The Gj0vik Olympic Mountain Hall is the world's largest underground
cavern for public use and was created primarily to facilitate the ice
hockey tournaments for the 1994 winter Olympics in Norway. The
cavern has a span of 61 m, is 91 m long and is 25 m high. Ordinarily,
rock caverns have a span width of 15 to 25 m, however, temporary
mining caverns of up to 60 m have been excavated and natural caves with
even greater dimensions occur. The Gj0vik Olympic Mountain Hall is
unique as it is for public use with a capacity for 5800 spectators. Blasting was conducted with a high production rate at normal costs due
to detailed planning and strict supervision of each round. The initiation
system and vibration monitors were the main tools to control vibration
levels and to facilitate a high production rate. It was of utmost
importance that the rock remaining in the roofs and walls was of high
quality after blasting to avoid rock fall, rock slides and excessive
maintenance work.