The Analysis of Engineering Geological Condition in Xiaolongtan Lignite Deposit (Yunnan Province, China)

Abstract

The main purpose of this dissertation is to analyse the engineering geological conditions of the Xiaolongtan Lignite Deposit. Through the investigation and analysis to the basic geological condition and 13 disaster-caused factors of the research field, this thesis carries out the engineering geological comprehensive evaluation to the research district, as well as provides the advice and basis for the mining and rehabilitation of deposits in the future. The subjects illustrated in this thesis include the introduction of research field (study 1), review of research background (study 2), introduction of basic geological condition (study 3), research of 13 disaster-caused factors (study 4), engineering geological comprehensive evaluation of the area, as well as the mining and rehabilitation advice in the future (study 5). This thesis applies clinometer, total station, GPS tools to monitor the side slope of open-pit and dump, as well as adopts ArcGIS platform to carry out the coverage partition of disaster-caused factors, and engineering geological comprehensive evaluation. This thesis focuses on illustrating 13 disaster-caused factors that lead to the occurrence of engineering geological, hydrological, fire and eco-environment 4 kinds of disaster, including the stability of slopes, potential flood area, water body, spring, aquifer, aquiclude, gully, lignite spontaneous combustion, building, dump, quarry, road and step. It mainly researches the disaster-caused factor of stability of slopes. According to the research results, there are three slopes in the pit used to though the unstable situation, also the sliding surfaces have been generated that are mainly distributed between the main lignite seam (N1-2x3) and carbon-rich clay stone (N1-2x2). Through the calculation of stability coefficient, except the north slope of Buzhaoba open-pit No.1 is in an unstable state, the other two slopes are in a stable state. According to the engineering geological comprehensive evaluation results, the unsuitable area occupies 18.7% of the total research district, the conditionally suitable area occupies 0.9%, the suitable area occupies 32.7%, and the no disaster area occupies 47.7%. This methodology is applicable to future case studies in an analogous geological structure in combination with a coal quarry.