Application of high-density electrical method to prospect coal fire: taking Huojitu coal mine as an example

China is a large coal-producing country,which consumes a large amount of coal resources every year.Due to the existence of many small coal kilns with backward mining methods,a large number of worked out area have been formed.The abandoned coal mine with no cares,air penetrated into the roadway and contacted with coal seam,as result the residual coal seams were spontaneously ignited to form coal fire.Coal fires not only cause the loss of valuable coal resources,but also cause environmental problems such as ground cracks,collapse,and air pollution,ultimately endangering human safety.The prerequisite for coal fire environmental management is coal fire exploration.Therefore,accurate detection of the distribution range and depth of coal fire is the main problem of coal fire exploration technology and the basis of coal fire extinguishing engineering.This paper taking the Huojitu coal mine as an example,which in Shenmu city,Shaanxi province,thermal infrared remote sensing technology is very effective in detecting coal fires on or near the surface,but it is difficult to identify deep underground coal fires.Then the high-density electrical method is used to detect the underground goaf and fire area,the collected data processed to obtain a resistivity cross-section,and high-medium-low-resistance anomalous sections are identified.With analysis and interpretation correspond to each coal seam floor in the mining area,a large number of goaf and a small number of fired areas are identified.Finally,a few drilling holes proving that the high-density electrical method is very effective in detecting goafs,providing a certain technical guarantee for the later fire-extinguishing projects.