High-extraction coal mining in Illinois: effects on crop production, 1985-1987

The impact of coal mine subsidence-induced effects (SIE) on yields in 1985, 1986 and 1987 in Illinois was investigated. Five study areas were selected in three counties in southern Illinois, representing longwall (LW) and high-extraction retreat (HER) mines, as well as unmined control areas. Study areas were photographed from the air in early, mid-, and late growing season in 1985 and early and mid-growing season in 1986 and 1987. After the photographs were analyzed, areas deemed to have SIE were marked on them. Three classes of SIE were established: slight, moderate, and severe. In the fall of each year, sites representing all SIE classes, including unaffected control areas, were harvested for corn yield sampling. No significant corn yield difference was found between the control and slight SIE class in any year. Significant yield reductions were noted for the moderate class: 52% in 1985, 56% in 1986, and 22% in 1987 (average of 43%). Significant reductions were also found in the severe class: 95% in 1985, 99% in 1986, and 91% in 1987 (average 95%). -from Authors