scholarly journals Diabase from Drača open pit mine in central Serbia - quality assessment for building stone purposes

2021 ◽  
Vol 906 (1) ◽  
pp. 012013
Author(s):  
Ivana Delic-Nikolić ◽  
Lidja Kurešević ◽  
Olivera Vušović

Abstract Vast masses of basic rocks are present as tectonic blocks and slices along the Eastern deep fault of the Vardar zone of Serbia. They are predominantly comprised of gabbro, with smaller part made up of diabase, and occurrences of granite, aplite and pegmatite dykes. Basic rock masses are trending along the line Kragujevac (Ždraljica)-Velika Pčelica-Bogalinac ~8 km west of Rekovac. A significantly smaller diabase massif is present along the same tectonic line, further toward SE, at Prevešt village by Kalenicka River, approximately 13 km south of Rekovac. Drača open pit mine is situated in this diabase massif. Geologic explorative works have confirmed the reserves of 1 846 695 t of stone mass for building purposes. For over a decade, Draca mine has been producing various types of building stone, mainly graded stone aggregate with favourable physico-mechanical properties for road-construction works. Chemical analyses and petrographic study have shown typical composition and fabric for this type of rock. Main constituents are plagioclase and pyroxene, with opaque minerals as accessory and varying secondary minerals – chlorite, calcite, in some places epidote and limonite. Pyrite enrichment is visible in some areas of the massif. Chlorite, calcite, epidote and pyrite are the products of propylitic alteration. Although products of alteration are present throughout the rock mass with variable intensity, as is typical for the basic rocks of the former ocean floor sequences, petrologic properties are favourable for building stone purposes. Physico-mechanical properties of diabase have favourable values and varying scattering degrees. Dry state uniaxial compressive strength average values from seven analyses vary in the range 130-169 MPa. Resistance to abrasion average values vary in the range 9.04-17.07 cm3/50cm2. Apparent density varies within the span 2759-2926 g/cm3 and real density 2804-2951 g/cm3. Water absorption values 0.08-1.04 %. Resistance to weathering through testing of stability using Sodium-sulphate values vary from 0.00 to 0.15 % and through frost resistance from 0.00 to 0.04 %. Porosity values are almost constant at 0.8 %. In more altered parts of the rock mass, porosity reaches 1.6 %. Graded crushed aggregate has favourable values of Los Angeles coefficient 14.2 and 14.3 % for gradation B. Taking into consideration all performed tests and analyses, it is concluded that diabase from Drača mine can be used as a building stone for production of aggregate for use in concrete and for road-construction (asphalt paving mixtures for moderate, light and very light traffic load as a top wearing layer; for lower and upper bearing layers; for classic and modern road foundations); for production of crushed and hewn stone for building; crushed stone for railroad ballast. Also, it can be and is used as a raw material for production of stone wool for thermal insulation purposes.

Author(s):  
Mohammad Ataei ◽  
Reza KaKaie ◽  
Mehdi Ghavidel ◽  
Omid Saeidi

2021 ◽  
pp. 102-106
Author(s):  
O. A. Isyanov ◽  
◽  
D. I. Ilderov ◽  
V. I. Suprun ◽  
S. A. Radchenko ◽  
...  

Instability of pit wall slopes is the most critical accident in open pit mining. The risk of damages to pit walls is proportional to the height of exposed surfaces and to the time of exposure. Among many factors governing pit wall stability, the major factor is geological structure and weakening zones in rock mass. Deformation processes are initiated in host rock mass of coal seams mostly because of undercutting of weak interlayers. Alongside with local undercutting, another cause of landslides is transition of coal mining from down-dip extraction to up-dip extraction. The sequence of mining and morphology of weak interlayers also have influence on initiation and evolution of deformations. The basic component of engineering solutions on pit wall stability control is optimization of mining sequence and methods of accessing working horizons in open pit mines. Large-scale deformation of Western and Southeastern pit walls in Urtui mine could be avoided using the optimized sequence of mining operations. For example, mining advance mostly along the curve of the Urtui centroclinal fold, with early access and destress of the eastern and, first of all, western wings of the fold could make it possible to evade from up-dip mining of coal seams and, as a consequence, to solve the major geomechanical problems in the open pit mine.


