-
Date submitted2021-05-08
-
Date accepted2022-07-21
-
Date published2023-12-25
Technologies of intensive development of potash seams by longwall faces at great depths: current problems, areas of improvement
- Authors:
- Vladimir P. Zubov
- Denis G. Sokol
The results of the analysis of practical experience in the development of potash seams using longwall mining systems at the mines of OAO “Belaruskali” are presented. Positive changes in the technical and economic indicators of mines and an increase in the safety of mining operations were noted with the introduction of resource-saving technologies without leaving the pillars between the excavation columns or with leaving the pillars between the columns with dimensions at which they are destroyed by mining pressure in the goaf. It is noted that the use of mechanized stoping complexes characterized by high energy capacity, combined with large depths of development, is the main reason for the temperature increase in longwalls to values exceeding the maximum permissible air temperature regulated by sanitary standards. Based on production studies, it was concluded that the temperature regime along the length of the longwall face is determined by the temperature of rocks in the developed longwall space, heat emissions from the equipment of the power train, and the temperature of the rock mass ahead of the longwall. The conclusion has been drawn about the feasibility of using developed technological schemes in deep mining conditions, which provide a reduction in longwall temperature by 6-9 °C or more through isolated ventilation of longwall and power trains, as well as heat exchange between the airflow entering the longwall and the rocks in the developed space.
-
Date submitted2021-04-19
-
Date accepted2022-05-25
-
Date published2022-07-13
Development of the technology of stowing the developed space during mining
- Authors:
- Evgenii R. Kovalskii
- Kirill V. Gromtsev
An analysis of the world experience in the development of potash deposits shows that the main problems arising during their development are a high level of mineral losses, an increased risk of flooding of mine workings as a result of water-proof layer discontinuance and the development of emergency water inflows in the mined-out spaces. Reduction of potash ore losses can be achieved by using a long-pillar mining system, but this method is limited by the peculiarities of the geological structure of the potash deposits and the need to preserve the continuity of the water-proof layer during its underworking. The safety of underworking of the water-proof layer can be improved by using the stowing of the developed longwall space. However, the question of the influence of the stowing on the height of the zone of water supply cracks development remains little-studied. The world experience of stowing the developed spaces in the development of layers with long pillars is analyzed and the technology of placing the stowing masses, which can solve these problems, is proposed. The considered technology and the proposed solutions are supported by laboratory tests of stowing materials and mathematical modeling of deformation zones in the overlying rocks.
-
Date submitted2020-05-08
-
Date accepted2020-06-12
-
Date published2020-12-29
Gas-dynamic roof fall during the potash deposits development
In the development of practically all potash salt deposits, the study of gas-dynamic phenomena (GDP) is one of the most difficult tasks to ensure mining safety. Sudden salt and gas outbursts, dynamic breakdown, which are accompanied by intense gas release and possible broken rock carry-over into the mine workings, are associated with GDP. Geological preconditions for the GDP development are often the layered structure of the salt rock mass, the presence of interlayers and layers of salt clays. For the conditions of the Usolsky potash plant mine, complex studies of factors that characterize the possibility of gas-dynamic roof fall of the stoping rooms were carried out. In mine studies, free gases pressure and the initial velocity of gas release in the rocks of the roof workings were determined. The obtained experimental estimations were used as a parametric basis for mathematical modeling of geomechanical processes under conditions of a near-contact accumulation of free gas. The deformation of a layered salt mass produced by a room development system was described by the model of an ideal elastic-plastic medium with internal friction. The parabolic envelope of Mohr circles was used as a plasticity criterion in the compression area. In the numerical implementation, the deformation of clay contacts was modeled by Goodman contact elements. Based on the results of multivariate numerical calculations, it is established that the main factors determining the possibility of implementing GDP are the additional gas pressure at the contact, the width of the workingspan, and the distance from the roof to the first gas-containing contact. With multi-level lamination of roof rocks, there is a danger of large sources of GDP formation and the mechanism of successive fall of layers in an instant mode is implemented.
