The Mária Adit near the village of Merník
National Cultural Monument The Mária Adit, located between the villages of Čičava and Merník in the Vranov District, once belonged to the area of the local mine for the ore mineral cinnabar, which contains mercury. Mercury ore mining is the second most important after opal ore and is also the oldest mining activity in the Slanské vrchy mountains.
Mercury could be mined near Merník as early as the 18th century. The first records of industrial mining date back to 1830. Mined cinnabar was burned in clay vessels called "rétory", which were inserted into the coals in the forest and in places where there was quality firewood. The reason why mining was stopped in the late 1940s was the low profitability.
Despite the fact that the entrance and the mine itself were covered, the tunnel about 450 meters long can be seen from the outside. It can be reached by a forest road. You will find it in the direction from Čičava to Merník - about halfway to the left.