Abstract: İt is well known that the existence of slag heaps ,and galleries containingacid waters, near sulphide deposits, make It extremely difficult, If not impossible, to Interpret the self potential measurements taken around them.This is due to the generation of self potentials by the slags ,and wet galleries,having magnitudes of the same order as those given by the deposit itself.Hence, the elimination of such effects from the total anomaly is essentialfor an intelligible interpretation of the total anomaly.

The problem of elimination of these effects is attacked in two ways:

1. By the method of finite differences with the resulting linear equations solved by relaxation methods.

2. By an empirical method of finding the self potential moment of theslag / gallery ,and thereby proceeding to the calculation of the spuriouseffect.