17 pages et 7 figuresNational audienceThe conditions of the stability of the drifts excavated in the Vosges sandstones, that might be modified by overburden weakening and/or flooding of drifts, have been analysed. The effects of potential instabilities on the surface level have also been quantified. In the worst case, the performed analysis predicts formation of a sinkhole at soil surface only if the drifts are very close to the surface and in case the mechanical properties of the sandstones and those of natural discontinuities are very poor. Beyond eight meters of depth, evolution of collapse arch is stopped prior to reaching soil surface, as a matter of dilatancy of collapsed strata. The “Houillères du Bassin de Lorraine” uses these results for safety assessment of the drift belonging to mining infrastructure such as old drift FALCK driven in 19th century for water seepage
