exploring the historic iron ore deposits in the Norberg area, in Bergslagen

Exploration license Kallmora nr 1 covers the Kallmorberg ore field in the historic and prospective Bergslagen region, Sweden. Mining in the area dates back to 12th centrury with the Europe’s oldest known blast furnace. During the 18th and 19th centuries, the region was one of the world’s leading iron producers, with bar iron as its main export. Norberg developed into a major mining community, and mining operations there focused on both iron and copper.

The Kallmorberg field has been mined since the 17th century, but organized mining did not begin in earnest until the 19th century. Until then, mining was primarily small-scale copper mining. In the 1870s, Lernbo Grufaktiebolag was formed, which took over the Kallmoragruvan mine and began more systematic mining. Crucial to this expansion was the railroad between Krylbo and Norberg, completed in 1874, which revolutionized the transport of ore and coal. Mining was dominated by iron ore in skarn and quartz-rich ores, while the copper deposits were short-lived and of limited extent.

Geologically, the Kallmorberg field consists mainly of skarn ores, banded iron formation ores, and copper mineralizations. The skarn ores, consisting of calcareous silicate rocks, contain primarily magnetite but also copper minerals such as chalcopyrite. The quartz-banded ores consist of alternating layers of quartz and iron minerals, while the copper deposits occur primarily in the skarn streaks. The field’s geology is characterized by many small but high-quality deposits that are often associated with favorable stratigraphic settings. The complex geology, with its numerous mineralization zones, makes the area attractive for further exploration, as previous mining has primarily taken place in the shallower parts.

Between 1870 and 1978, the Kallmorberg field underwent several phases of expansion and decline. Starting in the 1870s, mining increased significantly thanks to industrialization and more modern methods. A total of approximately 3.28 million metric tons of ore was extracted, of which 650,000 metric tons was lump ore and 780,000 metric tons was tailings. Copper mining was more limited but took place during the 18th century and the early 20th century. During the 1920s, operations were taken over by Surahammars Bruks AB, which introduced a concentrator and bench mining to address the low ore grade. Mining continued until 1976, when it was phased out due to reduced profitability and lower iron content in the ore. The concentrator was closed in 1978.

When mining operations ceased, the remaining ore resources were estimated at approximately 3.56 million metric tons, of which 2.67 million metric tons were classified as proven reserves and 0.89 million metric tons as estimated resources. These resources were primarily located at deeper levels, between 230 and 295 meters, and had never been fully explored.

Today, the Kallmorberg field stands out as a highly promising exploration target. The field has a confirmed historical production record of both iron and copper ore, demonstrating its potential for economically viable deposits. Furthermore, it is estimated to contain significant remaining ore resources of approximately 3.56 million metric tons, making it a substantial asset. The unexplored potential for new deposits, particularly at deeper levels, makes the area even more interesting.

To explore this potential, a systematic survey can be conducted. Geophysics can be used to identify ore zones and skarn belts. Geochemical sampling to the base of till and rocks can provide information on the extent and grade of the mineralization. In addition, diamond drilling can be carried out, particularly at deeper levels and in previously unexplored areas, to confirm the presence and size of any new deposits.

In summary, the Kallmorberg Field presents a highly promising opportunity for further exploration and the potential resumption of mining operations. With the right exploration methods and economic conditions, the area could contribute to a new generation of ore deposits, especially if the focus is on the deeper, previously unexplored parts of the field.