<p>After decades of operation, subsidence in the metre range has occurred above a solution mining field on the periphery of the City of Maceió, with maximum subsidence rates of 25 cm/year. There are several reasons for this unusual behaviour: the salt deposit at a depth of around 900–1200 m is formed by alternating layers of rock salt and shale, which has a strength of less than 50% of that of rock salt. In addition, the pillars between the caverns in the centre of the field turned out to be too small, and the salt back above the roof of several caverns was not sufficiently stable. As a result of fractures in the cavern roofs, numerous caverns had developed up to the top of the salt and in some cases several hundred metres into the overburden. The thickest overburden formation, Poção, with around 400 m, has relatively low strength. Decisive for the strength and subsidence behaviour of the overburden is the small-tectonic fragmentation with pre-existing mechanical weakness planes. These are responsible for the formation of the subsidence trough with steep flanks. Based on discontinuous HM-coupled 2D and 3D models with shear strain softening at joints and bedding planes, the subsidence mechanism and the potential risk of sinkholes developing above deep caverns were investigated. The development of sinkholes is predestined by a low level of confinement (horizontal stress) in the overburden, as is the case in the Maceió deposit in a graben structure, and by the role of fluids in controlling the failure mechanism in the formation of chimney-like fracture tubes in the overlying rock formations. At the end of 2023, a sinkhole occurred above the centre of the brine field, which the seismic monitoring system had forewarned of weeks earlier.</p>