Abstarct: The role of mines and resources in the economic growth of any country is undeniable. Undoubtedly, the exploitation of country's mines is a very positive and important factor in economic growth and development. The process of underground mining, which is associated with disruption of groundwater hydrogeology, causes the entry of water into the Underground space.Groundwater flow into the tunnel can pose many problems during drilling and exploitation. therefore important to estimate the amount of water flow in the tunnel from an executable point of view, and this requires understanding the hydrogeological conditions of the tunnel surrounding areas. Although several methods have been proposed to estimate the amount of water flow into the tunnel, there is no complete method for accurately calculating the amount of water flowing into the underground space. The number one tunnel of the Angouran lead and zinc mine is 1190 meters long, most of which is limestone and part of it is schist. In this research, after analyzing the results of allogeneic tests carried out in the area, the role of geological structures such as faults, open fractures, etc. was investigated. Then, with the analytical and experimental methods estimated the flow rate of the inflow into the tunnel and compared with the actual value. From the analytical relationship, Karlsrud relation and Heuer's experimental method, the results were close to the actual value. Therefore, an accurate estimation of the water flow to the tunnel will be very useful in designing, determining the methods of implementation, and predicting costs. Cost estimation studies are an important part of the feasibility studies of mining projects and play a major role in economic or non-economic project introduction. Documented and reliable estimates of costs and thus project revenue estimates form the basis of economic analysis and investment decision making. Since no model has been found to focus solely on the cost of underground dewatering, a new model has been proposed to calculate the dewatering costs of underground space baxsed on the amount of water flow. Simplicity, availability of cost effective parameters and calculations baxsed on the amount of water flow the underground space can be the benefits of this model. Finally, the cost of dewatering of Anguran lead and zinc mine was estimated using the model.