Stability Analysis Method to Underground Goafs in Opencast Mining Based on FEM

The 3D model of terrain, which includes goafs, is built by use of terrain generator from MIDAS GTS. The method is developed that the model is stress analyzed by FEM (finite-element method). The following cases are considered: rock weight, loose rock and Heavy Equipment on step surface. Finally, used to the field datum from Luo’yang Molybdenum Co., Ltd., modeling and stress analyzing are finished by the software of MIDAS GTS. The result indicates that the method could provide scientific basis for Safety and Management to open-pit with Underground mined-out area.

Model Test Research of the Influences of Rock-Fall Impaction on Deformation of the Cut-and-Cover Tunnel Structure

On conditions of different weight，height, shape and the property of slope surface, the tunnel portal structure’s deformation evoked by rock-fall impaction has been researched in laboratory by using a 1/30 scale similar model. The study shows that there is a simple linear relationship between the structure’s deformation , the rock weight and the rockfall height when the slope gradient is 1:0.5 and the slope surface is slippery and the multiple linear relationship between the structure’s deformation , the rock weight and the rockfall height has been obtained. Effect of the shape of the rockfall and the property of slope surface on structure’s deformation has been comparative analyzed.

Model Test Research of the Influences of Rock-Fall Impaction on Accelerations of the Cut-and-Cover Tunnel Structure

On conditions of different weight and height, the tunnel portal structure’s accelerations evoked by rock-fall impaction have been researched in laboratory by using a 1/30 scale similar model. The study shows that the normal acceleration value is the biggest, the lateral acceleration is second and the longitudinal acceleration is the minimum. There is a simple linear relationship between the structure’s acceleration, the rock weight and the rockfall height when the slope gradient is 1:0.5 and the slope surface is slippery. The multiple linear relationship between the structure’s normal acceleration, the rock weight and the rockfall height has been obtained.

Model Test Investigation of Rock-Fall Impaction to Cut-and-Cover Tunnel Arch Structure

On conditions of different weight，height, shape, slope gradient and the property of slope surface, the tunnel portal structure’s strain evoked by rock-fall impaction has been researched in laboratory by using a 1/30 scale similar model. The study shows that there is a simple linear relationship between the structure’s strain , the rock weight and the rockfall height when the slope gradient is specific and the slope surface is slippery and the multiple linear relationship between the structure’s strain , the rock weight and the rockfall height has been obtained. Effect of the shape of the rockfall and the property of slope surface on structure’s strain has been analyzed; The distribution characteristics of the structure’s strain of different parts of one cross-section and the same parts of different cross-sections has been comparative analyed.

Rock Remover Design for an Amadas Combine1

Peanuts are harvested with various amounts and types of foreign materials that must be removed during post-harvest processing for consumer acceptance of peanut products. To assist in rock removal during harvest, a modification to the pneumatic conveyor system used to transport peanuts from underneath a standard Amadas combine to the holding bin was designed. The design utilizes air flow patterns and cavitations following an elbow in the duct system and consists of a properly sized and spaced opening in one component of the conveyor system. A stationary pneumatic conveyor system with a controllable peanut delivery apparatus was utilized in developing the duct modification. After preliminary testing during development, the efficiency of the duct modification rock removal was evaluated with three lots of peanuts averaging 0.45 t containing an average 371 rocks (3.2% of sample mass). Peanuts were conveyed through the duct system at an average flow rate of 3.9 t/hr. An average of 30 rocks comprising 42.5% of the total rock weight was extracted from the peanuts. The weight of rocks removed averaged 153.5 g and ranged from 18.7 to 320.7 g. Rocks not removed averaged 24.2 g and ranged from 1.7 to 202.8 g. Results from the tests indicate that the design of the duct modification appears to be effective in removing larger rocks from peanuts but not effective in removing smaller rocks.