The capabilities of the methods of underground gravimetry and a new guideline - the ground-underground gravimetry are undeservedly forgotten in the present time. A number of failures on a mines of the Verkhnekamsky potassium deposit, which include the flooding of the first and the third mines, led to a fresh look at the problem of geophysical safety of the mining Methods of ground-underground gravimetry for detection of weak areas of the protective layer over the mines are developed and some examples of application are presented. It is shown that the modem methods of processing and interpretation of ground-underground gravity data significantly increase the information value of research and allow to successfully identify zones that are potentially hazardous to development of productive stratum.