There are several points of view on the conditions of slab formation. One group of researchers sees the main cause of layer formation in geotectonic fluctuations of the Earth's crust, which control the process of sediment accumulation. Other researchers consider the main cause of layer formation to be a change in the conditions of sediment formation as a result of changes in the physical-geographical regime; at the same time, they do not attribute significant importance to the geotectonic factor.

Fracture and displacement of the formation is a geological phenomenon, in each specific case, depending on the geological situation, possessing special geometric forms. Geometric classifications of fractures are numerous and their complexity is diverse, but all of them are only a way to make sense of the variety of fracture shapes. In order to search for a displaced part of the formation, not only normal but also displaced wing data are needed. Therefore, geologic setting data common to both wings are of particular importance to the search for the offset part of the reservoir.

Insignificant changes in the occurrence of declining seams often leads to losses of coal in the subsurface and. creates sometimes difficulties in the use of mining mechanisms, so the clarification of hypsometry of declining seams is one of the important tasks of mine geology.