Comparison of crosshole radio imaging and electrical resistivity tomography for mapping out disseminated sulphide mineralisation at a surface test site in Mpumalanga, South Africa

1999 ◽  
Vol 30 (3-4) ◽  
pp. 135-139 ◽  
Author(s):  
Michael van Schoor ◽  
James Duvenhage
Keyword(s):  
South Africa ◽  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
Test Site ◽  
Resistivity Tomography ◽  
Radio Imaging ◽  
Sulphide Mineralisation ◽  
Surface Test

scholarly journals Assessment of the Efficiency of Consolidation Treatment through Injections of Expanding Resins by Geotechnical Tests and 3D Electrical Resistivity Tomography

2015 ◽  
Vol 2015 ◽  
pp. 1-13 ◽  
Author(s):  
T. Apuani ◽  
G. P. Giani ◽  
M. d’Attoli ◽  
F. Fischanger ◽  
G. Morelli ◽  
...  
Keyword(s):  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
Three Dimensional ◽  
Test Site ◽  
Mechanical Stiffness ◽  
Foundation Soil ◽  
Resistivity Tomography ◽  
Consolidation Treatment ◽  
Injection Process ◽  
Geotechnical Tests

The design and execution of consolidation treatment of settled foundations by means of injection of polyurethane expanding resins require a proper investigation of the state of the foundation soil, in order to better identify anomalies responsible for the instability. To monitor the injection process, a procedure has been developed, which involves, in combination with traditional geotechnical tests, the application of a noninvasive, geophysical technique based on the electrical resistivity, which is strongly sensitive to presence of water or voids. Three-dimensional electrical resistivity tomography is a useful tool to produce effective 3D images of the foundation soils before, during, and after the injections. The achieved information allows designing the consolidation scheme and monitoring its effects on the treated volumes in real time. To better understand the complex processes induced by the treatment and to learn how variations of resistivity accompany increase of stiffness, an experiment was carried out in a full-scale test site. Injections of polyurethane expanding resin were performed as in real worksite conditions. Results confirm that the experimented approach by means of 3D resistivity imaging allows a reliable procedure of consolidation, and geotechnical tests demonstrate the increase of mechanical stiffness.

scholarly journals Using Electrical Resistivity Tomography (ERT) to Delineate Subsurface Structures at Siloam Hot Spring in the Soutpansberg Basin, South Africa

2018 ◽  
Vol 10 (4) ◽  
pp. 19
Author(s):  
Peter K. Nyabeze ◽  
Oswald Gwavava ◽  
Matome Sekiba
Keyword(s):  
South Africa ◽  
Electrical Resistivity ◽  
Electrical Resistivity Tomography ◽  
Hot Spring ◽  
Spring Water ◽  
High Resistivity ◽  
Resistivity Tomography ◽  
Subsurface Structures ◽  
Rho A ◽  
Schlumberger Array

Electrical resistivity tomography (ERT) was used to delineate subsurface structures at Siloam hot spring in the Soutpansberg Basin of South Africa. The spring water was reported to be hottest in South Africa. Groundwater with temperature ranging between 63.3 °C and 67.5°C was observed flowing from the spring. Relatively wet areas were noted to the south and north of the spring. Electrical resistivity arrays with Dipole-dipole and Wenner-Schlumberger configurations were used. Current injection and potential dipole separations of 5 m and 10 m were applied across the spring. Inversion results for arrays with the shorter dipole separation of 5 m had better resolution. Resistivity sections were generated from inversion of ERT data. The resistivity values for the low and high resistive zones were ρa < 10 and ρa > 70 Ωm respectively. Sub-horizontal resistivity zones were obtained from the inversion of Wenner-Schlumberger array survey data. High resistivity zones associated with dykes or sills were delineated on Dipole-dipole derived depth sections. Near vertical structures associated with water bearing faults or fractures were delineated at the Siloam hot spring.

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