The occurrence scope of abandoned gob methane is obtained based on the three-zone theory of overlying relieved gas delivery. A method to calculate the height of the gas conductive fracture zone and the height of the gas pressure relief and desorption zone is given by considering overlying key strata structure, mining height, and workface length. According to the sources of abandoned gob methane, a model for estimating abandoned gob methane reserves based on the three-zone theory of overlying relieved gas delivery is established. According to the established reserves estimation model, abandoned gob methane reserves of K8108 fully mechanized caving workface are 31.78 million m3.