The article discusses the experience of drilling and blasting operations in the conditions of high water cut of the rock massif, it also presents practical experience in modeling and forecasting water inflows into workings. By the example of the Koashvinskoe deposit, the problems of work in conditions of high water cut of the rock mass leading to the collapse and silting of drilled boreholes are considered. The article presents calculations showing the effectiveness of the drainage systems for lowering the groundwater level of a prepared rock mass section. The paper provides a rationale for the optimal mass of bottom charges for the preparation of drains in the rock mass, depending on the water saturation of the mass and the grid of drilled boreholes.