Researchers studied how coal pillars behave when mining coal in shallow areas with thin rock layers and strong pressure. They looked at how these pillars react to the mining process to better understand their stress patterns. They found that the stress in the pillars is not evenly distributed, forming peaks and low-stress areas. The stress is higher on the side where the mined coal goes compared to the other side. There is a particular low-stress zone around 8 meters wide between these high-stress areas. Based on their findings and simulations, they determined that setting the coal pillar width at around 20 meters is a good choice for safety and efficiency.