Electrical methods case studies

Pine point mineralization, Northwest Territories

Strata-bound sulphide deposit (lead-zinc-silver in a limestone host rock)

Background effects in limestone are very low

Resistivity pseudo-section relatively featureless

FE and MFE sections show persistent anomaly, even at very large spacing.

Detection of clay lens in an aquiferMap of PFE detects a clay-rich lens in a sandy gravel

Clay reduces the fluid permeability

Hence the IP survey aided in the assessment of the potential of the aquifer as a reservoir

Disseminated porphyry copper

Relatively featureless resistivity, discovery of mineralization made on the basis of the MF pseudo-section.

Discovery is ore-grade, in spite of low grade due to copper and molybdenum.

Disseminated sulphide

Deeper deposits inferred from psuedo-section: note large spacing required to detect MF anomaly

Gortdrum copper-silver, IrelandLimited data (one profile only, no pseudo-section)

Chargeability anomaly well defined, centered over ore body.

Lornex copper porphyry, British Columbia

Resistivity shows only a mild increase to the east – probably due to thinning of conductive overburden

Short spacing IP shows the mineralization, relatively low grade at the east.

Long spacing IP indicates mineralization continues at depth to the west.

Krain sulfide deposit, British Columbia

Model study of “inversion”

Psuedo section Inversion result, or “real” section

Model study of “inversion”

Psuedo section Inversion result, or “real” section

Example of “inversion”, Century deposit, Australia

Pseudo-section

Inversion result, with interpretation

Predicted IP data

Dam leakage, Mexico