Measuring physical properties of the ground — magnetism, conductivity, density — to see structure without drilling.
The use of physical measurements (magnetic, electromagnetic, gravity, or seismic) to detect subsurface geological features and potential mineral deposits. Geophysical surveys are cost-effective exploration tools for identifying drill targets.
Geophysics is how a company decides where to spend drilling money. A well-defined conductor or magnetic anomaly is a target, not a discovery, and the distinction is routinely blurred in press releases.
An anomaly is a physical contrast, and plenty of things that are not orebodies produce one. Until it is drilled it is a reason to drill, nothing more.