(a) Geological surveys are surveys of the geology of mineral deposits. These are done by, among other things, taking mineral samples, mapping rock units, mapping structures, and mapping mineralized zones.
(b) Geochemical surveys are surveys of the chemistry of mineral deposits. They are done by, among other things, sampling soils, waters, and bedrock to identify areas of anomalous mineral values and quantities that may in turn identify mineral deposits.
(c) Geophysical surveys are surveys of the physical characteristics of mineral deposits to measure physical differences between rock types or physical discontinuities in geological formations. These surveys include, among other things, magnetic and electromagnetic surveys, gravity surveys, seismic surveys, and multispectral surveys.