Borehole IP / Resistivity
Applications in Mineral Exploration
- Identifying gold-bearing veins with sulphides.
- Mapping disseminated sulphides and stringers surrounding VMS.
- Discriminating between barren and mineralized EM conductors.
- Identifying sphalerite, discontinuous banded mineralization, non-conductive sulphides.
- Mapping of alteration zone and structural features controlling mineral deposit? (Porphyry cooper system).
- Mapping of clay minerals and/or magnetite associated with kimberlitic rocks.
- Resistivity mapping for alteration, basin depth.
- Selecting the best electrode array for reconnaissance, depth penetration or detail target mapping.
Equipement and Software
| Transmitter | Tx-III from GDD Instruments (up to 7,8 Kw) |
| Receiver | Elrec-Pro from IRIS Instruments (10 input channels and 20 decay curve sampling windows) |
| Borehole cable | Custom manufactured shielded cable for BHIP, pole-dipole, a = 20 m, n = 1 to 6 |
| In-field QC | Processing and plotting are performed using our proprietary Refusilo® software. |
| Analysis | Image2D, Image3D, Res2Dinv, Res3Dinv, UBC 3D |
Borehole IP Configuration and Survey Parameters
| BOREHOLE Survey Features | H2H-3D-IP® | Down-hole, Pole-dipole |
|---|---|---|
| Radius of investigation | may exceed 400 m | generally < 120 m |
| Depth of investigation | 3,000 m | 2,000 m |
| Radius of investigation proportional to borehole spacing | X | |
| Radius of investigation proportional to electrode spacing in hole | X | |
| Explore below the borehole | X | |
| Investigation is not affected by conductive overburden | X | X |
| Each additional hole-pair improves the delineation of the source geometry | X | |
| Detect disseminated sulphides between holes | X | X |
| Survey cost less than 5% of drilling cost | X | X |
| Inexpensive probe and cable is used | X | |
|
H2H 3D IP® electrode Configuration The radius of exploration "r" is half the distance between the hole-pairs being surveyed and extends below the bottom of the hole. |
Classical Borehole IP electrode configuration The radius of exploration is limited by the electrode spacing, which in turn is limited by the hole length. Abitibi Geophysics uses a specially engineered cable to avoid capacitive coupling and to enable recording of 6 dipoles simultaneously. This configuration with short electrode separations is particularly useful for collecting a physical property mapping. |
Supplied Products - Borehole IP
- Image3D® images showing the location of all resistive, conductive and polarizable features within the array’s investigation radius.
- 3D reconstructed chargeability and resistivity database.
- Colour plan views and cross-sections of the recovered resistivity and chargeability.
- 3D videos of the resistivity and chargeability main features.
The following is from a H2H-3D-IP®inversion presented as a 3-D animation of the 25 mV/V (yellow) and 40 mV/V (green) chargeability iso-surfaces. The inversion shows the chargeability source (disseminated sulphides) as a target shape accurately positioned using the client’s borehole coordinate system.
Visit our Case Study Tool to see what Borehole IP has discovered over the years.
– deep TDEM
- Deep TEM