The caving of thick and strong roof stratum causes tremendous rock pressure in mine.The results of the analysis on dynamic natures of actual measurements of some fields,of which the roof pressure can be caused by thic...The caving of thick and strong roof stratum causes tremendous rock pressure in mine.The results of the analysis on dynamic natures of actual measurements of some fields,of which the roof pressure can be caused by thick and strong stratum in long wall thick coal caving face,could present the relation between the collapse and movement of thick and strong roof strata and surrounding rock pressure.In order to control the roof pressure effectively,the thick and strong roof strata,can be fractured and softened previ- ously by hydraulic fracturing and low-high pressure water infusion,fracturing and softening method.The results of study can provide basis for strata control and safe management in long wall thick coal caving face.展开更多
Higher production, better safety standard, and potential for automation are some of the benefits of longwall mining. Today, longwall face advances at a faster rate exposing many diversified rock layers in a short peri...Higher production, better safety standard, and potential for automation are some of the benefits of longwall mining. Today, longwall face advances at a faster rate exposing many diversified rock layers in a short period of time. It is now a serious challenge to cope with ground control problems such as roof falls, face and floor failure, and excessive shield loading as fast as possible to minimize production and monetary losses. In Illinois Coal Mines, the existence of weak floor strata blow the coal seam may pose additional problems related to floor heaving, shield base punching, and associated roof and face falls. In this study, the effects of weak floor on longwall ground control are analyzed using two dimensional finite element models. A two leg 635 6 ton (700 short ton) yielding capacity shield is included in the models to evaluate the effects of different thickness and material properties of the weak floor. The study indicates that the thickness and material properties of weak floor have significant effects on shield loading, the distribution and intensity of front abutment stress, failure zones in the surrounding strata, roof to floor convergence, and floor punching by the shield base.展开更多
文摘The caving of thick and strong roof stratum causes tremendous rock pressure in mine.The results of the analysis on dynamic natures of actual measurements of some fields,of which the roof pressure can be caused by thick and strong stratum in long wall thick coal caving face,could present the relation between the collapse and movement of thick and strong roof strata and surrounding rock pressure.In order to control the roof pressure effectively,the thick and strong roof strata,can be fractured and softened previ- ously by hydraulic fracturing and low-high pressure water infusion,fracturing and softening method.The results of study can provide basis for strata control and safe management in long wall thick coal caving face.
文摘Higher production, better safety standard, and potential for automation are some of the benefits of longwall mining. Today, longwall face advances at a faster rate exposing many diversified rock layers in a short period of time. It is now a serious challenge to cope with ground control problems such as roof falls, face and floor failure, and excessive shield loading as fast as possible to minimize production and monetary losses. In Illinois Coal Mines, the existence of weak floor strata blow the coal seam may pose additional problems related to floor heaving, shield base punching, and associated roof and face falls. In this study, the effects of weak floor on longwall ground control are analyzed using two dimensional finite element models. A two leg 635 6 ton (700 short ton) yielding capacity shield is included in the models to evaluate the effects of different thickness and material properties of the weak floor. The study indicates that the thickness and material properties of weak floor have significant effects on shield loading, the distribution and intensity of front abutment stress, failure zones in the surrounding strata, roof to floor convergence, and floor punching by the shield base.