Author(s):  
S.V. KOVSHOV ◽  
◽  
A.V. PASYNKOV ◽  

The issues of dust formation and dust suppression in quarries during transportation of rock mass are considered. Foreign and Russian techniques and methods of dust control in open pit mine are analyzed. The limit number of equipment units for the Noyon-Tologoi opencast mine is established, and the dependence of the gross emission of inorganic dust on the number of dump trucks is determined. As a result of a comprehensive analysis, dust suppression methods for a polymetallic open pit mine are proposed.


2021 ◽  
Author(s):  
Tianbai Zhou ◽  
Lingfan Zhang ◽  
Jian Cheng ◽  
Jianming Wang ◽  
Xiaoyu Zhang ◽  
...  

Abstract Due to long-term mining, a series of high and steep rock slopes have been formed in the open-pit mine. For high rock slopes, rainfall infiltration is the main cause of landslide. Therefore, the stability analysis of high rock slope under rainfall has become a key issue in the open-pit mine engineering. In this work, aiming at the high stress condition of high rock slope, the instantaneous internal friction angle and instantaneous cohesion of rock mass under different stress states are deduced, and the a nonlinear strength reduction method for high rock slope is established according to the relationship between normal stress and shear stress of rock mass under the Hoke-Brown criterion. The numerical calculation results show that the factor of safety (FOS) for high rock slope calculated by the proposed method is more reasonable. Taking the southwest slope of Dagushan Iron Mine as the research background, the safety factors of high rock slope under different rainfall conditions are calculated by COMSOL Multiphysics. And the stability analysis of high rock slope in open-pit mine under rainfall are carried out.


2013 ◽  
Vol 734-737 ◽  
pp. 656-660 ◽  
Author(s):  
Shao Jie Feng ◽  
Shi Guo Sun ◽  
Ya Nan Yi

The critical slip field theory is applied to optimization design of the slope angle. An intelligent matching optimization of the slope angle design is carried out based on the strata distribution, mechanics parameters of rock mass and a given security reserve. That is the implementation of the maximum allowable slope angle of slope rock mass under the given conditions. Optimized by the final highwall of Buzhaoba Open-Pit Mine, the overall slope angle increased 3°compared to the original design. Which implement the optimum slope angle of final highwall, modified the shortcoming in the original design and ensure the maximization of mine safety and the resource exploitation.


2021 ◽  
Vol 2021 ◽  
pp. 1-11
Author(s):  
Zhiheng Dang ◽  
Zuoming Yin ◽  
Desheng Wang ◽  
Mingyu Fu ◽  
Qi Yin

The microparameter calibration of the particle flow parallel bond model (PBM) is mostly based on a uniaxial compression test. The microparameters calibrated only by uniaxial compression tests cannot be directly used to study the mechanical properties of rocks with surrounding pressure conditions. To analyze the relationship between the macroparameters and microparameters in the model and select appropriate particle flow model parameters, this study conducted a particle flow numerical simulation experiment based on the basic test principles of the uniaxial compression, Brazilian splitting, and triaxial compression tests. An orthogonal experimental design was performed for the calibration of the microparameters of the particle flow PBM, and multifactor analysis of variance was used to screen out the factors that have a considerable influence on the experimental indicators. Regression analysis was performed on the significant influencing factors and test indicators, and the corresponding linear and nonlinear relationships between the macroparameters and microparameters were obtained. Lastly, the microparameters of the model were determined in accordance with the macroparameters of the mechanical test of the Barun open-pit mine dolomite, and a numerical simulation test was conducted. Simulation test results were consistent with the actual test results, thus providing a basis for a subsequent numerical simulation study on the mechanical properties of dolomite.


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