FARA System
Simple solution for complicated  geological problems
Russian
Over the years, we have accumulated a wealth of experience in using the FARA system in production practice at ore deposits. The following tasks were
solved: searching for sulfide mineralization zones, tracing zones from borehole to borehole, identifying еhe most rich and promising zones for industrial
development, sterilization of the cross-hole space, etc.

Finding new unexplored objects

If there is a borehole network in the exploration area, FARA surveys essentially outline the shape of the conductive bodies. Specifically, FARA is used in
discovering ore bodies, ore-controlled structures or other contrasts in the conductivity of bodies.
 
In this example FARA outlined the conductive zone between the boreholes, which
have no mineralized intersections in the core log. The zone corresponds to a contact
type nickel deposit in the Sudbury Basin.

The survey was carried oud between the boreholes #1 and #2.

As a result, the conducting zone was localized on the right side of the section.
The zone corresponds to the sulfide mineralization intersected by the boreholes
#4, #5 and #6. Borehole # 3 did not intersect the mineralization, which confirms
the pinching out of the zone to the middle of the cut.

Also, an unknown conductive zone was identified in the lower left part of the
section. Boreholel #3 revealed in this area a zone of crushing saturated with
mineralized water, which was taken into account when planning mining
operations in the area.

 
The results of the work to define the Nickel Rim South deposit in Sudbury, conducted in 2002.
The surveys were carried out from the MAC-100G borehole, which intersected two intervals of rich mineralization, to nearby boreholes that did not have
such intersections.

Based on the results of the surveys, a model of the deposite was built. The development of the Nickel Rim South deposit has been carried out since 2009.
In this example, during exploration one of the two boreholes has intersected two sulfide
mineralized zones.

FARA has shown that these zones have elongated character, and both pinch out at some
distance from the other borehole.


Definition of the discovered bodies

If there is only one borehole that intersected the mineralized bodies, FARA may characterize their shapes and extent using the nearest borehole, instead of
additional drilling.
 
Contouring of mineralized zones

FARA can be used to gather additional information in contouring  the discovered mineralization, which may be useful in estimating the resources.
 
The ore zone (central part of the section), intersected by several boreholes was contoured with the use of FARA. Zones, which were discovered by FARA
on the upper part of the section, are controlled by faulting, as indicated by later logging of the boreholes.

In the lower part of the section between the boreholes #1 and #2, the position
of the conducting object, separated by geological data, was specified.

In the lower part of the section between the boreholes #3 and #4, contours of
the known ore body are confirmed.

It is characteristic that the use of the tomographic reconstruction technique
allows to distinguish between the host rocks. In particular, in the section
shown, underlying gneisses and overlapping norites differ distinctly from ore-
controlled Sublayer norites.

New features of the discovered mineralization

FARA reveals previously unknown characteristics of the discovered mineralization. In particular, thickness, boundaries, inclination, pinching of the
mineralization, etc.
 
Sulfide mineralization is intersected by the central borehole.

Boreholes, located nearby have no Intersections of this zone. FARA has
discovered that the mineralization is elongated  but pinches out totally at
some distance from the other boreholes drilled nearby.

However, the distribution character of the zone in the two directions is not the
same. The locations of the thinning, thickness, inclination, and other
parameters were characterized, making it possible to describe the zone
thoroughly.


Heterogeneities inside the mineralization
 
FARA reveals  heterogeneities inside a large mineralized zone, having a contrasting body of conductivity in it.

The drilled boreholes have intersected a weakly mineralized zone. FARA outlined the boundaries of this zone
and discovered a local  more conductive body inside the zone, corresponding to a higher grade of sulfide
mineralization.


Cross-hole space sterilization
 
In widely spaced boreholes, FARA can “see” any body, or a  contrast in
conductivity, thus eliminating the possibility for any sizeable mineralization to
be missed. FARA thus recognizes the presence or absence of the conductive
bodies  in cross-hole space, which may essentially save time and money
during exploration.

One of boreholes intersected a thin mineralized zone. Since the thickness of
the zone is small, further detailed drilling appeared to be unjustified. FARA
sterilized the cross-hole space, by demonstrating the size and extent of the
zone.
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