Based on analysis of a large data set and supplementary sampling and analysis for hazardous trace elements in coal samples from the Huainan Coalfield, a generalized contrast-weighted scale index method was used to establish a model to evaluate the grade of coal cleanliness and its regional distribution in the main coal seam (No. 13-1) The results showed that: (1) The contents of Cr, Mn and Ni in the coal seam are relatively high and the average values are greater than 20 μg/g. The contents of Se and Hg are at a high level while most other trace elements are at normal levels. (2) The cleanliness grade of the coal seam is mainly grade III–IV, which corresponds to a relatively good-medium coal cleanliness grade. However, some parts of the seam are at grade V (relatively poor coal cleanliness). (3) Coal of relatively good cleanliness grade (grade III) is distributed mainly in the regions corresponding to the Zhuji-Dingji-Gubei coal mines and in the eastern periphery of the Panji coal mine. Coal of medium cleanliness (grade IV) is distributed mainly in the regions of the Panji-Xiejiaji and Kouzidong coalmines. Relatively poor grade coal (grade V) is distributed in the southwest regions of the coalfield and the contents of Cr, As and Hg in coal collected from the relatively poor coal cleanliness regions often exceed the regulatory standards for the maximum concentration limits.

在对淮南煤田大数据集进行分析，对煤样中有害微量元素进行补充采样分析的基础上，采用广义对比加权比例指数法建立了评价煤炭清洁度等级及其区域分布的模型。结果表明：（1-13）主煤层中Cr，Mn和Ni含量较高，平均值大于20μg/ g。硒和汞的含量较高，而其他大多数微量元素的含量均处于正常水平。（2）煤层的清洁度等级主要是III–IV级，这对应于一个相对中等程度的煤炭清洁度等级。但是，煤层的某些部分为V级（相对较差的煤炭清洁度）。（3）清洁度相对较好的煤炭（三级）主要分布在与诸暨—鼎集—古北煤矿相对应的地区和潘集煤矿的东部边缘。中度清洁度（IV级）的煤炭主要分布在潘集-谢家集和寇子洞煤矿地区。相对较差等级的煤（V级）分布在煤田的西南地区，从相对较差的煤炭清洁度地区收集的煤中的Cr，As和Hg的含量经常超过最大浓度限值的监管标准。