Geological mapping is the systematic field-based observation and recording of geological information—including rock types, stratigraphic relationships, structural features, alteration zones, mineralization occurrences, geomorphological features, and regolith characteristics—across a defined geographic area, resulting in the production of geological maps, sections, logs, and associated databases. Geological mapping is one of the most fundamental tools in mineral exploration and mining geology, providing the spatial framework for all subsequent exploration and resource evaluation activities across bauxite, gold, iron ore, and diamond mining.
Surface geological mapping involves the direct observation, measurement, and recording of geological features in the field, typically at scales ranging from 1:100,000 for regional reconnaissance to 1:1,000 or larger for detailed pit mapping in operating mines. Field data are recorded on base maps, field notebooks, digital tablets, or mapping apps such as Fulcrum, QGIS, or SeequentCentral, with GPS coordinates enabling accurate spatial referencing of observations. Structural data (strike, dip, plunge, lineation) are measured using geological compasses and clinometers, with data analyzed using stereonet plots to identify dominant structural orientations and kinematic indicators.
In gold mining, systematic geological mapping of open pit faces and benches is an ongoing operational activity providing real-time geological data for grade control purposes. Face maps record lithological contacts, alteration zones, vein networks, fault traces, and structural orientations at scales of 1:200 to 1:500, providing the geological context for interpreting blast hole assay data and guiding ore/waste discrimination decisions.
In bauxite mining, surface mapping characterizes the distribution and quality of surface laterite exposures, maps the extent of ferricrete hardcap, and identifies geomorphological features indicative of bauxite-favorable plateau remnants. Regolith mapping, often supported by remote sensing and airborne geophysical data, guides auger drilling program design to systematically sample the full extent of prospective laterite terrain.
In iron ore exploration, geological mapping of BIF exposures characterizes the stratigraphic column, identifies fold and fault structures controlling ore zone geometry, and records the distribution of surface gossans and iron oxide staining that may indicate zones of supergene enrichment.
Underground geological mapping in gold and diamond mines records face, back, and rib geology in development drives and stopes, providing continuously updated geological models that guide blasting pattern design, grade control sampling, and ground support installation decisions.