Hydrogeological Risk and Mining Tunnels: the Fontane-Rodoretto Mine Turin (Italy)

Authors: Paola Gattinoni, Laura Scesi, Elena Cerino Adbin, Daniele Cremonesi

Abstract:

The interaction of tunneling or mining with groundwater has become a very relevant problem not only due to the need to guarantee the safety of workers and to assure the efficiency of the tunnel drainage systems, but also to safeguard water resources from impoverishment and pollution risk. Therefore it is very important to forecast the drainage processes (i.e., the evaluation of drained discharge and drawdown caused by the excavation). The aim of this study was to know better the system and to quantify the flow drained from the Fontane mines, located in Val Germanasca (Turin, Italy). This allowed to understand the hydrogeological local changes in time. The work has therefore been structured as follows: the reconstruction of the conceptual model with the geological, hydrogeological and geological-structural study; the calculation of the tunnel inflows (through the use of structural methods) and the comparison with the measured flow rates; the water balance at the basin scale. In this way it was possible to understand what are the relationships between rainfall, groundwater level variations and the effect of the presence of tunnels as a means of draining water. Subsequently, it the effects produced by the excavation of the mining tunnels was quantified, through numerical modeling. In particular, the modeling made it possible to observe the drawdown variation as a function of number, excavation depth and different mines linings.

Keywords: Groundwater, Italy, numerical model, tunneling.

Digital Object Identifier (DOI): doi.org/10.5281/zenodo.1078703

References:

[1] A. Dematteis, G. Kalamaras, A. Eusebio, "A systems approach for evaluating springs drawdown due to tunneling", in "World Tunnel Congress AITES-ITA" Vol. 1, Patron, pp 257- 264, 2001.
[2] S. Loew, "Groundwater hydraulics and environmental impacts of tunnels in crystalline rocks", in "Meccanica e Ingegneria delle rocce - MIR", Torino, Italy, pp 201-217, 2002.
[3] L. Scesi, P. Gattinoni, Water Circulation in Rocks, Springer, 2009, p. 165.
[4] A.W. Harbaugh, E.R. Banta, M.C. Hill, M.G. McDonald, The U.S. Geological Survey modular ground-water model - User guide to modularization concepts and the groundwater flow process, Open-file Report 00-92, USGS, Boulder, Co, 121p., 2000.