大同煤田接触变质煤的煤岩煤质变化规律  

Changes of petrographic characteristics and quality of contact-metamorphosed coals in the Datong coalfield

作　　者：马宏涛 宋晓夏[1,2] 李凯杰 赵金贵[1,2] 章天广[3] 柳建平 MA Hongtao;SONG Xiaoxia;LI Kaijie;ZHAO Jingui;ZHANG Tianguang;LIU Jianping(College of Mining Engineering,Taiyuan University of Technology,Taiyuan 030024,China;Shanxi Key Laboratory of Coal and Coal Measure Gas Geology,Taiyuan 030024,China;Tongmei Datang Tashan Coal Mine Co.Ltd.,Datong 037000,China;115 Coal Geological Exploration Institute of Shanxi Province,Datong 037003,China)

机构地区：[1]太原理工大学矿业工程学院,山西太原030024 [2]煤与煤系气地质山西省重点实验室,山西太原030024 [3]同煤大唐塔山煤矿有限公司,山西大同037000 [4]山西省煤炭地质115勘查院,山西大同037003

出　　处：《煤田地质与勘探》2020年第2期99-105,共7页Coal Geology & Exploration

基　　金：国家自然科学基金项目(41802191)。

摘　　要：大同煤田石炭-二叠纪煤层中的岩浆岩侵入造就了大量的接触变质煤,降低了煤的利用价值。为了详细探讨岩浆岩体距煤层距离对煤的物理化学性质影响,通过对塔山井田5222巷的辉绿岩岩墙及周围煤层的地质编录、系统采样,及煤样的煤岩学分析、工业分析和元素分析,研究接触变质带的煤岩煤质特征。结果表明:接触变质煤在高温条件下生成各种天然焦微观结构,如镶嵌结构、流动结构、热解碳等;侵入体对煤层的瞬时加热显著提升了热变煤的煤级,镜质体最大反射率由正常煤的0.67%~0.87%增至接触变质煤的0.94%~3.67%;接触变质煤中水分含量和灰分产率显著升高,挥发分产率降低;靠近岩墙的煤样中C含量上升,H、N、O含量下降。综合分析认为,岩墙接触变质作用对煤层的影响范围约4.5 m,即1.25倍岩墙宽度,而严重变质带为1.6m。研究成果为煤的开采利用评价提供依据。Igneous intrusions in the Datong coalfield caused a considerable amount of contact metamorphosed coal,reducing the industrial value of coal.The effect of a dike in roadway 5222 in Tashan coal mine was determined from analysis of 16 samples collected near the intrusive body.Microscopic and macroscopic observation,proximate and ultimate analysis were used to determine the petrographic characteristics.The results demonstrate that contact-metamorphosed coal experienced significant thermal alteration during intrusive event.Microscopically,various natural coke microstructures,such as mosaic structure,flow structure and pyrolytic carbon were formed under excess heat;instant heating for coals resulted in the elevation of coal ranks,the maximum reflectance of vitrinite increased from 0.67%-0.87%of the normal coal to 0.94%-3.67%of the contact metamorphosed coal;In the contact-metamorphosed coal,the moisture content and the ash yields increased remarkably and volatile yield decreased;In coal samples near dikes,C content increases,H,N and O content decreases.From the comprehensive analysis,it was inferred that the influencing range of the contact metamorphism of the dikes for coal seams is within 4.5 m,1.25 times of the dike thickness,1.6 m in a severely metamorphosed zone.The research results provided the basis for assessment of coal mining and utilization.

关 键 词：辉绿岩 岩墙 接触变质作用 煤岩学 塔山井田 大同煤田 

分 类 号：P618.11[天文地球—矿床学]