Dannemora Mining Geotechnical Feasibility Study

Challenge

Grangex required feasibility level data collection, updating of the geotechnical characterisation, and subsequent confirmatory geotechnical analysis of the geotechnical underground stoping design for the restart of the Dannemora Iron Ore Mine.

Solution

SLR were selected for this project as we have sound understanding of the project ground conditions and technical aspects, world-wide experience in carrying out geotechnical data analyses programs and extensive underground mine design and operations experience. The following pieces of work were undertaken:

• Stope stability design
• Stope ground support design
• Estimate of unplanned stope dilution
• Pillar width design
• 3D numerical stress modelling

Impact

SLR conducted geotechnical analyses in support of mining the Dannemora orebodies using available site characterisation data. Using data supplied by the client and that sourced by SLR as part of this study, a geotechnical model composed of the following inputs was analysed; geological, rock mass, structural, hydrogeological, and geotechnical domains.

The analyses showed that the planned stopes are generally stable, though SLR provided recommendations for alterations to the mine design and schedule where potential stabilities issues were identified to potentially occur.

The ground support classes were tailored for the rock conditions alongside specific ground support provided for stope brows, large excavations, and intersections.

"Grangex AB (Grangex) engaged SLR Consulting to assist in the restart of the Dannemora Iron Ore Project, Sweden. The project was a complex undertaking, requiring a deep understanding of the challenges and opportunities facing the mining industry. The now environmentally-permitted Dannemora Project is designed to ensure that the extraction of iron ore is maximised through the use of Green Technology with a carbon free focus. SLR Consulting's expertise in all aspects of mining, from exploration to operations and closure, was essential to the project's success. In addition to their technical expertise, SLR Consulting also has a highly personable, skilled team, with regional expertise; which are aspects invaluable to Grangex, aligning with our approach to working.

SLR Consulting also has a proven track record in delivering projects on time and on budget, facilitated by sound and practical project management. This was evident for the Dannemora Project, which led Grangex to expand our relationship with SLR in our ongoing work in Norway.

We look forward to working with SLR on future projects."