weather conditions, which probably reduces the frequency and accuracy of the measurements.
There are several manufacturers of total stations (e.g. Leica, Sokkia, Topcon
and Trimble); however, all the open pit Cu–Mo mines in BC use Trimble S8 total stations.
Best practices for pit slope monitoring have been established [11,12], and most
mines treat prism data as being fairly robust and reliable. The highest theoretical precision
that can be achieved for an operating pit environment may be 1-s angle precision
and 1 mm ± 1 ppm distance accuracy. Actual accuracies obtained under field measurement
conditions are less, typically in the range of ±5–10 mm. One advantage of prism
data is that the 3D displacement vector for the prism location is measured, which may
provide insight into incipient failure mechanisms, e.g. toppling versus planar sliding.