The study looked at how to mine coal seams that are close together, focusing on the impact of the rock layers above the coal. By analyzing the process of mining and key factors involved, researchers tested this method in two coal mines. They found that the type and structure of the rock above the coal affect whether this type of mining is feasible. This research helps expand where this mining method can be used, which can help recover more coal in old mines and protect the environment in certain areas.