The rock at Sala mine is mainly a dolomite mineral, and the underground is a myriad of some 20 kilometres of drifts, most of them today water filled to a depth of 155 meters. Further, a complicated system of tunnels feeding the water turbines, driving the hoist machineries at Queen Christina’s and Carl XI’s shafts were built during the 1800th century, further adding up this underground mess...

The mine masters at Sala were somewhat conservative in their use of dynamite and other types of modern explosives. Until as late as 1880, most of the drifts (and even the shafts) were driven by the ancient means of using fire. As opposite to drifts driven by explosives, this method gives the rock wall an overall smooth appearance.

Today, a small part of the mine is open to the public - it is a nice experience. However, an even nicer experience can be found at other sections of the mine - outside the "common path" :)
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