Abstract
D.Ing. (Civil Engineering)
This thesis describes an Investigation Into the nature of the
fracture and deformation mechanism which occur at the edges of
tabular gold mining excavation. Published Information on these
phenomena Is reviewed, and the necessary underground Investigation
required to consolidate the previous work Is described. It Is
concluded that the rock near the reef plane at the edges of these
mining excavations Is subject to stresses sufficiently high to
cause It to fracture through the formation of regular patterns of
shear planes. These fractures can form In the solid rock some
distance ahead of the mining excavation. Nearer the mining face,
extension fractures form which result In slabbing or splitting of
the exposed rock.
An Idealization of the observed rock behavior Is proposed, which
Is then incorporated with conventional boundary element techniques
Into a numerical model (SEAMS) which Is capable of analyzing two Dimensional
tabular mining excavations where the rock near the
reef plane at the edge of the mining excavation fractures, deforms
and sheds load. A Sensitivity analysis of the numerical model Is described which
Identifies those mining parameters capable of being used to
advantage In controlling the size of the fracture zone.