According to local tradition, the story begins in the eighth century, when copper from these mountains was donated for the construction of the Great Buddha at Todai-ji in Nara. The original workings are believed to have been located in what is now the city of Nose in Osaka Prefecture, with local residents drafted as laborers and supplied by the provincial government of Settsu. Documentary evidence from that era is thin, but reliable records pick up the thread in 1037 with the establishment of the Nose copper mine. By 1279, the operation had grown large enough that farmers from surrounding manors and public territories were organized into a labor force, binding the copper mines to the villages around them in a relationship that would persist for centuries.

Mineral wealth has a way of attracting swords. During the Heian period, the great warrior Minamoto no Mitsunaka built his residence at the nearby Tada Shrine, and the surrounding land became part of his estate. By the Nanboku-cho period, control of the mines had passed to the Otsuki clan, but they could not hold it peacefully. Rival samurai factions -- troops from the provincial governor, the Nose clan, and the Shiokawa clan, who served as retainers of the Tada Shrine -- all fought over access to the veins. When Hideyoshi redeveloped the site during the Tensho era, he shifted operations to the current Inagawa town area, but production remained modest. In 1598, the mine yielded just 476 silver coins, roughly 76 kilograms -- a pittance compared to the Ikuno Silver Mine, which produced 10 tons that same year.

Everything changed in 1660, when miners struck a vein with exceptionally high silver content. The Tokugawa shogunate moved swiftly, seizing direct control in 1661. During the Kanbun era of the 1660s, production peaked at 5.6 tons of silver and 420 tons of copper per year -- numbers that justified the government's interest. But the boom was short-lived. Spring water flooded the deeper workings, making extraction increasingly difficult and expensive. Output dropped steadily, and by 1840 the shogunate had handed the mine off to Takatsuki Domain. Small-scale village mining, the kind that had existed since the Nara period, sputtered along through the end of the Edo period. The magistrate's office that had governed the mining villages was abolished in 1869, closing a chapter of feudal administration.

Mitsubishi purchased the mine in 1895, bringing modern extraction methods to tunnels that had been worked with hand tools for centuries. For a dozen years, industrial-scale mining hummed through the Hokusetsu mountains. Then the global market intervened. A sudden collapse in silver and copper prices beginning in autumn 1907 made operations uneconomical, and the mine closed in 1908. Wartime demand brought one last revival: Japan Mining reopened the workings in 1944, extracting chalcopyrite, bornite, galena, and molybdenite from the hydrothermal veins. But this final chapter was brief. The mine closed for good in 1973. In 2007, a museum opened to preserve the district's long and layered history, and in 2015, the entire complex was designated a National Historic Site -- recognition that a mine can be as historically significant as any castle or temple.