Iron-ore and mercury adit in the Žakarovce mining district near Gelnica, active from at least the 16th century and served by Slovakia's first rack railway from 1884.
Štôlňa Zuzana is one of several named adits in the Žakarovce iron-ore and mercury mining district on the slopes of Žakarovský vrch and Špicatý vrch, situated approximately four kilometres from Gelnica in the Hnilec valley of eastern Slovakia. Mining on these slopes began no later than the 14th to 15th centuries, targeting mercury ore (cinnabar) and later siderite iron ore alongside copper and precious metals. The district grew significantly in the 19th century after the Těšínsko-třinecká ironworks company, part of the Albrecht Habsburg estate, acquired the mines in 1872.
Between 1884 and 1899 a rack railway — the first of its kind in Austria-Hungary — connected the adits of the Žakarovce area, including Štôlňa Zuzana, to the smelting facilities at Máriahuť in the Hnilec valley. When the rack railway was closed, roasting furnaces were constructed at Štôlňa Zuzana itself. By the mid-20th century the deposit was substantially exhausted, and extraction declined to eventual closure.
The Žakarovce mining district, within which Štôlňa Zuzana is situated, forms part of the broader Gelnica mining region of the Spišsko-gemerské Rudohorie mountains. The town of Gelnica received mining-town status in 1264 and was a royal free mining town from 1276, serving as the leading centre of the Association of Upper-Hungarian Mining Towns from 1487. Žakarovce itself is first mentioned in writing in 1336. Mining activity on the slopes of Žakarovský vrch and Špicatý vrch is attested in writing from the 16th century, when the extraction of mercury ore (rumelka, cinnabar), copper, and precious metals is recorded in the area known as Krompašský vrch.
The Žakarovská Hrubá žila (Žakarovce Main Vein) contained siderite and ranked among the most significant hydrothermal iron-ore veins in Slovakia. Extraction became increasingly focused on siderite iron ore as earlier commodities declined. The working of iron ore in the district expanded substantially in the 19th century.
In 1872 ownership of the mines passed to the Těšínsko-třinecká železiarska spoločnosť (Těšín–Třinec Ironworks Company), which formed part of the estate of Archduke Albrecht of Austria-Habsburg. Under this ownership, the company invested in infrastructure to improve ore transport from the hillside adits to valley-floor processing facilities. The adits active in this period included Kálman, Anton, Mária, Viliam, Rudolf and Zuzana.
In 1884 a rack railway — the first of its type built in Austria-Hungary — was opened to carry ore from the Žakarovce adits along the Žakarovský potok valley to Máriahuť (today part of Gelnica) in the Hnilec valley, a distance of approximately four kilometres. This railway operated until 1899. Its closure was directly connected to the decision to build roasting furnaces (pražiarenské pece) at or near Štôlňa Zuzana, enabling ore treatment to be carried out at the mine itself rather than requiring transport to the valley floor.
By the mid-20th century the deposit was largely exhausted. Extraction declined and the various industrial processing facilities in the area closed. Today, apart from mining landscape features — adit portals, waste tips, surface subsidence hollows, and spoil heaps — the former industrial complex has largely disappeared, with only some residential buildings from the mining period surviving.