Hoek, E., Hutchinson, D.J., Kalenchuk, K.S. and Diederichs, M. 2009. Influence of in situ stresses on open pit design, Appendix 3 in Guidelines for Open Pit Design, (eds. J. Read & P.F. Stacey). CSIRO Publishing, Melbourne: 437 – 445.
All rock masses are subjected to in situ stresses resulting from the weight of the overlying strata and from locked in stresses of tectonic origin. The excavation of an open pit results in disruption of the existing stress field with some of the stresses being relieved, while others are intensified. These changes in the in situ stresses can have very important consequences in terms of the behaviour of the rock mass surrounding underground excavations. However, the question to be considered in this appendix is whether these stress changes are important in the design of the slopes of an open pit mine.