Abstarct: In the late 20th century, the topic of sustainable development was introduced with the aim of creating a balance in the three economic, social, and environmental areas. Long-term planning and final pit design in open-pit mining require, in addition to technical studies, a proper assessment of environmental, social, and economic conditions as the three main pillars of sustainable development. In most cases, mining has negative environmental impacts on the region and puts human health, organisms, and water at risk. On the other hand, the positive economic and social impacts have led to increased social welfare in the region, increased business, reduced addiction, improved living standards, and GDP growth. So far, many models have been introduced to assess the level of sustainable development in many industries, including mining. Among the introduced models, semi-quantitative models in the science of sustainable development have gained more popularity among the academic community. Semi-quantitative sustainable development assessment models use questionnaires and expert opinions to examine the level of sustainable development. However, most models have three fundamental flaws. First, these models are limited to a single number indicating the level of sustainable development and are unable to assess the level of sustainable development for each indicator. Second, these models only provide results and do not provide a plan to improve the level of sustainable development in the case under study. Third, most models have not incorporated new parameters resulting from increased knowledge and technology in sustainable development into their models, considering the imperative concept of sustainable development. For this reason, in this doctoral dissertation, an attempt was made to develop an expanded model baxsed on semi-quantitative methods, integrating this model with strategic management and adding new parameters resulting from increased awareness, knowledge, and technology to address the mentioned flaws. The expanded model is capable of calculating the sustainability level for each indicator separately and also, baxsed on the principles of strategic management, provides the optimal plan to improve sustainable development indicators according to the concept of sustainable development and the three-pillar frxamework in the short, medium, and long term. Ultimately, to evaluate the overall level of sustainable development, the weight of each indicator was examined baxsed on the political, social, geopolitical, cultural, and economic conditions of the studied mine, and an overall sustainability level for the mine under study was calculated considering the mentioned conditions. Subsequently, the expanded model was examined for evaluation in the Mehdiabad lead and zinc mine. The results showed that the level of sustainable development for each of the environmental, social, and economic indicators, as well as the overall level of sustainable development in this mine, was 0.231, 0.230, 0.016, and 0.147, respectively. Additionally, with the presentation of solutions and strategic planning for this mine, it is expected that by considering the aforementioned factors, the overall level of sustainable development in this mine in the short, medium, and long term will be 0.199, 0.387, and 0.553, respectively. In another sense, it is expected that the level of sustainable development in the Mehdiabad lead and zinc mine will progress from a weak sustainable level to a good sustainable level in the long term. To validate the Mehdiabad mine model, it was examined using the Phillips method of sustainable development assessment. The validation result showed a sustainable development level in the Mehdiabad lead and zinc mine using the Phillips method of 0.155, which was within an acceptable range of the expanded model. Therefore, this model can be introduced as the most comprehensive model for sustainable development assessment in all industries, especially the mining industry. With the integration of strategic management with sustainable development in the expanded model, we are witnessing a revolution in sustainable development assessment methods. ‌