``Structural analysis'' is the name given to the procedure of characterizing
the structures of the spatial distribution of the variables considered (e.g.,
grades, thicknesses, accumulations). It is the first and indispensable step of
any geostatistical study. The variogram model acts as a quantified summary
of all the available structural information, which is then channeled into the
various procedures of resource and reserve evaluation. Thus
can be
regarded as injecting extensive geological experience into the sequence of
studies involved in a mining project.
In the proving of any mining project, it is imperative to have good
communication between all the departments involved (geology, mining
techniques and economy, processing). It is a waste, for instance, to have a
geologist carry out an excellent study of geological structures, only to be
followed by a project engineer evaluating resources by such arbitrary
procedures as polygons of influence or inverse-squared distance weighting.
Such evaluations are independent of the deposit and its geology, and make
no distinction, for example, between a gold placer deposit and a porphyry-copper
deposit. The variogram model
can help in this essential
communication between the geologist and the project engineer.