KEY BENEFITS

SIL has extensive experience in applying state of the art non-invasive ground characterization techniques to all areas of geotechnical, civil engineering, mineral and gem, groundwater and industries

Ground Penetrating Radar System
(GSSI SIR - 3000) with Multiple
Antenna (400 MHz, 100 MHz Bistatic
and Multiple Low - frequency).

Ground Penetrating Radar (GPR) utilizes pulsed high frequency radio waves to probe the subsurface without disturbing the ground. The GPR data are collected continuously as the instrument is towed over the ground surface and provides a real-time graphic image of the subsurface.

Data can be processed and presented as individual radagrams. These are essentially two dimensional cross sections of the subsurface. Modern software now enables stacking of adjacent radargrams and the construction of three – dimensional data cubes. Horizontal slices (or “time slices”) through the data at the desired depth enables visualization of the reflection strength across the area.

 GROUND PENETRATING RADAR PROFILE SHOWING
LIKELY DETECTION OF GEOLOGICAL
      INTERFACES AND HETEROGENEITY IN WEATHERING ( USING 20MHZ ANTENNA)

Geometric StrataVisor NZXP 24 -
Channel System

Seismic Refraction is a useful method for investigating geological structure and rock properties. The technique involves the observation of a seismic signal that has been refracted between layers of contrasting seismic velocity. Shots are deployed using a hammer/gun/explosive source at the surface and shockwave data recorded via a linear array of geophone sensors. The travel-times of refracted signal are derived from the data and are then processed to determine depth profiles of the targeted geological boundary.

Seismic Surface Waves Measurement: With a growing need for rapid, non-destructive geologic site characterization comes more efficient and cost effective seismic methods that allow for more complete site coverage in less time. Seismic shear-wave velocity is a key parameter for determining the elastic properties of soil and rock for geotechnical investigation. In-situ measurements of shear-wave velocity are traditionally made with seismic cross-hole methods or through non-invasive methods such as Spectral Analysis of Surface Wave (SASW). A relatively new improvement to SASW known as Multi-channel Analysis of Surface Wave (MASW) allow shear-wave measurements to be made at multiple locations in a more efficient and cost effective manner.

 Surface wave velocity profile showing the advantage of carrying out seismic
survey to map rockhead between exploratory boreholes

AGI Advanced Geoscience Inc.
SuperSting R8/IP8 - channel Memory
Earth Resistivity and Induced
Polarization system.

Cave detection using resistivity
imaging technique

Electrical Resistivity Imaging: Electrical properties are among the most useful geophysical parameter in characterizing Earth materials. Variations in electrical resistivity typically correlate with variations in lithology, water saturation, fluid conductivity, porosity and permeability. Electrical Techniques (Resistivity Imaging) seek to describe the distribution of these properties as a function of depth and horizontal distances. Resistivity data are recorded via complex combinations of current and potential electrode pair to built up a pseudosection of apparent resistivity beneath the survey line. The modeled true subsurface resistivity image is then derived from finite-difference forward modeling via specialist software.

In nature, the induced polarization (IP) effect is seen primarily with metallic sulphides, graphite, and clays. For this reason, IP surveys have been used extensively in mineral exploration. Recently, IP has been applied to hazardous waste landfill and groundwater investigations to identify clay zone. The time domain IP technique energizes the ground surface with an alternating square wave pulse via a pair of current electrodes. On most surveys, the IP/Resisctivty measurements are made on a regular grid of stations along survey line.

Mineral Exploration using the Resistivity / IP imaging technique.