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discrete three-dimensional RQD data of intersecting lines as little dots or
characters. Secondly, a histomogram, in the same size as the former and this
was, in a way, a histogram, and where the number of elements having a
common trend and plunge were shown. Both projections were essential
to the process. On the stereotomogram, the results of all weighted RQD
values sharing a common attitude were printed, while on its counterpart
of the same size, the histomogram, the number of those values having the
same polar coordinates were printed.
Fig. 1 shows the RQD values, on a Schmidt net ("falsilla de Schmidt"), of a
deposit to be analyzed in the future and about which no trials had been
made at the time of the study. This deposit was named Cuerpo Uno or
Body No. 1 and was located at the Las Encinas mine in the State of Jalisco.
Such a figure implied, for the Total Zone ("Zona T"), 154 data ("datos") drawn
from 34 boreholes ("barrenos") which represented 11,442 pairs of RQD data
("pares de datos"). However, those 11,442 weighted RQD values of 20 m long,
taken each 40-m multiple from the borehole collar, represented only 50 %
of available information, while 36,165 intersections would imply 100 %
information for 6,500 m of drill cores. Nevertheless, the importance of such
a sampling (11,442) seemed to us highly sufficient to infer the probable
trends of low end high isovalues necessary for the interpretation.
The legend below the stereotomogram differs from its partner presented
in Fig. 2 in that a second row shows 10 equal range classes of RQD, from
A to J. Such classes are made with the weighted RQD values shown on the
net. The usefulness of such a row lies in the fact that the distribution of
RQD can be seen easily and in the possibility of pinpointing quickly the
lowest classes, without having to search for other values not present on the
stereoplot. Finally, the last line specifies the percentage of the net held
by RQD characters ("% de la superficie total"), while the words in parentheses
reveal the number of points used to draw the net itself (2,405).
Before explaining the use of such figures, we would like to say a few
words about the last two terms of the common part of stereotomograms
and histomograms, and also about the weathering problem in the region under
study. At the beginning of the investigation, in an earlier version of the
program, we used a "hydraulic restriction" ("restr hidr"), rather than a
weighting or a compositing later used for dealing with the length of the
imaginary line connecting two 20-m equal intervals of paired holes. However,
the validity of such an artifact soon appeared to be superfluous by comparison
with an inverse distance squared (IDS), or even with an inverse distance
exponential (IDE). Such a so-called hydraulic restriction consisted of an
arbitrary fixed cut-off limit in meters for the length of virtual intersecting
lines. When it exceeded that limit, the computer did not use the corresponding
RQD value in performing the final work. Meanwhile, such a gadget
remained in our program because we found it handy for a rapid investigation
of unknown regions which would eventually require further searches.
As regards the last term of the common part of all figures ("correc litol"),
it was used as a milestone or a landmark, and this indifferently, for
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