Trinh, NQ, Larsen, TE, Molund, S, Nøst, B & Kuhn, A 2019, 'Numerical modelling of the high rock stress challenges at Rana mine, Norway', in W Joughin (ed.), Proceedings of the Ninth International Conference on Deep and High Stress Mining
, The Southern African Institute of Mining and Metallurgy, Johannesburg, pp. 109-122, https://doi.org/10.36487/ACG_rep/1952_09_Trinh
Rana Gruber AS is an iron mining company in the north of Norway, and operates the Kvannevann mine 30 km east of Mo i Rana. The Kvannevann mine is located in a foliated gneiss host rock, with an ore body about 70 m wide and more than 300 m deep. During the history of the mine, it has been in operation for many years using an open-pit mining method, which was later it converted to sublevel-stoping. After thorough planning and preparation, the sub-level cave mining method was put in operation in 2012. Experience from past mining activities and in the preparation of infrastructure for the new mining method indicates that the mine is located in a hard, brittle rock mass with high horizontal stresses. Stress measurements have been made from time to time. The measurement results indicate a major principal stress of approximately 20 MPa perpendicular to the strike of the ore, and a minor principal stress of approximately 10 MPa parallel to the strike of the ore, which is 10–15 times higher than the theoretical vertical stress caused by gravity at the measured location. This paper presents some challenges related to high stress during development and operation of the mine. The paper also presents a comprehensive rock mechanics program, applying a combination of stress measurements, numerical modelling, and monitoring, to deal with the situation.
Rana Gruber AS (2019). History of the company. Website (access on 18/01/2019):
Sand, N.S. (2010). An alternative mining method at the Kvannevann Mine, northern Norway. In Caving 2010 Symposium, Australia: Perth.
Sand, N.S., and Trinh, Q.N. (2011). Rana Gruber rock mechanics challenges connection with the establishment of a new main level and the transition to new mining method. The 45th U.S. Rock Mechanics Symposium. Anthony Iannacchione, Gabriel Esterhuizen, and Azra Tutuncu (eds.). June 2011, San Francisco, USA.
SINTEF. (2011). Project report "Extensometer, 2-D stress measurement, and long-term doorstoppers in Rana Gruber". October 2011, Trondheim, Norway.
Trinh Q.N., Sand N. S., Myrvang A., (2010). Rock excavation and support for a crusher hall at Rana Gruber, Norway. The 44th U.S. Rock Mechanics Symposium and 5th U.S.-Canada Symposium. June 2010, Salt Lake City, USA.
Trinh Q.N., Sand N. S., (2011): Stability study for the footwall at Rana Gruber, Norway. The 45th U.S. Rock Mechanics Symposium. June 2011, San Francisco, USA.
Trinh Q.N., Jonsson Kristina (2013). Design considerations for an underground room in a hard rock subjected to a high horizontal stress field at Rana Gruber, Norway. Tunnelling and Underground Space Technology, Volume 38, September 2013, Pages 205–212.
Trinh Q. N., Holmøy H. K., Larsen T., and Myrvang A., (2016). Continued rock stress and displacement measurements combined with numerical modeling as an active, realistic rock engineering tool. RS2016 Symposium, 7th International Symposium on In-Situ Rock Stress. May 10-12, 2016, Tampere, Finland.