The characterization of the physical and chemical properties of coal on a standard provides an understanding of its characteristics towards spontaneous combustion. The trend of linear relationships between coal recording standards (% air-dried (ad), % dry (db) and % dry ash free (daf) basis) of 30 selected coal samples from the Witbank coalfields and spontaneous combustion liability indices were evaluated. The spontaneous combustion liability indices of these samples were evaluated by crossing point temperature (XPT), Stage II Slope, FCC (Feng, Chakravorty, Cochrane) and the Wits-Ehac tests, while the coal properties were determined from the proximate and ultimate analyses. The results obtained from these coal properties were related to different liability indices to develop trends of linear relationships using regression analysis. The ad basis indicated higher correlation coefficients than the db and daf basis for the XPT and FCC index, while the daf showed higher correlation coefficients than the ad and db basis for the Wits-Ehac index. It was found that the trend of linear relationships of these coal properties differs from one liability index to the next. The XPTs showed a better trend followed by the Stage II Slope on the coal properties among the spontaneous combustion liability indices evaluated.

根据标准对煤的物理和化学性质进行表征，可以了解煤的自燃特性。评价了来自威特班克煤田的30个选定煤样品的煤记录标准（风干百分比（ad），干粉百分比（db）和干粉尘百分比（daf）和自燃指数）之间的线性关系趋势。通过交点温度（XPT），第二阶段坡度，FCC（Feng，Chakravorty，Cochrane）和Wits-Ehac试验评估了这些样品的自燃指数，而煤的性质则由最近和最终的分析确定。从这些煤的性质获得的结果与不同的责任指数相关，从而通过回归分析得出线性关系的趋势。对于XPT和FCC指数，ad基准显示的相关系数高于db和daf基准，而对于Wits-Ehac指数，daf显示的相关系数高于ad和db基准。已经发现，这些煤特性的线性关系的趋势从一个责任指数到另一个责任指数是不同的。在评估的自燃指数中，XPT表现出更好的趋势，其次是第二阶段的煤质坡度。