Silver mining in the Friesach region has a long history. In 975 CE, Emperor Otto II granted Imma, the grandmother of Saint Hemma, the right to mint coins in Lieding, along with other privileges. By the 10th century CE, it is certain that silver mining was being carried out near Friesach. These mines proved highly productive, forming the foundation for coin minting. The Archbishops of Salzburg began minting the famous Friesacher penny in Friesach around 1125/30 CE. Although silver mining declined during the 14th and 15th centuries, it saw a revival in the 16th century.

Mining entrepreneurs now came not only from the clergy but also from noble and bourgeois families, who engaged in this profitable business. The Friesach entrepreneur Georg Khanneisen is even referred to as the “inventor of mining” in 1557 CE. The silver ores were processed in two smelting furnaces in Olsa.

Iron mining began around the middle of the 15th century CE. In 1497 CE, a processing plant with a blast furnace and hammer mill was established in Olsa. The Bishops of Gurk gradually acquired all the ore mines and ironworking facilities in the area around Friesach, with the exception of Olsa. These mining operations remained the main source of income for the diocese until the second half of the 19th century CE. The current blast furnace in Olsa was renovated in 1799 CE, but due to the economic crisis, the blast furnace operation had to be shut down in 1876 CE, marking the end of 900 years of mining activity in Friesach.