The force-field methods, magnetic, electrical resistivity and equipotential, self-potential, electromagnetic,gravimetric and geothermal, where the forces observed result from the action of natural or artificial fields areall limited by the decrease in anomaly according to an inverse power law with the depth of the anomalous body. Furthermore large physical-property contrasts frequently occur in the surface material, making the detection andinterpretation of subsurface conditions difficult. The mining structures controlling ore deposition are small, measuring the order of feet to hundreds of feet, and are manifold in number. The direct detection of ore is seldom possible. A more accurate assessing of the limitations and scope of existing methods to know the extent of their application, more rigorous mathematical interpretation procedures, development of methods for the detection of scattered sulphides, and drill-hole and underground exploration techniques are suggested as worthy of study.