Abstract
Aimed at the problem to plug the main ore pass with the large collapse at Xingshan Iron Mine, the viscosity-time test and the heap perfusion test of cement-silicate grout in a loose rock mass are carried out. The relationship between the vertical diffusion distance of cement-silicate grout and setting time of grout is studied, and research results are applied to the design of plugging engineering of the main ore pass in -330 m. Based on the numerical simulation of the plugging structure and the long-term stress monitoring of the cable sensors, the stability of the plugging structure itself and the control for the movement of shafts nearby are comprehensively evaluated. The test results show that for a specific loose rock mass, the vertical diffusion distance of cement-silicate grout in the loose rock mass is a power function of grout setting time. Based on the design concept to plug the main ore pass with the large collapse using artificially constructed “bite-bonded arch,” the plugging design and construction procedures are proposed. A numerical model and long-term monitoring of cable stress show that the plugging structure is stable and has an obvious effect on the control movement of abutment shafts.
Highlights
The main ore pass as an important passage for ore transfer is critical to maintaining normal production of all mines
In order to answer the above three key questions, the analysis is based on design ideas and technical measurements are decomposed step by step as follows: (a) The plugging mode of the ore pass is inspired by the phenomenon of overhanging arches frequently occurring in ore passes [2, 3], and the occlusal arch and cohesive arch in the overhang arch are fully combined to form a stable plugging structure by constructing a “bite-bonded arch,” which is formed by methods of grouting and installing a cross steel body in the loose rock mass, as shown in Figure 2 (b) Based on the characteristics of large voids in the loose rock mass, it is difficult to control the diffusion range of cement grout in the loose rock mass
Combined with the specific engineering needs that vertical flow of cementsilicate grout cannot block the lower section of the ore pass, in view of practical technology, it is assumed that the onedimensional vertical diffusion distance of cement-silicate grout with different setting times in the specific loose rock mass is expressed as a function only related to the setting time
Summary
The main ore pass as an important passage for ore transfer is critical to maintaining normal production of all mines. And internationally, there are few studies on the large collapse of the main ore pass, mainly focusing on the mechanism and countermeasures of the overhanging arch [2, 3], the stability analysis of the ore pass, and the grouting reinforcement [1, 4]. Aimed at the problem to plug the main ore pass with the large collapse at Xingshan Iron Mine, the viscosity-time test of cement-silicate grout and the heap perfusion test of cement-silicate grout in a loose rock mass are carried out. The relationship between the vertical diffusion distance of cement-silicate grout and the setting time of grout is studied, and the research results are applied to the design of the plugging engineering of the main ore pass in -330 m at Xingshan Iron Mine. Based on the numerical simulation of the plugging structure and the long-term stress monitoring of the cable sensors, the stability of the plugging structure itself and the effect for the movement of the main shaft and auxiliary shaft nearby are comprehensively evaluated
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