RESEARCH AND DEVELOPMENT OF ESSENNTIAL TECHNIQUES FOR MINING DEEPLY BURIED AND HIGHLY STRESSED ORES IN JINCHUAN MINING SITE

Jinchuan mining site is the only site for large-scale production of the nonferrous ores in China.It is a site with adverse conditions such as deep depth,high in-situ stress and highly crushed rocks.The mining is there extremely difficult.As the mining depth increases and the mining area expands,the in-situ stresses of the stope has become more and more severe.Therefore,it is urging to disclose and examine the conditions of the in-situ insitu stresses and the corresponding techniques for the large stopes.The mining started 30 years ago.Since then,a large amount of engineering experience have been accumulated for solving the problems.As a result,the first-stage construction of the mines has been implemented without much problem.However,with the development of second-stage construction,especially when level pillars of multi section mining are becoming thinner,the activity of the ground pressure of stopes are much severe,the deformation of tunnels is too large to be controlled,and the potential risk of stop failures isevident.This paper presenta a review of the behavior of the ground pressure and its control techniques in China nd abroad.Next,the problems in the No.1 ore-body of the mining site are described.Finally,the paper presents a dynamic feedback engineering approach to address the problems for safe mining.This approach is based on the integration of numeric analysis,in-situ monitoring and engineering experience.