The Detection Research To Goaf Of Open Pit Iron Mine In Anqian

In the Anqian open-pit iron mine,the former the unknown goaves due to reasons such as early illegal mining casually have brought great potential safety hazard to mine production.Whatever it has good economic benefit and social benefit to study goaves,make evaluation of them,point out the position of the goaves and puts forward appropriate measures to prevent and control by quickly exploration geophysics method effectively and economicly.This paper,starting from the basic characteristics of iron ore goaves,study on the detection of the mine goaves by using seismic image method,high density resistivity method and transient electromagnetic method.We analyzed the basic principle of seismic image method and the selection of optimal offset,discussed the the field electrode layout of high density resistivity method,indoor data processing,rejection of bad points,direct and inversed evolution calculation and modeling,etc.We also carried out the simulation experiment study on the high-density resistivity method,simulated the different goaves respectively,and discussed the anomaly characteristics of the superposition of all kinds of empty area.Based the basic principle of transient electromagnetic method,the device of transient electromagnetic method was summarized,and the basic characteristics of transient electromagnetic field,the data acquisition and processing of transient electromagnetic method was expounded,mainly including filtering processing,topographic influence and correct,positive inversion calculation and test analysis.Finally combining with engineering example,the section profiles of the high density resistivity method,seismic prospecting method and transient electromagnetic method was obtained,and we detected iron ore goaves to guide future mining development plan execution,and provide the reference for the prevention of geological disasters.Based on the analysis of principles of the seismic image method,high density resistivity method and the analysis of the transient electromagnetic method,this paper introduced the work processes of three geophysical field methods,and then we carried on the test.Finally,combining with engineering living example,we carried on the thorough analysis and the preliminary discussion for the area of goaf detection applications of three geophysical prospecting methods.The following conclusions:1?Based on the analysis of living examples,seismic image method has a optimal offset,the choice of optimal offset needs the change of shot-geophone distance,and the size of optimal offset is connected with the burial depth of the mined-out area,shape,the surrounding rock properties and other factors.The determination of the optimal offset provides a lot of convenience for the search of goaves.2?Seismic image method,high density resistivity method is applicable to the shallow cavity detection,and transient electromagnetic method is suitable for medium and deep cavity detection.3?The electric field distribution has different characteristics under different geological conditions with different types of goaves.Under complicated geological conditions with the exist of surrounding rock and stone,the detection results of each device in empty area affected by different degree,in which distortion of dipole device is larger and the influence of wenner is less.4?For high density resistivity method,the condition to distinguish horizontal stacking empty area is that adjacent empty interval distance is greater than or equal to the width and depth of the goaf.It is generally not appropriate to be distinguished for vertical stacking empty area.5?Model test results of transient electromagnetic method showed that there is a problem of reasonable choosing the number of coil turns in the experiment work.It is inapposite with an excess number of coil turns for shallow detecting.For deep detecting,we can increase the number of launch turns,but only if the electromagnetic oscillation of observation signal which needs to test in the practical work did not occurred.6?Through a lot of field work and indoor summary,we put forward the suitable comprehensive geophysical prospecting method and analysis of anomaly interpretation method for the detection of the goaves in the Anqian open-pit iron mine,which provides the theoretical and practical basis for the next goaves detection of this field and offers the reference for the goaf detection of other areas.