-
Date submitted2023-06-01
-
Date accepted2024-03-05
-
Date published2024-08-26
Analyzing friction bolts load bearing capacity in varying rock masses: an experimental study in Anti Atlas Imiter silver mining region, Morocco
This study analyzes how key factors impact friction rock bolt capacity using standard pull-out tests, focusing on 39 mm diameter, 180 cm long split-tube bolts. We investigate bolt performance dependence on rock mass rating (RMR), time after installation, schistosity orientation, surface roughness, and installation quality. The aim is optimizing bolt design and implementation for enhanced underground stability and safety. Results show RMR strongly exponentially correlates with pull-out resistance; higher quality rock masses increase capacity. Anchorage capacity significantly rises over time, especially for RMR above 70. Increasing angle between bolt axis and rock foliation from 0 to 90° boosts pull-out response. Reducing borehole diameter below bolt diameter grows bolt-ground friction. Empirical models estimate load capacity based on RMR, time, orientation, diameter, roughness and installation quality. These reliably predict bolt performance from site conditions, significantly improving on basic RMR methods. Experiments provide practical friction bolt behavior insights for typical rock masses. The data-driven analysis ensures models are applicable to actual underground scenarios. This enables tailored optimization of bolting configurations and supports. Methodologies presented should improve safety, efficiency and cost-effectiveness of reinforced mining and tunneling. Overall, this study fundamentally furthers friction bolt performance understanding, enabling superior underground support design.
-
Date submitted2017-11-22
-
Date accepted2018-01-04
-
Date published2018-04-24
Justification of a methodical approach of aerologic evaluation of methane hazard in development workings at mines of Vietnam
- Authors:
- V. V. Smirnyakov
- Nguen Min' Fen
The methods of evaluation of the aerological conditions to be performed for the purpose of normalization of mining conditions are provided in the present review; the location of possible accumulations of explosive gases during the drift of the development workings are taken into account. To increase the safety of the development working regarding the gas factor, a complex evaluation of a working was developed with respect to the dynamics of methane emission and air coursing along the working which is strongly affected by the character of the leakages from the ventilation ducting. Thereby, there occurs a necessity of the enhancement of a methodical approach of calculation of ventilation of a working which consists in taking into consideration a total aerodynamic resistance of the booster fan including the local resistances of the zones of the working. An integer simulation of the gas-air flows realized on the basis of a software package FLowVision allows to evaluate a change in the methane concentration in the zones of local accumulations.
-
Date submitted2014-11-01
-
Date accepted2015-01-18
-
Date published2015-10-26
On the design features of underground multiple gassy coal seam mining
- Authors:
- O. I. Kazanin
The analysis of the industry regulatory requirements and the world design experience of underground multiple coal seam mining is provided. The main problems of intensive longwall mining of multiple flat gassy coal seams as well as methods for determination of high rock pressure zone parameters and seams interaction are considered. The examples of a number of mines in the Kuzbass and Pechora coal basins show that the design of multiple seam mining and the choice of longwall panel parameters were often made without taking into consideration influence of surrounded seams that leads to essential complication of conditions for mining operations and decreases the technical and economic indicators of mining. The existing industry regulations do not allow considering complex influence of factors in multiple coal seams mining fully. On the basis of field, laboratory, and numeric research results it is noted that recommendations for pillar positioning in contiguous seams ensuring efficiency and safety of multiple seam longwall mining can significantly differ in case of liability of coal seams to spontaneous combustion, high natural gas content, influence of multiple seam mining onto daily surface, and difficult conditions of entries maintenance. The importance of having information on the stress-strain condition of the rock mass at a design stage and its changes in the process of multiple seam mining is shown. The need for industry regulations updating for the purpose of a more detailed definition of a form, size and a location of high rock pressure zones as well as stress parameters in these zones is noted. A set of recommendations for effective and safe multiple seam mining is developed.
-
Date submitted2009-10-18
-
Date accepted2009-12-17
-
Date published2010-09-22
Reuse of development workings as an element of providing the effective coal output
- Authors:
- M. A. Ilyashov
The article contains the results of application in a coal mine of a combined way for protection and support of development workings. This method combines a frame support, anchors and a cast support strip erected behind the longwale. The geomechanical substantiation of technological parameters, regulations and the field for efficient use of this method are given. Its introduction has allowed to increase the loads on longwale and to lower labour content and expenses for maintenance of butt entries.
-
Date submitted2009-09-07
-
Date accepted2009-11-17
-
Date published2010-06-25
The transformation of zone of potentially dangerous accumulative wrecks in a layeked mining roof when combined effect of the rock pressure and shock stress waves
- Authors:
- V. V. Karpenko
The transformation of potentially dangerous zone of wrecks accumulation in the layeredroof of the mining system is considered, in the time of combined action of geostatic pressure and tension shok wave. The explosion wave front is suggested to be parallel to the proximate handing roof environs discontinuity. Under this condition in the article is considered the influence of levels of critical stress and the depth of opening location on the change of implicitly dangerous zone of faults accumulation in the layers of the root stone.
-
Date submitted2009-09-06
-
Date accepted2009-11-14
-
Date published2010-06-25
The estimation of mass velocities in a layered roof and dividing pillars of the mining system in the time of influence of shock stress waves
- Authors:
- V. V. Karpenko
- G. A. Kolton
The mass velocity diagrams transformation in the layered border zone of the mining system in the time of tension explosion waves influence is considered. The explosion wave front is suggested to be parallel to the proximate handing roof environs discontinuity. Under the admitted assumption the mass velocity epures transformation is investigated in the layered roof stone of the mining system and in the dividing pillar.
-
Date submitted2009-07-25
-
Date accepted2009-09-09
-
Date published2010-04-22
The use of data on stress-strain state of rock mass in solutions of mining-and-technical tasks on the example of the Tishin ore mine
The Permion State Technical University and ASE «VNIItsvetmet» have carried out in situ measurements of stress-strain state at the Tishinsky lead-zinc ore deposit. Measurements and interpretation of deformations and stresses caused by excavation were used. Complex of researches made it possible to solve some important problems for safeguarding effective and secure ore production ore on deep level.
-
Date submitted2009-07-29
-
Date accepted2009-09-15
-
Date published2010-04-22
Preconditions for application of supports of different types in productive workings of low-thick gently-pitching deposits in tectonically stressed massif (for conditions of the Karnasurt ore mine)
- Authors:
- A. V. Lovchikov
- A. V. Matytsyn
The paper presents the data on the mining-geological conditions for mining and types of stope supports applied at the Karnasurt Mine, the Lovozersky rare-metal deposit. The peculiar feature of mining conditions is the presence of high subhorizontal tectonic stresses in the rock masses, which make the stope roofs more stable, allowing application of non-reinforced types of support.