An rescaled range analysis on the characteristics of coal seam development in the Eastern depression

The characteristics of coal seam development, and the prospects of a favorable coal-forming area, were evaluated for the Liaohe Basin located in China. The Number 3 and Number 9 coal seam thickness series from 60 nearly equally spaced bores in the Eastern depression of the Liaohe Basin were examined by a rescaled range analysis. The results indicate that the Hurst exponents of the Number 3 and Number 9 coal seam thickness series are 0.69 and 0.68, respectively. This suggests the presence of persistence. As the bore spacing increases the Hurst exponent of the Number 3 series gradually decreases (H changes from 0.69 to 0.52) and shifts from persistence to randomness. The Hurst exponent of the Number 9 thickness data gradually increases (H changes from 0.68 to 0.91) and always shows the characteristic of persistence. A combination of geological characteristics and the series data allow the conclusion that it is more suitable for the Number 9 coal seam to form in the Northeastern part of the Eastern depression than the Number 3 coal seam.