Research into rock mass geomechanical situation in the zone of stope operations influence at the 10th Anniversary of Kazakhstan’s Independence mine

Abstract

Purpose. Predicting the stress-strain state (SSS) of the rock mass in the zone of stope operations influence using the self-caving mining system and the calculation of the load-bearing capacity of mine workings support at the 10th Anniversary of Kazakhstan’s Independence mine. Methods. An engineering-geological data complex of the host rocks properties has been analyzed. Numerical modelling of the rock mass stress-strain state and the calculation of the load-bearing capacity of the support types used at the mine have been performed with the help of the RS2 software. This program, based on the Finite Element Method in a two-dimensional formulation, makes it possible to take into account a significant number of factors influencing the mass state. The Hoek-Brown model with its distinctive advantage of nonlinearity is used as a model for the mass behaviour. Findings. The values of the main stresses and load on the support have been obtained. According to the numerical analysis results of the rock mass stress-strain state at a depth of 900 m (horizon -480 m), the principal stresses are close to hydrosta-tic ones σ1 = σ2 = σz = 24.8 MPa. Predicting assessment of mine workings stability margin is performed before and after stope operations. Based on its results, it can be assumed that the stability margin of the mine workings driven in the stope zone is below the minimum permissible, therefore, caving and an increase in the load on the support are possible. Abutment pressure on mine workings support at a mining depth of 900 m (-480 m) has been calculated. The parameters of support in mine workings driven at the horizon -480 m have been calculated. Originality.The nature and peculiarities of patterns of the stress-strain state formation within the boundaries of various stope operations influence in blocks 20-28 at the horizon -480 m have been determined. The quantitative assessment of the values of loads on the support of haulage cross-cuts of the horizon mining is given. Practical implications. The research results can be used for creating a geomechanical model of the field and to design stable parameters of mine workings support. Keywords: stress-strain state, principal stresses, support, mine, ore, rock mass

Technological conditions for ensuring the stability of the array of enclosing rocks during the fastening of mine workings

“…and Figure 5 shows the dependences of fracture modulus (L, pcs./m) on the layer thickness (h, m) and tensile strength ( Rр , 2 см кН ), fracturing due to the presence of small-amplitude geological disturbances. Determination of the area of initial rock foliation makes it possible to predict the stability and collapsibility of the rocks of the roof and sides of the workings in order to select rational parameters of their conduct established [ [15], [16], [17]]. Figure 4 shows the dependences of rock pressure fracture spacing (l, сm) on the ratio of geostatic pressure (γН, t/m 2 ) to the compressive strength of rocks ( Rсс , The obtained results on foliation of rocks allowed to create an effective method for fixing the mine workings taking into account the technological foliation of coal-rock massifs with the use of anchor fixing technology.…”

Reduction of ore dilution when mining low-thickness ore bodies by means of artificial maintenance of the mined-out area

“…There are a number of methods that make it possible to conduct in-situ measurements of the rock mass geomechanical parameters. At the same time, in many cases, the validity of the stress values obtained remains an open question due to the incorrect formulation of the inverse problem, in which one or another method finds a theoretical substantiation [44].…”

Substantiating arched support made of composite materials (carbon fiber-reinforced plastic) for mine workings in coal mines

“…Quite large The development of large depths of mining, especially in difficult mining-geological conditions with unstable rocks, requires a reassessment of the requirements for the role of support characteristic. It should be noted that in the studies [24], [25], [26], the maximum permissible stresses are considered to be 100 -150 MPa, which generally corresponds to typical mininggeological conditions and the existing development of means for fastening the mine workings. Under these conditions, the structure is stable, slightly deformed, operates in a yielding mode, and the mine working is able to perform its operational functions.…”