The Use of Multiple Geophysical Techniques to Detect Structural - PowerPoint PPT Presentation

BBUGS & BOHOGS 2015 Supplier and Consultant Day The Use of Multiple Geophysical Techniques to Detect Structural Features Author: Wes Nichols Co-Author: Warwick Smyth

Mine-Scale Case Study – Fault • TSIM – Shallow layer VLF-EM technique (down to 50m) – Uses VLF transmissions (e.g. 19.8kHz @ NW Cape) – Resistivity contrast • Borehole Acoustic Scanner – Measures acoustic impedance of borehole wall – Defect/bedding/structure identification • RIM – In-seam borehole-borehole radio imaging – Used for confirmation only

Fault Detection • Near-surface expression

TSIM Grid (100m x 150m – 10m)

Holes targeted to TSIM Results

Downhole Acoustic Scanner Example: Chip hole R1833

Level of fault

RIM: In-seam EM (Borehole-Borehole) Direction of highwall advance

Geotechnical Implication Wedge failure risk

Interpretation of Structural Regime

3D Schematic Interpration

Top of Coal Surface Showing Interpreted Faults

Mine-Scale Case Study - LOX • TSIM – Shallow layer VLF-EM technique (down to 50m) – Uses VLF transmissions (e.g. 19.8kHz @ NW Cape) – Resistivity contrast • Confirmed by drilling

LOX Definition

Mine-Scale Case Study – Alluvium/Surface Channel Deposits • TSIM – Shallow layer VLF-EM technique (down to 50m) – Uses VLF transmissions (e.g. 19.8kHz @ NW Cape) – Resistivity contrast • Confirmed by drilling

Alluvial Thickness Mapping

TSIM – Structural Targets • Near surface expression of geological structures of Geotechnical Importance • Target types outlined in this presentation – Faults (TSIM + Scanner + RIM) – LOX/subcrop (TSIM) – Alluvium (TSIM)

TSIM VLF-EM • Provider to industry • $100,000+ in R&D expenditure • Development of new TranSIM instrument in progress • Handleability and ease of operation • Cost advantage • Saving in Drilling Costs

Scanner Interpretation Services • Defect mapping • Stress regimes • Full interpretive report

Questions?