Providing an approach to calculate a suitable panel width for the longwall mining method is considered considering both the technical and economic factors. Based on the investigations carried out, a technical-economic model is proposed to calculate a suitable panel width. The proposed model is a combination of the rock engineering system-based model and the technical relationships to estimate the expected actual face advance rate of the longwall panel and also the economic relationships to determine the operational costs. Applying the technical conditions to the presented model is conducted by the vulnerability index of the advancing operation, which considers the face advance rate as the main important factor that controls the operational costs of the longwall face. The performance evaluation of the presented model is possible by the recordable field data, which is one of its advantages. This process is carried out by a case study, and the results obtained indicate that the developed approach can provide an applicable tool to calculate a suitable panel width.