SHALLOW SEISMIC-REFLECTION IN A MINE GALLERY

The technique of seismic reflection was used to survey the mineral deposits in a copper mine exploiting the sulfide minerals galena, pyrite and chalcopyrite. This approach required the adaptation of seismic reflection techniques to the specific features of the mine, which are thin mineral-bearing layers, variable thickness of overlying strata, and innaccessible rock faces. Field measurements were made according to a four-fold multiple coverage. After an initial survey, we were able to develop a model that allowed the evaluation of the ''optimal offset'' based on synthetic traces. Deconvolution considerably improved the procedure, together with the definition and the ability to determine the depth of the upper contact of the mineral deposit. Finally, the application of complex traces analysis, mainly of instantaneous amplitude, permitted us to specify the degree of continuity in the mineral horizon under survey.