High levels of critical raw materials such as rare earth elements, phosphorus and tungsten are found in old mining waste in Bergslagen. This is shown by two new reports from the Geological Survey of Sweden (SGU). The potential resources are far from sufficient to meet the needs of Europe’s industries but could still contribute to the supply of critical raw materials.
The need for critical metals and minerals for the ongoing energy transition is great, while production in both Sweden and the EU is very small. As part of a government directive from 2021, the Geological Survey of Sweden (SGU) has therefore investigated the possibilities for extraction of critical metals from mining waste, such as waste rock and tailings.
SGU has released the results from sampling of mines in central, western, eastern, and southern Bergslagen, which show that there are significant levels of critical and strategic raw materials in the mining waste there.
Mining waste from Bergslagen could supplement the primary production of critical metals and minerals. Such extraction would also provide opportunities for remediation of former mining sites, says Patrick Casey, geologist at SGU.
High levels of critical metals in the waste are not enough, however. There also need to be large amounts of mining waste for extraction to be economically viable. Therefore, the new reports also present estimates of remaining amounts of metals and minerals in both waste rock and tailings.
Grängesberg, for example, was one of the largest mines in the western Bergslagen and iron ore has been mined there since the 18th century. The tailings reservoir that belonged to the mine is estimated to contain 21,500 tons of rare earth elements, 156,000 tons of phosphorus and 2.2 million tons of iron.
The estimates presented in the reports are nowhere near the amounts needed for industry in Europe but could be a significant addition. Also, the estimates do not consider what is possible to extract.
Considering the tailings, new geophysical field measurements and density determinations have formed the basis of the calculations. For the waste rock estimates, on the other hand, the production numbers are taken from historical data, which has made it difficult to calculate the potential amount of critical raw materials, says Gunnar Rauséus, geologist at SGU.
The production figures for the waste rock can be misleading, as material may have been moved from the site and, for example, used as backfill or ballast. Therefore, new resource estimates would be needed, which also include detailed surveys of remaining waste rock. Such calculations were not a part of SGU’s assignment.
Source: SGU
