The Electrical Resistivity of Some Sulphide and Oxide Minerals and Their Ores*

Abstract

The electrical resistivity of 60 pyrite, 31 chalcopyrite, 42 pyrrhotite, 8 arsenopyrite and liillingite, 6 cobaltite, 15 galena, 13 zincblende, 26 haematite, 46 magnetite, 16various manganese minerals, 23 complex ores and 7 graphitic shale samples (mostly from Swedish localities) was measured by the four point method. The method and the precautions needed in its application are briefly discussed. The results are presented in the form of a table which also gives other relevant data on the samples (e.g. percentage of ore in a given sample). The results are believed to be of interest to geophysicists engaged in prospecting for ore by electrical methods.The following can be mentioned among the main conclusions. The electrical resistivity of ore samples varies "locally" on a single sample often by factors of 10-100 but usually within about f 30% and it often varies by much greater amounts (factors of IOO-10000) from one sample to another. The possible causes of such variation are mentioned. The resistivity of pyrite, haematite and magnetite ore samples does not show any significant correlation with the ore content for the samples investigated. There is furthermore no correlation between the standard deviation of the..resistivity on a single sample on the one hand and sample resistivity or ore content on the other hand. In the case of chalcopyrite and pyrrhotite the observations suggested the following relations : For chalcopyrite : log,, (resistivity in ohmcm) = (6.2&4.2)/(vol. y' CuFeS,) -(r.3gfo.38) For pyrrhotite : log,, (rasistivity in ohmcm) = (73 &Ig) / (vol. yO FeS) -(3.26&0.31)The paper concludes by giving the approximate limits within which the electrical resistivity of the various ores investigated appreas to lie. The feasibility of detecting these ores by electrical operations is briefly discussed.

Impedance of black shale from Munsterland 1 borehole: an anomalously good conductor?

“…Such a process would also contribute to lower resistivity in these rocks. However, pyrite, which is also a good conductor with a resistivity as low as 5 X lo-' 52 m (Parasnis 1956), does not contribute to the low resistivity directly because there is no continuous contact between the spheres (Fig. 5).…”

Interpretation of resistivity and magnetic anomalies from the Fox River Sill, Trans Hudson Orogen, Canada

“…Magnetite ore exhibits an extreme range of resistivity with no clear relationship between magnetite content and resistivity. However, results published in Parasnis (1956) are fairly well bracketed by Hashin-Shtrikman bounds for a magnetite resistivity of 0.02 ohm.m and matrix resistivity of 500 ohm.m ( Figure 10). The results suggest that the resistivity of the MZ and serpentinite unit in the LCLZ can indeed be explained the magnetite content provided the magnetite in the LCLZ serpentinite is extremely well-connected.…”

Study of the Resistivity of Coal Seams of the Jharia Coalfield, India

“…Resistivity of different rock types and its dependence on various factors have been studied by several workers, namely Sundberg (1932), Jakosky and Hopper (1937), Archie (1942), Berg (1952), Howel (1954), Parasnis (1956), Sharma and Rao (1962), Sen (1971), Singh et aI. (1972), Barker and Worthington (1973), Singh (1975), and Duba et a1.…”