ABSTRACT
The development of Swedish rock mass roof support by use of rock bolting technique is briefly reviewed. It is shown that the concept of the natural arch -although until lately not verified by measurements – has directed Swedish practice towards the use of slack grouted bolts. The general ideas behind this choice are discussed. It is suggested that calculation methods now prevailing are not sophisticated enough to describe the true rock mass behaviour in the formation of natural roof arches. It is further suggested that roof support with slack grouted bolts has a wider application than is generally acknowledged at present by rock mechanics theorists. Finally, some conclusions are recommended to be brought up for discussion at the Abisko symposium.
