[Abstract] We've studied the conditions about dimensions and support ofan underground mine of roofing slate in Galice, worked by rooms with continuous pillars. The rock mass was characterized by the empiric and analitic methods, calculating the stable pillar wide along the mine by the theory of attributed area and by a model of finite elements, where the breaking criterion ofHoek and Brown was applied. The result was a parabolic relationship between pillar wide and mine length. Stability studies in an isolated stope give an elastic performance on the periphery of the room, without tractions. Although the stability ofthe mine is good, a systematic support is recommended on the basis of bolts, that will be reinforced with projected concret at the top, and a singular treatment of the detected wedges
