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Reassessing Janssen's equation for cave stress estimation in block cave mining
1Norman B. Keevil Institute of Mining Engineering, The University of British Columbia, Vancouver, BC, Canada.
Mining Technology (Abingdon, Eng.)
|May 4, 2026
Summary
Janssen's equation, used for estimating cave stress in mines, may provide inaccurate results due to its limitations. This study reviews the equation's assumptions and highlights differences between silo conditions and fragmented rock in cave mining.
Area of Science:
- Mining Engineering
- Geotechnical Engineering
- Rock Mechanics
Background:
- Deep cave mines face significant draw column heights, necessitating accurate stress estimation for stability.
- Current stress estimation relies on Janssen's equation, derived from silo studies.
Purpose of the Study:
- To review the Method of Differential Slices (MDS) and Janssen's equation assumptions.
- To analyze the limitations of Janssen's equation when applied to cave mining.
Main Methods:
- Review of the Method of Differential Slices (MDS).
- Analysis of Janssen's equation derivation and its underlying assumptions.
- Comparison of silo conditions with cave mining environments.
Main Results:
- Janssen's equation assumptions, based on corn and bulk solids, do not fully represent fragmented rock in cave mining.
- Differences in material behavior (fragmentation) and column conditions (propagation) can lead to stress estimation errors.
Conclusions:
- Janssen's equation is a useful initial tool but has significant limitations for cave mining stress estimation.
- Practitioners must critically evaluate the equation's assumptions and limitations for engineering designs.
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