Abstract

Six structural domains were defined using data from acoustic televiewers and oriented boreholes as part of the reopening of the old Aznalcóllar mining site in Sevilla, southern Spain, by Minera Los Frailes (MLF). Additionally, geotechnical subdomains were defined within each structural domain, classifying the subdomains based on geotechnical parameters obtained from the geotechnical logging of boreholes and through correlations. The methodology used to define the domains allows mine design and planning to be done with enough accuracy to determine the underground excavation needs and the systematic methodology. The main source of this new structural information was acoustic borehole image televiewers (ABI) and, on a much minor scale and as a complement for ABI data, oriented boreholes. This paper describes the methodology used for this definition, some of the challenges encountered during the investigation, the main results obtained and the utility of these defined structural domains in the development of the MLF mining site reopening. Additionally, a preliminary approach to an updated methodology in the definition of structural domains with the combination of televiewer data, both acoustic and optical, with data obtained from other downhole probes is also included.

Abstract

The estuarine sediments around the head of the Forth estuary deposited during and after the Flandrian interglacial are an important, economically productive regional soil horizon in Scotland. The soil has been extensively studied locally (Hight et al., 1992) at the Bothkennar EPSRC site however, to the authors’ knowledge seismic dilatometer testing using Marchetti’s Medusa apparatus has never been used to characterise the material. Taking data from a number of sites and using an automated Medusa seismic dilatometer apparatus, a complementary contribution to the characterisation of the site which includes some comments on spatial variability of the material and other observations are presented.