During 1978, a shallow seismic refraction survey was carried out for Grupo Camargo Correa in the vicinity of Vazante, Estado de Minas Gerais, Brasil. The project achieved the objective of detailed mapping of the subsurface geology of an area covered by residual and transported soils, underlain by deeply weathered, folded and faulted rocks of the Precambrian Bambui Group. Nearly 100 line kilometers of seismic refraction profiling was completed, covering an area of 50 square kilometers. The very irregular bedrock interface and the presence of dipping refractors, required good quality seismic recordings and methods of interpretation suited to complex geologic situations. The operating procedures and methods of interpretation of seismic refraction data, presented in this paper, are applicable to geotechnical investigations for mining and civil engineering projects where great detail of the soil, weathering and bedrock conditions is required.