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Gold
Research Locality.
The middle part of gold-bearing region Big Nugget Hill located to north-west direction by
many dozens of kilometers with width from 50 to 300 meters. Ore zone consists of quartz cager
vein in the central part which on flanks passes to region on small veins and strings of the
same composition. Transition sones are gradual. Ore zone alterations are represented by
argillization (clay grouting) with iron. Bearing strata are carbonaceous slates with
thin-layer sulphides. Ore formation - gold-quartz. Objectives:
Boundary tracking of above mentioned ore zone to the depth on testing area.
Evaluation of the possibility of georadar surveying for finding and tracking of
steeply-falling contrasting media in conditions of greatly wet bearing strata.
Figure 1 shows radarogram obtained during passing of profile across ore zone by georadar
GROT-11 with 4 meters antennas which allow to cross ore body by full visible thickness.
Figure 2 shows radarogramm obtained during passing of profile across ore zone by georadar
GROT-10 with 1.5 meters antennas.
In result of carried out subsurface sounding on the site the following anomalous objects
have been discovered: tectonic disturbances, ironing zones, quartz veins including
neighboring areas of breakage and argillization. Ore zone consists of quartz vein with
changes in neighboring areas. On radarograms it is displayed as a series of hyperbols, their
top points can be iterpretated as centerlines of probable vein and neighboring areas of
breakage.
Opals
Field work was carried out by the method of profile-georadar-surveing on four testing and six
investigation areas located in various districts of the Lighting Ridge bearing region.
The use of profile-georadar-surveing made it possible in real-life conditions to locate and
track to depth main and secondary dislocations with a break of continuity, thereby allowing
one to establish spatial location of potential local bearing zones and to determine the depth
of the most contrasting reflecting horizons corresponding to contact points of composition
area heterogeneous rock types. The borders of separation between siliceous conglomerates and
lower-lying dense white sandstones (2-4 m) stand out most clearly; as do those sandstones
kaolinised to varying degrees with low-laying clays (10-12; 17-24 m) and boundaries of
horizons of varying degrees of water saturation.
Georadar GROT indicated the exact position of opals in the ground.
Figure 1 shows the typical cross-section of rock types hosting-opal mineralisation. To the
right can be seen the line of the hollow, falling tectonic dislocation controlling the
richest inclusions and lenses with opal mineralisation.
On the radarogram (Figure 2) taken along the upper crest of the pit, the following can be clearly seen:
a) lithologically heterogenous layers shown by notional colouring;
b) tectonic disturbances in the form of slopping lines;
c) entrance points of horizontal mine workings.
eoradars GROT-10 and GROT-11 on australian land.
