Mine pit slopes in the Pacific
Rim are a geotechnical challenge because of the complex geology in
which they are developed. Mines are currently being fast-tracked to meet the
increase in commodity prices, often resulting in some reduction in ground
studies and short-cutting of design procedures. In addition, the resources boom
means that skilled personnel are in relatively short supply. At a time when mine
pits are getting bigger and deeper, and the engineering is getting more
demanding, there is an increased demand on managers to effectively implement the
work.

Experience both in New
Zealand and the Philippines, display the complex
range of geological environments in which pits are being excavated. Working in
these conditions has shown that successful geotechnical design requires a strong
geotechnical model based on sound geology. An appropriate level of investigation
and analyses results in a certain level of understanding for the mine design.
There is a point where additional expenditure (on investigation and analyses) is
not warranted based on the expected minimal impact on decreasing the level of
perceived risk on the project. For most
projects in our experience the analytical methods and complexity of geotechnical
assessment changes increases as the level of knowledge
grows.