Silvia Riccucci

Geological Application of UAV Photogrammetry and Terrestrial Laser Scanning in Marble Quarrying (Apuan Alps, Italy)

Workplace safety in quarries can be evaluated and improved through an accurate risk assessment of mining activities. Rock slopes stability is dominantly influenced by the structural setting which, in combination with exploitation methods, affects the risk. This paper describes studies carried out in the Apuan Alps, where several quarry walls reach hundreds of meters in height and are dominated by natural slopes with complex morphology. Aim of the present paper is to determine the detailed structural-geological setting of a quarry wall and to identify potentially unstable zones. In such an environmental context, data obtained from engineering-geological surveys, collected at the foot of the slope and along the wall by climbing technicians, may be used for rock mass characterization. This data, which holds important statistical value, has been integrated with other info coming from a terrestrial photogrammetric survey, that was realized using an unmanned aerial vehicle, and from terrestrial laser scanning. The stereoscopic and high resolution images and the 3D model from point clouds have been processed and interpreted in order to provide a deterministic information of the complete slope setting. The geometrical and geo-engineering data was utilized for a stability analysis carried out through a 2D numerical modelling based on the distinct element method. Results of this study have been used to assess the safety conditions necessary to continue the exploitation activities and, eventually, to plan for proper remediation.

Geological 3D modeling for excavation activity in an underground marble quarry in the Apuan Alps (Italy)

The three-dimensional laser scanning technique has recently become common in diverse working environments. Even in geology, where further development is needed, this technique is increasingly useful in tackling various problems such as stability investigations or geological and geotechnical monitoring. Three-dimensional laser scanning supplies detailed and complete geometrical information in short working times, as a result of the acquisition of a large number of data-points that accurately model the detected surfaces. Moreover, it is possible to combine these data with high quality photographic images so as to provide important information for geological applications, as follows. A working approach, that combines terrestrial laser scanning and traditional geological surveys, is presented. A three-dimensional model, that includes information about the geological structure in an underground quarry in the Apuan Alps, is realized. This procedure is adaptable to other geological contexts, and because of its operating speed and accuracy it is invaluable for optimal excavation, in which a proper planning of quarrying activity is vital for safety and commercial reasons.

Integration of Geotechnical and Remote Monitoring Systems for the Analysis and Control of Ground Deformation in Marble Quarrying (Apuan Alps, Italy)

Workplace safety in quarry sites can be evaluated and established through an accurate monitoring of mining activities and slope stability. This last is dominantly influenced by the structural setting which, in combination with exploitation methods, affects the risk. The present paper shows the applied methodologies and the preliminary results obtained from an integrated monitoring system implemented in the Apuan Alps, within a quarry characterized by a buttress shaped remnant of previous excavation activities and accessible from 3 sides. In 1997, a rock fall event occurred in a neighbouring area of the buttress causing the interruption of quarrying activities. With the purpose of controlling the buttress stability, preserving safety conditions, planning proper remediation works and continuing exploitation activities, various monitoring systems have been installed during the years: this paper describes the 3 more recent systems that have been operating for more than 1 year. The instrumentation consists of geotechnical monitoring sensors composed by extensometers and crack-meters, and two topographic systems represented by a terrestrial interferometer and a robotic total station. Results from the 3 monitoring systems highlighted few critical zones whose presence was already known and precautionary measures had already been adopted; their geo-mechanical character is still under study with the aim of establishing the thresholds of risk that separate the natural rock behaviour from any probability of failure.

Topographic and geological mapping in the prehistoric area of Melka Kunture (Ethiopia)

This paper describes the results of topographical and geological surveys carried out at the prehistoric area of Melka Kunture (Ethiopia) in order to produce new detailed maps at a scale of 1:10,000 for supporting archaeological investigations and providing good reference cartography during fieldwork. The topographic support was created from the stereorestitution of two pairs of Standard Stereo IKONOS-2, 1m pan-sharpened satellite imageries covering an area of about 100km2. The topographic map was utilized both for the geological survey and for the interpretation of the palaeo-environmental evolution of the site based on present geomorphological features. The aerial triangulation of satellite images, performed using ground control points measured using differential GPS surveys, allowed the stereoscopic visualization of the area and the creation of a digital elevation model and orthophotos. These results were a useful cartographic aid during the geological survey when all the outcrops along gullies, streams, roads and rivers were inspected and documented through additional in-depth field checks. The geological map was created and refined using the digital elevation model and photointerpretation of stereo and orthoimageries, making it possible to fully identify the geological boundaries between formations and recognize geomorphological features.