Valachov Natural Monument and Historic Mining Landscapes of Central Bohemia, Czech Republic

Valachov is best known as the type locality for the rare mineral slavíkit, a secondary sulfate mineral that forms yellow-green crusts and coatings on pyrite-bearing shales. It is also notable for its assemblage of other secondary sulfur minerals, including copiapite, jarosite, melanterite, halotrichite, fibroferrite, natrojarosite, szomolnokite, gypsum, and čermíkit, which together make it one of the more mineralogically distinctive small protected sites in the Czech Republic. A second important theme is the site's mining history. The hill preserves short adits and an 18-meter shaft that document lead mining in the 16th century and pyrite extraction in the 1870s, ending only when the great Bohemian flood of 1872 destroyed the on-site processing equipment. This combination of mineralogical and industrial-archaeological value within an otherwise wooded Central Bohemian hill makes Valachov stand out among small natural monuments.

The oldest documented human activity at Valachov is lead mining, with the first written record dating to 1543, when ores were extracted from the hill. A later wave of mining took place in 1871 and 1872, when pyrite was worked on the slope from a deposit lying at the contact between black shales and spilite. Ore was processed on site in the valley below, where a steam crusher and a forge for tool sharpening and repair operated; refined pyrite was then sent onward to Kolín for further processing. This industrial activity came to an abrupt end with the great Bohemian flood of 1872, which destroyed the operational equipment.

In 1926, Rudolf Jirkovský and F. Ulrich identified a new mineral species here, which they named slavíkit in honor of the prominent Czech mineralogist František Slavík. The locality has retained its scientific importance ever since as the type locality for this rare secondary sulfate mineral. The site was formally designated as a protected area, a přírodní památka (natural monument), on 29 November 1977 by the Regional National Committee of the Central Bohemian Region, consolidating its protection for both its mineralogical and ecological values.

Valachov is a rounded hill rising to about 413 meters above sea level, set within the Plzeň Upland (Plaská pahorkatina) and specifically in the Kralovická pahorkatina subunit, Radnická vrchovina area, and Skryjská vrchovina podokrsek. The local terrain consists of gently undulating forested hills typical of the Central Bohemian countryside west of the Berounka River, with the protected area confined to the western slope of the hill.

The hill itself is a geological klippe built of Neoproterozoic graywackes and pyritic shales, locally capped by spilite, which gives parts of the slope a rocky and exposed character in contrast to the surrounding woodland. Three sides of the hill are encircled by the Tyterský potok, a small stream that defines the lower edge of the slope and shapes the local relief. The protected site lies within the much larger Křivoklátsko protected landscape area, where similar forested hills, valleys, and waterways form a continuous mosaic of protected Bohemian countryside.

Vegetation on the protected slope is dominated by fragments of pine forest and stunted tolit oak woodland, two plant communities adapted to dry, rocky, and nutrient-poor conditions. The forest cover is relatively open in places, allowing light to reach the rocky outcrops and supporting specialized species that would not survive in denser forest. The exposed rock surfaces host thermophilous plants, and the combination of pines, oaks, rock outcrops, and former mine workings creates a mosaic of habitats within an area of only a few hectares.

The site's ecological importance is closely tied to its unusual combination of forest, rock, and abandoned mine features. The two short adits and the shaft near the summit provide sheltered environments used by bats, while the slope and surrounding woodland support herpetofauna and ground-dwelling invertebrates. Within the broader Křivoklátsko landscape, Valachov functions as a small but ecologically distinctive refuge, with its dry, rocky forest and post-mining habitats contrasting with the moister river-valley ecosystems that dominate much of the surrounding protected landscape area.

The most distinctive wildlife value of Valachov lies underground in its two preserved mine adits, which are used as winter roosts by bats. Four bat species have been documented hibernating in the tunnels: the western barbastelle (Barbastella barbastellus), the greater mouse-eared bat (Myotis myotis), the grey long-eared bat (Plecotus austriacus), and Natterer's bat (Myotis nattereri). These underground shelters make the site ecologically valuable even though it is very small in surface area.

Above ground, the protected slope supports a community of amphibians and reptiles typical of Central Bohemian forest-steppe mosaics. The fire salamander (Salamandra salamandra) occurs in the marginal parts of the area, while the common toad (Bufo bufo) is widespread across the whole site. Reptiles include the sand lizard (Lacerta agilis), the slow worm (Anguis fragilis), the grass snake (Natrix natrix), and probably also the common European adder (Vipera berus). In the surrounding forests, two strongly threatened bird species nest close to the protected area: the Eurasian pygmy owl (Glaucidium passerinum) and the European honey buzzard (Pernis apivorus); eagle owls (Bubo bubo) have been confirmed breeding directly within the natural monument. Two specialized ground spiders, Zelotes puritanus and Zelotes exiguus, have also been documented here, and the red squirrel (Sciurus vulgaris) is common throughout the area.

Valachov is protected primarily for its mineralogical and geological significance rather than for landscape beauty. Its status as a type locality for slavíkit and its unusually rich assemblage of secondary sulfur minerals make it a reference site for Czech mineralogy. The protection of these minerals, formed by the oxidation of pyrite in old workings, requires preserving the abandoned adits, the shaft, and the exposed pyritic shales from disturbance, and also maintaining the broader slope conditions that control weathering and mineral formation.

Although small, the site is ecologically meaningful because of the combination of rocky grassland, dry pine and oak forest, and abandoned mine workings, which together sustain protected plant species and provide essential bat hibernacula through the winter. Its location within the larger Křivoklátsko protected landscape area reinforces its conservation value by placing it inside one of the most strictly protected forest and river complexes in the Czech Republic, managed centrally by the Agency for Nature Conservation and Landscape Protection of the Czech Republic (AOPK ČR) through its Central Bohemia regional office.

Valachov's standout features are its mineralogical rarity and its preserved mining heritage. The hill is the type locality for slavíkit, and the combination of pyrite oxidation products found here places it among the most notable small mineralogical sites in Central Bohemia. Equally distinctive are the surviving historical mining features, including two short adits, a deep shaft near the summit likely connected with medieval lead mining, and visible pyrite workings from the 1870s that ended abruptly with the great Bohemian flood of 1872.

Ecologically, the protected slope functions as a compact biodiversity pocket: dry pine and oak forest, rocky outcrops with Jovibarba globifera and juniper, hibernating bats in the adits, breeding eagle owls on the hill, and a strong presence of reptiles and ground spiders. Together, these features make Valachov a small but unusually rich intersection of geological, industrial-historical, and ecological values within the Křivoklátsko landscape.