Study On Stability Analysis And Treatment Technology Of Old Mined - Out Area Of ​​Wuxian Tungsten Tin Mine In Lushui County Of Nujiang Prefecture

In recent years, faced with goaf which is formed during underground mining, because of the stability of goaf, some mine safety accidents occur from time to time caused by roof caving, wall caving, air shock wave, surface subsidence and so on. Therefore, it is essential to evaluate the stability of goaf and make technology program. To prevent mine personnel, equipment, production hazard caused by goaf stability.This paper takes a untreated old goaf formed by V401 ore body in Wuchashu, Lushui, Nujiangzhou as engineering background, and master overburden failure mechanism, the theory of "three zones" and "air shock wave" formation process. Thus calculated risk crack zone height and air shock wave velocity. At last, this paper simulates the safety stability of the goaf by FLAC3D. Hope for this can provide scientific reference for reasonable and economic governance goaf. The main research contents are as follows:(1) Collect related information in mine. Get down the mine to understand the present situation of the mined-out area, the situation of mining and mining process and so on.(2) Refer to related references about goaf governance, and understand the domestic and foreign research status and the management method.(3) The study found that the traditional formula of breaking belt with a certain scope. If applied the formula to the steeply inclined ore body, we need to modify the traditional formula and change some factors in the formula.(4) Then analyze the harm of air shock wave and the formation process. Based on shock wave physical model, this paper calculates the biggest air shock wave velocity of the ore body’s old mined-out area, we find shock wave speed is 37.14 m/s which is produced by the wide range and continuous caving. The speed human body can withstand is 12 m/s～15 m/s, so 37.14 m/s is more than the scope.(5) Use FLAC3D to establish ore body model, then analyze the safety and stability of goaf, these can provide some reference for governing goaf.(6) According to the result of simulation analysis, we decided to set the closed wall and filling method to govern goaf. And then use software once again to simulate and analyze effect after governance. The results show that after the governance, the goaf is in the safe and stable state.