ABSTRACT
The paper describes some guidelines for rock bolt design based on experience from the Boliden Mines. Spot bolting is the most common method of rock support in Sweden. Bolt placement is based on judgement of local rock conditions. However, rock bolt support design should not be based on technical grounds only. Economic aspects should be considered by taking into account the economic risks of a possible failure or production disturbance. It is shown that pattern bolting is preferable to spot bolting under difficult rock conditions by establishing the cost-benefit relationship of pattern bolting for the most important support cases. Guidelines for the selection of bolt length and bolting patterns are given.
