The study looked at how the ground above a coal mine can shift when different mining methods are used together. By combining theory, measurements, and computer simulations, the researchers found that the roof above the coal mine can have a big structure at the top and a small one at the bottom. This can make the support beams less stable and increase the risk of the roof collapsing. The area where the coal is being mined can also have a lot of stress, leading to more coal breaking off and the roof becoming unstable.