Catastrophic Collapse of Highwall Web Pillars and Preventative Design Measures


In highwall mining, once a sufficient number of web pillars are developed, they can fail catastrophically in a domino-type failure, posing a safety hazard to highwall miners and sterilizing mineable reserves. Three recent case histories of catastrophic web pillar failure in U.S. and Australian mines are documented and analyzed with two design approaches. The conventional design approach uses only a strength criterion, while the postfailure design approach uses both strength and stability criteria to insure an acceptable failure mode should strength failure occur. Catastrophic highwall web pillar failures can cost money through equipment losses, production losses, coal reserve sterilization and lost opportunity costs. Coal recovery may be higher. but the benefits of higher recovery must balance the potential costs of failure. Application of the conventional or postfailure design approach will decrease coal recovery and revenues, but the risk of potentially costly failure is much less.

Meeting Name

18th International Conference on Ground Control in Mining


Mining Engineering

Document Type

Article - Conference proceedings

Document Version


File Type





© 1999 Society for Mining, Metallurgy & Exploration Inc. (SME), All rights reserved.

Publication Date

01 Jan 1999

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