The paper gets every sublevel recovery index of diversity structure parameter through multitude sublevel drawing experiment in the condition of diversity drift interval and drawing pace.

A 3dimensional model experiment was therefore carried out in lab with the intention of determining such constructional parameters as drift intervals and drawing pace to meet the mining requirements after the sublevel height has been up to 125?m.

Combined with the Xishimen Iron Mine sublevel caving mining situation and the drawing simulation experiment,this paper analyzed the rock and ore moving process in drawing and caving,dexcribed the relationship between the drawing pace and mixed rock amount.

Pillarless sublevel caving is adopted by Dahongshan Iron Mine in the underground minin stope with the capacity of 4 million t/ a and its ore loss and dilution not only relate with the structural parameters of the mining stope,the independent advance of ore breaking,but also blasting parameters of the drilling directly impact on development status of ore drawing off.

The effects of different drawing intervaland top-coal fragmental size on flow character of coal-gangue and sand,and on mixed degree of coal and gangue were analyzed during drawing top-coal.

Feasible drawing interval is the basis to study mining equipment of fully-mechanize coal mining with caving method.

Through observing on spot in compound mining face,the activity rule of roof coal is analyzed,the reason of roof coal crushing and distribution state are summrised,the reasonable drawing interval and questions noticed in roof and floor mannge are provided.

A formula for calculating the sublevel caving step_distance is given.

The ore-drawing courses under different ore-drawing-hole spacing are studied with computer simulation.