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STEREOTOMOGRAPHY

Engineering Geology, 20 (1984) 311-324
Elsevier Science Publishers B.V., Amsterdam - Printed in The Netherlands


STEREOTOMOGRAPHY
PHILIPPE G. DOR and ANDRE F. LABOSSIERE
Nancy (France)
Montréal (Québec)
(Received July 14, 1983; accepted after revision June 8, 1984)


ABSTRACT
Dor, Ph.G. and Labossière, A.F., 1984. Stereotomography. Eng.Geol., 20:
311-324.


The following paper presents a new exploration technique called

"stereotomography". Such a technique appropriately combines stereograms

with data from borecores or from drillhole logs. Its purpose will be to show

graphically the general trends of data for structural domains, for sectors, or

for a whole mine. This method has been originally designed for discrete RQD

measurements between boreholes, but it also has many other uses when RQD

is substituted by any other physical or geophysical parameter related to the

rock mass. In their example case, the authors found that such a so-called

stereotomographic technique, supported by a complete structural geology

study, will be decisive in the choice of potential mining sites, since it can

delimit the discontinuity attitudes present inside the rock mass.


INTRODUCTION
The technique we describe in this paper found its source in a dual problem
that one of the co-authors tried to solve when working on a Development
Project in Mexico. Having to design an open pit project for the Cuerpo Uno
at the Las Encinas mine, he had a double challenge to take up. Could he
minimize the waste/ore ratio by steepening the final angle of the excavation,
while at the same time avoiding the potential failure ? In other words: what
is the steepest angle that we can safely reach, and how can we measure it ?

Unfortunately, all of us know that for such a trivial question, there is no
trivial answer. The only applicable way to tackle this problem is to rely on a
conventional structural geology study. But, more often than not, the data
for potential sites are scarce, if not non-existent. In the case of this
prolongation of the principal body named San Pascual, such a problem
happened to be the case ... fortunately this time.


SOME NOTES ON THE RQD
The RQD or "rock quality designation" was invented by D.U. Deere and his
colleagues around 1963 (Deere, 1963). The advantages of such an index
have been assessed by many investigators since then, and numerous works



0013-7952/84/ $ 03.00
© 1984 Elsevier Science Publishers B.V.
© 1984 Philippe G. Dor & André F. Labossière
[ u.s.(c) TXu-162-403, 84-06-05 ]

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