-
Date submitted2019-07-22
-
Date accepted2020-01-04
-
Date published2020-04-24
“Ural-20R” combines loading drives evaluation in two-stage development of the face
The technological features of the use of high-performance Ural-20R combines in the conditions of potash mines in Russia are described. It is shown that when the capacity of the worked potash seams is over 4 m, a two-layer ore extraction is used. The formation of cutting process, implemented by the second course of the combine in the treatment chamber, is carried out by an incomplete section of the executive bodies. The standard control system, display and protection of the Ural-20R combine does not allow monitoring and reliable estimation of the magnitude of dynamic components on the drives of the mining machine loads, as well as tracking the feed rate of the combine to the face. The regulation of the operating parameters and the assessment of the degree of loading of the drives of the excavating machine in real time are assigned to the operator. The fundamentals of the experimental research methodology for assessing the loading of drives of Ural-20R combines with the destruction of the potash mass by an incomplete section of the executive bodies are described. The device and the operating procedure of the “Vatur” software-recording complex, which measures, records and records the electrical parameters of the drive motors of a mining machine, is described. The process studies results of forming loads on drive elements of Ural-20R combines when mining a face with an incomplete section of executive bodies are presented. It is proved that the work of combine harvesters on the undercut of the formation with a high feed rate is accompanied by significant dynamic loads on the drives of planetary organs and an overload of the drives of the Berm organs, which leads to an accelerated consumption of the resource and emergency failures of the gearboxes and motors of the extraction machine.
-
Date submitted2014-11-07
-
Date accepted2015-01-07
-
Date published2015-10-26
The concept of reducing the risks of potash mines flooding caused by groundwater inrush into excavations
- Authors:
- V. P. Zubov
- A. D. Smychnik
Results of the analysis of factors influencing the probability of accidental groundwater inrush into mine workings of salt (potash, potassium and magnesium) mines are given in the article. The cases of the potash mine flooding that occurred in different countries with developed mining industry are given. It is shown that at the present technical and scientific level of solving this problem the unexpected groundwater inrush in potash mines usually results in the shutdown of the enterprise and negative ecological consequences. It is pointed out that the underground waters flow into the mines through water-conducting fractures of either natural or technogenic origin which location and influence on a mine was almost impossible to predict at the design stage under existing regulations. The concept of reducing the risks of potash mine flooding caused by underground waters in-rush is formulated. Administrative and technical measures which allow reducing the risks of potash mine flooding caused by groundwater inrush into the excavations are considered.
-
Date submitted2013-07-18
-
Date accepted2013-09-02
-
Date published2014-03-17
Rock mechanics problems decision algorithm for bottom layers of potash salt deposits
Decision algorithm for rock mechanics problems for bottom layers of potash deposits is suggested. Flow chart for the algorithm and it’s parts is shown. The algorithm represents the method to choose excavation technology for multi-layer potash deposits.
-
Date submitted2013-07-28
-
Date accepted2013-09-27
-
Date published2014-03-17
The analysis of the stress-and-strain state in vicinity of mining excavations
- Authors:
- A. A. Sankovskii
- E. R. Kovalsky
Estimation of the strain-and-stress state and displacement of the waterprotective layers in vicinity of mining excavations in conditions of SKRU-3 mine (Uralkali Group) is done. It is shown that loadings on pillars on layer Kr.II exceed 15-20 % loadings on layer AB.
-
Date submitted2009-08-26
-
Date accepted2009-10-25
-
Date published2010-02-01
The improvement of selective extraction of thick potash seams mined with room and pillar mining method
- Authors:
- Yu. G. Sirenko
- M. Yu. Brychkov
- E. R. Kovalsky
Technological scheme of selective extraction of a complex thick potash seam on the basis of cutting machine «Bucyrus Model 25 M0» is proposed. Stable pillars’ width and room dimensions are calculated. Economical effect is also presented.
-
Date submitted2009-08-01
-
Date accepted2009-10-29
-
Date published2010-02-01
Increase of competitiveness of russian and belorussian potash companies owing to perfection of sale policy
- Authors:
- T. V. Ponomarenko
- A. N. Sultani
The potassium companies of Russia and Belorussia, developing the unique deposits of potassium salts, provide more than 40 % of the world production of potassium fertilizers. Therefore economic efficiency from their activity considerably influences to the world market of potassium. Being the companies which export more than 80 % producible products «Belaruskali», «Uralkali» and «Silvinite» have problems with the transport of fertilizers in Brazil, India, China. Therefore for the increase of competitiveness of these enterprises it is necessary to develop an effective logistic chain which would take into account their geopolitical features.
-
Date submitted2008-11-28
-
Date accepted2009-01-20
-
Date published2009-12-11
Model of evaluation of the mining enterprise’s competitiveness’ potential
- Authors:
- T. V. Ponomarenko
- A. N. Sultani
Competitiveness of a mining enterprise has a dynamic character which defines a necessity to evaluate a potential of competitiveness at the moment and in the future. The evaluation of competitiveness’ potential has to be systematic, to engulf different levels which are differentiated by interval of evaluation, information sources, evaluation base, methods and results. The method of evaluation of basic indices of competitiveness’ potential is presented in this paper. The calculation of operation and dynamic competitiveness’ potential of JSC “Uralkali” and JSC “Silvinit” for 2007 year was made and the interpretation of received results was given.