Workplace safety has become a major concern in the activities of any mining company. It has even become a classification criterion in the listing of companies on the stock market.Mining is one of the most risky modern industrial activities. The instability of underground structures (chambers, galleries) is a problem encountered by many mines. It should be noted that any rock mass, whatever its history and location, has discontinuities, which may be pronounced, invisible, cemented or open. The geo-structural study and the geo-mechanical classification of the rocks have allowed us to classify the terrain in which a mining structure can be installed without collapsing, and also to make a good choice of support.