are: the grout strength; the amount and type of steel reinforcement; the inclusion of ancillary columnar support; and the height and diameter of the pack. It was also found that grout packs could be used to replace in-stope pillars, but that pack strength and spacing should be conservatively calculated before implementation. A provisional relationship between the behaviour of packs tested in a press and those placed underground was determined.