The prime emphasis of the services provided by PSM is on design supported by appropriate analysis and leading to an ongoing program of monitoring and mapping to check that the design assumptions are borne out by reality. Our fundamental tenet is that accurate engineering geological and hydrological models must be established for any analytical work to be meaningful.

The formulation of an appropriate geological/geotechnical model is critical to underground and open pit rock mechanics studies. Therefore the first phase of any of our studies is to collate available data, both regional and site specific, and to collect additional relevant data by drilling and/or mapping to the stage that we are satisfied the appropriate geotechnical models can be formulated. These models usually comprise plans and cross sections giving an interpretation of the geological and hydrogeological features expected to control rock mass performance and setting out the engineering parameters (strength, deformability, permeability) of the different units and structures. Obviously the level of detail in these models is less for a feasibility study than for detailed design. Final designs are developed using the results of the numerical analyses but within the framework of experience with the performance of similar structures in similar geological environments.

The same philosophy applies to our work in hydrology.

We are very much aware of the fact that, notwithstanding detailed borehole and mapping studies, there remains uncertainty as to the likely performance of the ground. Therefore probability and risk considerations are an important part of our design process and monitoring of actual performance of the structure is crucial to achieving a satisfactory final product. We place great emphasis on having an ongoing partnership for a particular underground or open pit project wherein data (mapping and monitoring) usually collected by the Client is fed back to us for review against the assumptions made for the design.

In summary our approach to geotechnical and hydrologic engineering is:

• site specific data collection programs,
• advanced computer based collation and analysis systems,
• careful integration of rock mechanics data with mine geology to ensure a rigorous geotechnical model,
• use of advanced computer modelling techniques and systems,
• design based on a sound, practicable contruction or mining approach, and
• ongoing mapping and monitoring to check actual performance