Underground mining began in the Czech lands at the turn of the 13th and 14th centuries. The tools used to create these mines were mainly hammers and picks and where suitable, fire‐setting, which made the rock easier to break away. With these basic tools the work was arduous and slow. In a six‐hour shift and against a mine wall measuring 2 x 1m only about 2.5cm of rock would be broken away; for this reason the mine shafts were often just large enough to crawl through. Hammers and picks were used until the mid‐18th century. The first documented use of gunpowder to be used in mining dates back to 1627 in Banská Štiavnica in what is now Slovakia, and from there it gradually spread to other countries.
Mine shafts dug out using hammers and picks can be identified by the distinct grooves on the walls. We can see these grooves along the whole length of the Johannes mine shaft and in some sections of the mine chambers. The unique position of the hammer and pick in the mining industry is demonstrated by the fact that the crossed hammer and pick has symbolized mining since the 12th century.