Occupational Safety and Health in Tunnelling in Rocks Formations Potentially Containing Asbestos: Good Practices for Risk Assessment and Management

Abstract

Abstract:In tunnelling operations, Occupational Safety and Health (OS&H) and Environmental Protection of the areas close to the tunnel portal become even more critical in case of rock formations potentially containing asbestos, quartz, radioactive elements, etc. In order to limit the workers' exposure and the environmental impact becomes in these cases of paramount importance to preliminarily analyze and quantify the possible presence of the pollutants in the rock and, if necessary, to implement suitable measures to avoid/minimize their emission from the winning and mucking operations. However, in case of asbestos minerals, to obtain reliable results from the preliminary analysis is a challenging task, due to the complex patterns of occurrence of asbestos within the host rock. Consequently, the definition of special monitoring, alarm and control systems is essential during the tunnel excavation. The paper summarizes the results of a thorough study aimed at defining the most suitable monitoring techniques in uncertain situations and the residual criticalities, essentially due to the delay between the beginning of the pollutant release at the tunnel face and its detection. The final part of the work deals with the possible innovative prevention solutions suitable to minimize the previously mentioned delay and ensure the safety of the workers along the time necessary to stop the activities and evacuate the tunnel, on hold of the activation of a special "asbestos" organization.

Airborne asbestos fibres monitoring in tunnel excavation

“…However, naturally occurring asbestos (NOA) deposits contain intermixed phases of different mineral polymorphs, chemical compositions and fibre morphologies, which may lead to variable analytical results (Wagner, 2015). Tunnelling crosses natural rock bodies that often show, at least on a local scale, characteristics of dishomogeneity, therefore, in the case of underground infrastructures construction, the effect of random compositions can be much greater than in other industrial activities due to the nature of the input data (Labagnara, 2016). III) EU directives and Italian legislation recommend the WHO method in Phase Contrast Microscopy (PCM) for measuring asbestos in workplaces (WHO, 1997).…”

“…V) The delay between the occurrence of airborne asbestos fibres and its detection, is not overcome by any technology at the moment. A thorough investigation proved that no instruments suitable for such measurements are to date available on the market and those under development are incompatible with the temperature, humidity and pollution conditions typical of the tunnelling (Stopford, 2013;Labagnara, 2016).…”

Occupational Safety and Health Improvements through Innovative Technologies in Underground Construction Sites: Main Trends and Some Case Histories

“…The literature relating to field experiments aimed at the introduction, in the underground of articulated systems of exhaustive and integrated knowledge in real time, of the operational scenarios and their internal and external interconnections that are endowed with the capacity for direct self-correction of deviations resulting from various causes (including human error), is relatively limited. One of the greatest problems in this regard, linked to the very nature of the activity, is the objective impossibility of forecasting some critical parameters with the desired detail [23].…”

“…Technological and organizational innovation have been promoted since the exploratory works and have generated some shared standards on all construction sites [22][23][24][25][26][27].…”