Unit weight patterns of overlying rocks above commercial-value salt strata in the Upper Kama deposit

2021 ◽  
pp. 39-45
Author(s):  
D. S. Chernopazov ◽  
D. N. Shkuratskiy ◽  
A. I. Sekuntsov
Keyword(s):  
Damage Zone ◽  
Shear Plane ◽  
Plane Elasticity ◽  
Unit Weight ◽  
Mining Operations ◽  
Support Design ◽  
Salt Rocks ◽  
Main Requirement ◽  
Potash Salt ◽  
Coulomb Criterion

Stability of rocks is the main requirement for the safe operation of mines. For this purpose, certain measures are applied for the protection and support of underground openings, including roof support design and roof arrangement in the most stable rocks. Stability assessment of underground excavations is largely related to their roof stability. Determination of possible instability conditions in mine roofs governs the choice of support system design and parameters of mine excavations. The Upper Kama Potash Salt Deposit represents a stratified layer of solid salt rocks. Roof instability develops as stratification and roof collapse. The Mohr–Coulomb criterion of coherent rocks is currently used to estimate parameters of a possible damage zone in the exposed roof. This criterion allows evaluating shear plane angles in roof rocks and, as a result, finding parameters of the possible collapse zone. The experience of mining operations in the Upper Kama deposit shows different failure conditions as against the Mohr–Coulomb criterion as the stress state is scarcely included in the criterion used. This study is an attempt to assess parameters of rock exposures by solving a Lame problem in terms of a single mine excavation. The analytical results were compared with the parameters obtained from the plane elasticity solutions by the finite element method. Based on the implemented studies, an engineering approach is developed for the assessment of anticipated instability parameters in exposed roofs in horizontal excavations driven in salt rocks.

Assessment of instability initiation in exposed salt rock roofs

2021 ◽  
pp. 34-38
Author(s):  
D. N. Shkuratskiy ◽  
D. S. Chernopazov ◽  
I. B. Vaulina
Keyword(s):  
Damage Zone ◽  
Shear Plane ◽  
Plane Elasticity ◽  
Mining Operations ◽  
Support Design ◽  
Salt Rocks ◽  
Main Requirement ◽  
Potash Salt ◽  
Failure Conditions ◽  
Coulomb Criterion

Stability of rocks is the main requirement for the safe operation of mines. For this purpose, certain measures are applied for the protection and support of underground openings, including roof support design and roof arrangement in the most stable rocks. Stability assessment of underground excavations is largely related to their roof stability. Determination of possible instability conditions in mine roofs governs the choice of support system design and parameters of mine excavations. The Upper Kama Potash Salt Deposit represents a stratified layer of solid salt rocks. Roof instability develops as stratification and roof collapse. The Mohr–Coulomb criterion of coherent rocks is currently used to estimate parameters of a possible damage zone in the exposed roof. This criterion allows evaluating shear plane angles in roof rocks and, as a result, finding parameters of the possible collapse zone. The experience of mining operations in the Upper Kama deposit shows different failure conditions as against the Mohr–Coulomb criterion as the stress state is scarcely included in the criterion used. This study is an attempt to assess parameters of rock exposures by solving a Lame problem in terms of a single mine excavation. The analytical results were compared with the parameters obtained from the plane elasticity solutions by the finite element method. Based on the implemented studies, an engineering approach is developed for the assessment of anticipated instability parameters in exposed roofs in horizontal excavations driven in salt rocks.

scholarly journals A New Strain-Softening Constitutive Model for Circular Opening considering Plastic Bearing Behavior and Its Engineering Application

2018 ◽  
Vol 2018 ◽  
pp. 1-13
Author(s):  
Liang Chen ◽  
Xianbiao Mao ◽  
Ming Li ◽  
Wei Zhou
Keyword(s):  
Strain Softening ◽  
Damage Zone ◽  
Peak Load ◽  
Surface Displacement ◽  
Circular Opening ◽  
Tunnel Wall ◽  
Support Design ◽  
Plastic Model ◽  
Research Results ◽  
Bearing Behavior

