In the 1980s there were punched two short exploratory tunnels in the Czech Rock massive. These tunnels were used to verify a stock of basalt for extraction. One of them is on the northeast edge of rock, directly under the peak and the other is about 80 metres south of the peak. In both cases it is a simple straight corridor without branching and it is a few tens of meters long. Nowadays, it is especially a winter habitat shelter for bats and both tunnels are closed by bars.