Study of strip-filling for old room and pillar mining goaf
According to the problems of land resources destruction and environmental pollution caused by the collapse of old room and pillar mining goaf, a goaf security evaluation model was established and applied to the safety assessment of a colliery in Ordos city. The results indicated that the room and pillar mining goafs in this coal mine area would fail with time passing. To solve the problems, with analyzing the structural characteristics and activation mechanism of old room and pillar mining goaf, based on the theory of strip mining, a new method of strip-filling for controlling subsidence of old room and pillar mining goaf was put forward and used in designing of the strip-filling plan of the colliery, the filling effect prediction have been worked out. It demonstrates that the strip-filling method is economically feasible.
Study on the Comprehensive Assessment of the Western Regions Ecological Environment
In recent years,the ecological environment in the western regions of China has been in a severe situation on the whole because of the inherent frangibility of western regions ecological environment on the one hand,and the man-made,economic,political and legal factors on the other hand.Therefore,the western region would shoulder double duties of environmental protection and economic development.Faced with the double tasks,the western region should adopt interactive model of development and establish the index system of comprehensive assessment on its ecological environment,so as to implement double wins in environmental protection and economic development and improve its ecological environment,at the same time realize the sustainable development of western regions ecological environment,economics as well as society.
In situ strength and deformation characteristics of coal
Abstract This paper contains details ofin situ large scale tests conducted on coal specimens measuring up to 5 × 5 ft. in cross-section and up to 5 ft. in height. Experimental techniques used are described and results of tests aimed at determining the in situ strength and deformation characteristics of coal are given. Stress-strain behaviour of coal is discussed and practical applications of this study to the design of full size coal pillars are dealt with in detail. It is shown that the strength of pillars cannot be expressed by a power function of their width and height as there exists a critical pillar size above which the strength of coal does not change with an increase in pillar dimensions. A new relationship describing the strength of full size coal pillars is presented and its validity verified by experimental data.