Geomaterials generally show strain-softening characteristics after peak-load. Based on the triaxial test for sandy mudstone, a simple elastopeak plastic-strain-softening-damage model (EPSDM) was proposed. Compared with the traditional strain-softening model, EPSDM shows obvious plastic bearing characteristics before strain softening. Then, the closed-formed solution of circular opening was deduced based on the newly proposed model. A plastic shear strain increment was introduced as the extension constraint condition of peak plastic zone. The solution correctness of EPSDM was also verified by comparing with other research results. In addition, the solution based on EPSDM could degenerate for a series of results obtained by elastobrittle plastic model (EBM), elasto-strain-softening model (ESM), and elasto-perfectly plastic model (EPM) under certain conditions. Hence, it could be regarded as a unified solution. Finally, the research results denoted that when the inner pressure was fully released, the maximum postpeak failure radii and surface displacement of surrounding rock indicated the characteristics of EBM>ESM>EPSDM>EPM. Therefore, the plastic bearing behavior could effectively decrease the postpeak failure zone radii and surface displacement. The dilation coefficient noticeably influenced postpeak failure range and surface displacement, particularly the damage zone radii and tunnel wall convergence. The research results can provide very important theoretical bases for evaluating the tunnel stability and support design reliability for underground engineering.

The creep of potash salt rocks from Saskatchewan

1993 ◽  
Vol 11 (3) ◽  
pp. 159-184 ◽  
Author(s):  
E. J. Scott Duncan ◽  
Emery Z. Lajtai
Keyword(s):  
Salt Rocks ◽  
Potash Salt

scholarly journals Fiber optic control system for geotechnical parameters of mine

2021 ◽  
pp. 64-68
Author(s):  
A. D. Mekhtiyev ◽  
◽  
A. I. Soldatov ◽  
Ye. G. Neshina ◽  
A. D. Alkina ◽  
...  
Keyword(s):  
Rock Pressure ◽  
Fiber Optic ◽  
Hanging Wall ◽  
Testing Methods ◽  
Mining Operations ◽  
Geotechnical Parameters ◽  
Safety Requirements ◽  
Main Requirement ◽  
Fiber Optic System ◽  
Roof Rocks

In the article a fiber-optic method for monitoring rock pressure is considered, as well as the magnitude of the displacement of the layers of the stope hanging wall is measured. The authors analyze the applied rock pressure testing methods. The reasons for the need to create a safe system are given, the main requirement of which is the condition of compliance with all safety requirements during mining operations. The developed quasi-distributed fiber-optic system is capable of measuring with high accuracy changes in rock pressure and displacement of roof rocks in an explosive environment, also does not require expensive equipment associated with the use of a range of analyzers and reflectometers. A scheme has been proposed to simplify the testing process. The results of dependences of additional optical losses on the applied force are obtained

The effect of a nonlinear Mohr–Coulomb criterion on borehole stresses and damage-zone estimate

1994 ◽  
Vol 31 (1) ◽  
pp. 104-109 ◽  
Author(s):  
Yarlong Wang
Keyword(s):  
Oil Sands ◽  
Damage Zone ◽  
Closed Form Solution ◽  
Numerical Approach ◽  
Solution Procedure ◽  
Form Solution ◽  
Far Field ◽  
Circular Opening ◽  
Oil Sand ◽  
Coulomb Criterion

To investigate the possible error introduced by the assumption of a linear Mohr–Coulomb criterion on the stress distribution near a circular opening, a numerical approach is used to calculate both the damage-zone radius and the stresses near a circular opening. A general solution procedure for the stress calculation under a uniform far-field loading is presented and a closed-form solution for the near-opening stresses is given for a cohesionless medium. Based on the numerical results calculated, it is concluded that the linear assumption is acceptable for a strong rock with an unconfined compressive strength that is of similar magnitude to the far-field stress. However, the tangential stress calculated with this linear assumption may be overestimated, but the damage zone may be underestimated in weaker rock or soil such as an oil sand formation. Key words : Mohr–Coulomb criterion, circular opening, nonlinearity, oil sands, Gauss–Legendre method.

