ABSTRACT
Rock bolting is essential means of supporting underground workings and that is why so much concern is paid for research and development work in this field. The increasing depth of workings and mechnization in mining technics sets new requirements to supporting elements. To find an effective type of support for each case rises though several questions which one cannot find an unambiguous answer to. One of the basic problems is the long term performance of the supporting elements. How effective support the rock bolts can provide after one year or ten years or fifty years. The type of rock bolt chosen should work effectively over the life-time needed.
The experiments have shown that very much attention has to be paid on installation and control in the supported areas. Corrosion can cause damage on steel bars and tubes but it is not so rapid phenomen that it would cause any major problems in temporary workings. When permanent workings are concerned then the corrosion has to be taken into account.
Most of the accidents caused by falling rock have happened before supporting the working area properly. On the other hand proper supporting can seldom be done immediately after blasting or after removing the rock. But some kind of first aid which would then be part of the final support also might be the answer to reduce the number of accidents.
