渭北煤田煤岩层深部异常风化的成因类型

Genetic types of abnormal weathering of deep-seated coal-series strata in Weibei Coalfield of Shaanxi Province

目的 探讨渭北C-P煤田深部煤岩层异常风化的成因类型。方法 通过大量井下地质调查、煤岩样品鉴定与分析,对所揭露的众多煤岩层风化点进行了研究。结果 渭北煤田存在岩溶塌陷裂隙导通风化型、断裂垂向导通岩溶风化型及断裂横向导通古窑风化型等3种深部风化作用成因类型;来自煤系底部与外界相通的奥陶系石灰岩溶洞中的空气及煤系浅部与古窑相通的空气是引起深部煤岩风化的主要因素,煤层上下部含水层及煤层本身与顶、底板岩石中的黄铁矿结核为促使风化作用的次要因素。结论 该研究为煤岩层深部风化带预测提供了依据。

Aim The study on the genetic types of abnormal weathering of deep-seated coal-series strata in Weibei Permo-Carboniferous(C-P) coalfield of Shaanxi Province is of great practical significance to guide the effective production of coal mines.Methods Through a series of geologic investigation on coal faces of Weibei coal mines ,the identification and analysis of coal and rock samples,a great deal of exposed geologic information from the weathering areas is studied.Results Three types of the genetic models of deep-seated weathering are put forward,which are respectively karst collapse fracture up and down connecting weathering types,vertical fault connecting karst weathering types and lateral fault connecting ancient coal pit weathering types.The contact of deep-seated coal-series strata with the air from the karst cave of Ordovician System and the contact of shallow coal-series strata with the air from anticent coal pits are the main weathering cause ,while the aquifers underlying the coal bed and overlying the coal bed and the pyrite nodules in the coal bed and its roof and bottom formation is the secondary cause impelling weathering . Conclusion It provides theoretic basis for forecasting deep coal bed weathering zone.