DISTRIBUTION OF GASES ALONG THE SECTION OF PRODUCTION STRA TA OF POTASSIUM DEPOSITS

2020 ◽  
Vol 2 (1) ◽  
pp. 271-283
Author(s):  
A.N. ZEMSKOV ◽  
◽  
M.Y. LISKOVA ◽  
Keyword(s):  
Sharp Increase ◽  
Component Composition ◽  
Gas Content ◽  
Gas Migration ◽  
Gas Distribution ◽  
Mining Operations ◽  
Salt Rocks ◽  
Accurate Picture

The problem of changing gas content with depth, in the extension and fall of formations has long been of interest to scientists. The change in the gas content of rocks and the component composition of gases with depth is now becoming more relevant due to the tendency of a sharp increase in the depth of formation of productive formations at new mines and deepening of mining operations at already operating facilities. The article discusses the change in the gas content of salt rocks with depth, peculiarities of gas distribution along the section of the productive thickness ofpotassium deposits, gas migration. Unfortunately, the peculiarities of various mine fields according to the conditions of formation and structure of productive formations, the specificity of mineralogical and morphogenetic composition of rocks do not allow to reveal ranges of depths with preferential detection of certain gases and to give a more accurate picture of their distribution.

Operational control of rib pillar stability

2020 ◽  
pp. 7-10
Author(s):  
A. A. Baryah ◽  
◽  
A. V. Evseev ◽  
I. S. Lomakin ◽  
A. A. Tsayukov ◽  
...  
Keyword(s):  
Rock Mass ◽  
Transverse Deformation ◽  
Russian Science ◽  
Mining Operations ◽  
Pillar Stability ◽  
Room And Pillar Mining ◽  
Salt Mines ◽  
Potash Salt ◽  
Monitoring Procedure ◽  
Mining Safety

In room-and-pillar mineral mining, rib pillars should support overlying rock mass for the specified time limit of production. Therefore, one of the mining safety components is monitoring of the behavior of rib pillars in the course of time. For the conditions of the room-andpillar method of mining, the authors propose a monitoring procedure for rib pillar deformation based on operational measurements of horizontal convergence in stopes. The theoretical and experimental research proves that transverse deformation of rib pillars is an informative parameter suitable for generalized assessment of pillar failure. The obtained ranges of critical transverse deformation rates (50–100 mm/m/yr) in rib pillars can tentatively be used as an indicator of the critical stability of load-bearing structures in room-and-pillar mining. In-situ determination of the integral transverse deformation rates in rib pillars is based on the ratio of the measured horizontal convergence in stopes to the width of pillars. Implementation of the proposed approach in the Upper Kama potash salt mines has proved its applicability to identification of rock mass areas where intense deformation is expected. The comparison of the monitoring data of the transverse deformation rates and their critical values determined makes it possible to predict service life of rib pillars, which is very important in terms of safety of mining operations. This study was supported by the Russian Science Foundation, Grant No. 19-77-30008.

scholarly journals Spatial and Temporal Evolution of Leaching Zones within Potash Seams Reproduced by Reactive Transport Simulations

Water ◽  
2021 ◽  
Vol 13 (2) ◽  
pp. 168
Author(s):  
Svenja Steding ◽  
Thomas Kempka ◽  
Axel Zirkler ◽  
Michael Kühn
Keyword(s):  
Reactive Transport ◽  
Temporal Evolution ◽  
Transport Model ◽  
Significant Risk ◽  
Mining Operations ◽  
Reactive Transport Model ◽  
Potash Salt ◽  
Rock Interface ◽  
Temporal And Spatial ◽  
Hybrid Forms

Leaching zones within potash seams generally represent a significant risk to subsurface mining operations and the construction of technical caverns in salt rocks, but their temporal and spatial formation has been investigated only rudimentarily to date. To the knowledge of the authors, current reactive transport simulation implementations are not capable to address hydraulic-chemical interactions within potash salt. For this reason, a reactive transport model has been developed and complemented by an innovative approach to calculate the interchange of minerals and solution at the water-rock interface. Using this model, a scenario analysis was carried out based on a carnallite-bearing potash seam. The results show that the evolution of leaching zones depends on the mineral composition and dissolution rate of the original salt rock, and that the formation can be classified by the dimensionless parameters of Péclet (Pe) and Damköhler (Da). For Pe > 2 and Da > 1, a funnel-shaped leaching zone is formed, otherwise the dissolution front is planar. Additionally, Da > 1 results in the formation of a sylvinitic zone and a flow barrier. Most scenarios represent hybrid forms of these cases. The simulated shapes and mineralogies are confirmed by literature data and can be used to assess the hazard potential.

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