Mining of rich iron ore deposits of complex structure under the conditions of rock pressure development

Abstract

The purpose of research is to increase the ore mass extraction ratio when mining rich iron ores by changing the shape of the stope chamber, as well as to substantiate its stable parameters under the conditions of the rock pressure manifestation. Used in mines existing methodologies for determining the structural elements of mining system are based on calculated equivalent spans of outcropping the stope chambers, which have a rectangular or tent shape. For the first time using the ANSYS software package, it has been determined that the formation of a compensation chamber of quasi-parabolic shape can significantly reduce the stresses concentration around the stope block. Thus, the formation of a stope chamber of a quasi-parabolic shape makes it possible to reduce vertical stresses as compared to horizontal ones without increasing horizontal pressure. When mining the extraction block, it is proposed to form the stope chamber of a quasi-parabolic shape with geometric parameters that directly depend on the parameters of the deposit, the depth of mining, and the direction of main stresses action. Dependences have been determined of the stresses value on the depth of mining and the physical properties of rocks, as well as on the length along the strike of the ore deposit. Thus, depending on the mining depth and length along the strike, rock pressure on the stope chamber of a quasi-parabolic shape decreases under non-uniform loading. The formation of a stope chamber of a quasi-parabolic shape will increase by 1.2 – 1.5 times the volume of pure ore that is recovered from the block.

Innovative mining technologies with complex geomechanical characteristics

“…Similar systems have been also described for the development of complexstructured rich iron deposits. [3] It is important to define correctly the parameters of blasting works, taking into consideration the strain and stress condition of the rock mass when applying these systems for development. [4]…”

Efficiency of application of fiber concrete as a material for manufacturing bodies of centrifugal pumps

“…Currently, fiber-reinforced concretes are widely used in the production of building materials and have been thoroughly investigated. However, there are practically no works related to the study of the use of these materials in mechanical engineering, especially for the manufacture of parts of technological equipment [8][9][10].…”

Determination of the parameters of local reinforced zones under the protection means

“…In Ukraine most of the resources are extracted with the underground method in conditions of high mining pressure. For ore deposits the main problem is efficient crushing of strong rocks [4] and ensuring the stability of workings and chambers at depths of 1115-1900 m [5][6][7], whereas in coal mines the situation is more complicated due to soft adjoining rocks, water content, disturbance of coal seams, and so on. The negative impact of these factors affects the general condition of the mine workings at depths of more than 300 m, especially preparatory ones, which are additionally exposed to actual works.…”