The Benefits of Applying Geophysical Techniques on a Port Geotechnical Investigation in Brazzaville, Congo

In recent years there have been many publications on the advances in geotechnical modelling software and associated techniques, capable of performing high level analyses, however the fundamentals of formulating a comprehensive ground model are still very much contingent upon the information gathered during the data collection campaign. Traditional methods of geotechnical data collection involve invasive methods such as boreholes and test pits, these approaches require the mobilisation of ground engaging equipment, this process can require significant logistical arrangements in terms of access and clearing. Owing to the current economic climate and general uncertainty in commodity prices, a number of clients in the mining sector are therefore having to either defer or compromise the extent of such geotechnical investigations to minimise upfront expenditure to ensure that other aspects of the project development can be adequately funded. This paper describes an overview of the use of non-invasive geophysical techniques to capture detailed geotechnical information to assess ground conditions. The focus is on the application of the multi-channel analysis of surface waves (MASW) technique to a prospective port facility run by Cominco Resources Ltd. (Cominco) in Congo Brazzaville. The remoteness of the site posed a number of logistical constraints which would have rendered boreholes drilling infeasible. The case study successfully demonstrated how the overall process was implemented and the time and cost savings that were achieved by optimising the port site geotechnical investigation campaign by significantly reducing the requirement for invasive investigations.