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
  • Now Available from ITASCA: Innovative Machine Learning Tool for FLAC3D/FLAC2D V9.2 Experience the Future of Geotechnical Modeling with ITASCA Software V9.2: Introducing Machine Learning Models...
    Read More
  • Experience the Future of Geotechnical Modeling with ITASCA Software V9.2 Experience the Future of Geotechnical Modeling with ITASCA Software V9.2: Introducing Machine Learning Models and...
    Read More
  • Thank You to our Summer Interns ITASCA Minneapolis is lucky to have welcomed nine amazing and dedicated summer interns in our...
    Read More

Upcoming Events
29 Oct
Getting Started with 3DEC
Objectives of the training: Understand the 3DEC numerical approach and the types of problems it can solveKnow how to manipulate the 3DE... Read More
27 Oct
Geothermal Rising
The Geothermal Rising Conference is the geothermal industry’s flagship annual conference, reflecting the global nature of the geotherma... Read More
5 Nov
Python in Itasca Software
This course provides an overview of the Python programming language in Itasca software.The course covers major applications of Python t... Read More