A geotechnical investigation is a structured program of field exploration, sampling, testing, and analysis undertaken to characterize the physical and mechanical properties of subsurface materials — soils, rocks, and groundwater — to support engineering design and risk management in mining projects. In bauxite, gold, iron ore, and diamond mining, geotechnical investigations are conducted at various scales and levels of detail depending on the project stage, from regional reconnaissance investigations during early exploration to detailed site-specific campaigns at feasibility and construction stages. The scope of a geotechnical investigation typically includes desk studies of existing geological and geotechnical data, field mapping of rock mass exposures, geotechnical borehole drilling programs, installation of monitoring instrumentation, in-situ testing, and laboratory testing on retrieved samples. Laboratory testing programs for geotechnical investigations include uniaxial compressive strength (UCS) testing, triaxial shear strength testing, point load index testing, Brazilian tensile strength testing, and consolidation testing for soils. Hydrogeological characterization — including pump tests, slug tests, and packer testing — forms a critical component of geotechnical investigations for mines where groundwater pore pressures drive slope instability. For underground mines in iron ore (such as sublevel cave or block cave operations), geotechnical investigations must characterize rock stress environments through hydrofracture or overcoring measurements. Diamond mines in kimberlite require dedicated geotechnical investigations to address the jointing patterns, alteration zones, and contact relationships between kimberlite facies and surrounding country rock.
