Analysis Of Mechanical Properties And Study About Comprhensive Classfying Of The Stability Of The Deep Rock Mass Of Xinqiao Mine

Tongling Chemical Industry Group Xinqiao Mining Company (Xinqiao Mine) is a large copper-sulfur based mine with the exploration of strip mining and underground mining.The main producting stage has deepened to -270m and -300m with Flat-backcut and fill stoping method in two steps.The activities of earth pressure would be more ferquent as the mining depth goes deeper. What's more, Sublevel -180m～-230m has no permanent continuous panel pillar and the 0.15～0.20 k m2 large mined-out area was filled poorly(low strength, poor integrity,high degree of unsuppoted roof) with river sand filling(first filling step) and Non cemented filling(second filling step), which makes the conition of deep mining worse when stoping, especially in the second step extracting chambers, there are often accidents such as rib spalling and local caving.To ensure the safety of mining in -270m and make a basis for the design of deep mining(under -300m), overall investigation, anlysis, measuration and research must be done as well as getting reliable rating standard of rock mass stability and safe operating and managing well tageted.This assay shows the industry conditon of deep mining by exausting geology survey of -270m, including deep mine(-270m) stope organization, extractiong engineering, geology conditon(rock quality of top and bottom, stability, RQD indicator), destroying of projects(fault, fissuring, cranny), hydrological geology. On the basis of the statistical analysis of investigation, geomechanic parameters of local samples are measured indoor, involving main physical properties(compressive strength, tensile strength, angle of intenal friction, elastic modulus, Cohesive force and Poisson ratio), and rock mechanicas is reduced as engineering rock mechanics by Hoek-Brown failure criterion.Classifying preliminarily the stability of deep rock masses by Q system, RMR and BQ, integrating results of numerical analysis and fussy comprehensive evaluation, comprehensive classfying of the stability of ore and rock in-270 is finally complished.Results of the classifying are certified by the real mine producting, which basically fit the stable condition of rock masses in-270m and they have successfuly guided production practice and provided data for the activity rules and control of earth pressure in deep rock masses.As a result, this research is much important and essencial to realize the lasting, safe and fast development of Xinqiao Mine.