LKAB is one of the largest underground Iron mines in the world and definitely the largest in Europe. LKAB operation is situated in Norrbotten County – north of Sweden. There are two underground mines Kiirunavaara mine in city Kiruna and Malmberget mine next to Gällivare town. With very different ground conditions and rock formations, both mines are exposed to dynamic events. Kiruna mine geology consist of several Karelian and Svecofennian metavolcanics and metasediments. These rocks might have originally been basalt, trachyandesite, rhyodacite, and rhyolite altered by metasomatism. These rock formations are very compact and hard, with a lot of accumulated stress causing issues with rock bursts. Malmberget’s ores are hosted in Precambrian volcanic rocks that have largely been metamorphosed to gneisses. Containing apatite-bearing iron ore, the entire deposit complex has been strongly folded and now consists of a number of ore sheets that may have originally been connected. That type of rock formation is highly deformable under stress, causing large convergences.
Due to challenging geological conditions in both mines and high demand on safety and productivity, LKAB was looking for rock bolts with high static and dynamic capacity. Bolts with high impact resistance to cope with rock burst, yet strong and ductile to absorb and suspend energy in swelling and yielding ground.
For many years, Normet has supplied the D-bolt® for individual projects within the LKAB development. Performance of the D-bolt®, which was used during Kiirunavaara mine KUJ 1365 project (development of new production level) and during repairs of roof falls in Malmberget mine was setting second to none. The D-bolt® had an excellent reputation as a dynamic bolt within LKAB operations. For several years, the D-bolt® was used in LKAB for special applications. In 2019 after other suppliers failed to supply bolts of high-performance parameters, Normet was invited by LKAB to participate at tender for the full LKAB bolting needs. Normet presented an unbeatable offer, superb bolt performance and reliable supply. In addition, our new local manufacturing production facility in Lulea offered “Steel back to the Mine” concept, local support and exceptional service. All these points were the driving forces to success! Between April 2019 and March 2020, Normet delivered over 400,000 bolts to LKAB. During the full year of supply, we had no technical issues and never missed a delivery, proving Normet to be leading and reliable supplier and respectful business partner.
D-Bolt 20 x 3000mm with Kiruna wedge