Technical Papers

Caving in the Fabian Orebody —from Mining Stope to Cave Crater in Malmberget

The Fabian orebody is a non-daylighting iron orebody in the LKAB Malmberget Mine in northern Sweden. The orebody was mined using slot caving and sublevel stoping during the 1970s and 1980s, resulting in a large open stope under a 250 m thick crown pillar. The orebody has since been mined using sublevel caving beneath the open stope, which has caused progressive caving and a corresponding continuous reduction of the crown pillar thickness toward the ground surface.

During 2010, a prognosis of the cave development in the Fabian area was developed, based on compilation and analysis of all available material. At this time, the crown pillar had a minimum thickness of 77 m. The prognosis was presented at the end of 2010, and predicted a slow, progressive caving of the crown pillar and the formation of a cave crater on the ground surface within the previously fenced-off area, and with minor disturbance to the surrounding municipality.

The cave development was followed up continuously through laser scanning, visual observations and seismic monitoring. In March 2012, a new cave crater formed on the ground surface above the Fabian orebody, similar to what was predicted. The crater developed in the morning of March 20, with no disturbances to nearby residents or municipal functions.

The prognosis is compared with observations of the caving and the differences and implications quantified. A program for continued monitoring of mining-induced deformation in Malmberget is also described and a criterion for allowable mining-induced surface deformations is proposed.

PRESENTATION

Download the conference presentation.

TECHNICAL PAPER

Sjöberg, J., & Savilahti, T. (2014, January 1). Caving in the Fabian Orebody - from Mining Stope to Cave Crater in Malmberget. International Society for Rock Mechanics and Rock Engineering.

Latest News
  • Thank You to our Summer Interns ITASCA Minneapolis is lucky to have welcomed nine amazing and dedicated summer interns in our...
    Read More
  • Introducing IMAT: Transforming Mining Analysis Solutions Introducing IMAT: Revolutionizing mining analysis with advanced geotechnical modeling and seismic data integration....
    Read More
  • ITASCA Unveils XSite 4.0: Advancing Hydraulic Fracturing Simulation ITASCA announces the launch of XSite 4.0, a groundbreaking advancement in hydraulic fracturing simulation software....
    Read More

Upcoming Events
26 Aug
FLAC3D V9.1 and Griddle V2.0 2024
... Read More
17 Sep
MassMin
Held once every four years, MassMin unites global experts to tackle the industry's most pressing sustainability challenges. MassMin pro... Read More
22 Sep
SMRI Fall 2024
The Solution Mining Research Institute (SMRI) was established in 1965 as a venue for the solution mining and underground storage indust... Read More