464 



EXPLORATION GEOPHYSICS 

 FIELD RESULTS 



A number of equipotential surveys for the location of ore have been 

 described by Lundberg t and by Broughton Edge and Laby. t The sur- 



LEGEND 



— — INDICATION UNDETAILED 

 Y— INDICATION CONTINUES 

 — ^ INDICATION STOPS 

 1 RESISTIVITY PARALLEL 



o DRILL hole: 



—<:;.- CREEK OR eULCH 

 — — AREA SURVEYED 



• p 



Fig. 277. — Results obtained in an alternating current equipotential line survey in 

 Pinal County, Arizona. 



veys of the latter investigators (with one exception) were made in the 

 eastern part of Australia (Queensland, New South Wales, Victoria and 

 Tasmania). 



Figure 277 shows the results obtained in an alternating-current equi- 



t Hans Lundberg, "Recent Results in Electrical Prospecting for Ore," A.I.M.E. Geophysical 

 Prospecting, 1929, p. 105, p. 110, pp. 120-122. 



t A. Broughton Edge and Laby, loc. cit., pp. 74, 83, 86, 92-94, 111, 116, 122. 



