山西煤下铝土矿勘查开发主要地质问题及开采条件分析

山西石炭-二叠系煤下铝土矿在全省含煤地层广泛分布,矿体平均厚度1～3 m,铝硅比5左右,随埋深增加矿体硫含量增高。矿体沉积基底主要为奥陶系峰峰组灰岩,少数为马家沟组和寒武系凤山组地层。沉积盖层北部为厚层灰岩,中部为灰岩泥岩互层,南部为薄层灰岩和泥岩。山西煤下铝土矿矿体形态复杂、跨采空区、顶板维护困难、水文条件复杂。勘查阶级首先要查明矿体基底构造形态、矿体赋存范围、上部采空区的空间赋存特征、富水性圈定有利成矿区;煤矿建设和生产阶段主要查明工程地质条件,闭坑煤矿首先要查明采空区范围和积水范围以及瓦斯地质条件;开发阶段需充分考虑水文地质条件,同时做好顶板支护。

Main geological problems and mining condition analysis for the exploration and development of bauxite under coal bed in Shanxi Province

Carboniferous-Permian Bauxite bauxite under coal bed is widely distributed in coal-bearing strata in Shanxi Province. The average thickness of the ore body is from 1 to 3 m, and the ratio of aluminum to silicon is about 5. The sulfur content of the ore body increases with the increase of the burial depth. The deposit basement of the ore body is mainly Ordovician Fengfeng Formation limestone, and a few are Majiagou Formation and Cambrian Fengshan Formation. The sedimentary cover is thick limestone in the north, interbedded limestone and mudstone in the middle, and thin limestone and mudstone in the south. The exploration and development of bauxite under the coal in Shanxi faces difficulties such as complex ore body shape, straddle goaf, difficult roof maintenance, and complicated hydrological conditions. The survey must first identify the basement structural form of the ore body, the occurrence range of the ore body and the spatial occurrence characteristics and water richness of the upper mined-out area. During the coal mine exploration stage, the scope of the ore body is mainly identified and the favorable metallogenic area is delineated. The engineering geological conditions are mainly identified during the construction and production phases of coal mines. The closed pit coal mine must first find out the range of goaf and water accumulation and gas geological conditions. It is necessary to fully consider hydrogeological conditions and develop roof support at the same time.