Dragan Ignjatovic

Impact of the Bucket Wheel Support at Technical Parameters of the Block and Bucket Wheel Excavator Capacity

Bucket wheel excavators are machines that on the current level of surface mining development have gained the widest application. Its work consists of the main movements (slewing of the bucket wheel and superstructure) and auxiliary movements (moving of the excavator toward advance direction and modification of the height position for the bucket wheel in the vertical plane).

Procjena maksimalnog mogućeg produljenja strijele bagera SchRs740 na osnovi statičkog i dinamičkog proračuna

Professional paper Bucket wheel boom represents the most loaded and the most responsible part of the excavator structure, participating only with 6 to 13 % in the entire excavator weight. Its length is selected depending on the technological requirements of mining deposit, and it has to be adjusted with the designed possibilities of the excavator. At the request of mining technology that is in compliance with the soil-mechanical properties of deposit, conditions for the selection of excavator optimal parameters are created, and therefore for determining the required length of the boom. In this paper, analysis of dynamic and static behaviour of boom extended from 1 to 10m with a step 1m was done. The maximum possible extension is defined as the aspect of the structural performance, dynamic behaviour and stress field. Finite Element Method (FEM) is used to obtain natural frequencies, displacements and stresses.

Energy resources in the Republic of Serbia: Development policy

ABSTRACT By joining the Energy Community and obtaining candidate status for accession to the European Union (EU), Serbia has committed to harmonize its energy policy to the legislation of the EU. The backbone of this policy is the power sector, which will continue to be the foundation of future development. In fact, the power sector is probably the closest to EU standards. This paper presents the energy resources in Serbia and the potentials that can be used to define the power sector policy. It is expected that lignite and large hydropower plants (HPPs) will become the basis of the energy system in the future, but with a significant increase in the share of renewable sources, primarily wind energy and biomass. One of the main objectives is to reach a 50:50 ratio of electricity produced from renewable and non-renewable sources in the period 2020–2030.

Landfill stability analysis at the open pit 'Gacko', Bosnia and Herzegovina - Republic of Srpska

This paper gives the stability analysis of the Western and Eastern external landfill at the Open Pit Gacko, together with the problems that occurred during the last field visit.

Stress and strain analysis in the rock massif during coal exploitation with large diameter boreholes in east field pit RMU Bogovina

This paper presents stress and strain analysis in massif during exploitation of out-of-balance coal layers in the BCM Bogovina. Behavior of the surrounding rock mass was tested during application of large diameter boreholes exploitation. Based on the proposed solutions for stope geometry and known geological conditions in deposit, physical and mechanical properties of coal and surrounding massif, the numerical analysis of the stress and strain of excavation area and surrounding massif was done. Numerical modeling of excavation area behavior was done using the software package Phase2, whose calculations are based on the finite element method. The analysis, conducted in this paper, has shown that there is a possibility for applying this kind of excavation in terms of stability the rock mass.

Defining Parameters of Shear Resistance on Oil Shale Samples

The research environment is a transversely isotropic model, which is characterized with constant physical mechanical properties in different directions in the plane of isotropy, and a different properties in the direction perpendicular to the plane of isotropy. For defining parameters of shear resistance of shale (transversely isotropic model) in three mutually perpendicular directions, it is necessary to prepare 9 (nine) samples, size (8x8x8) [c, using the Mor-Coulombs law, where the destruction of rock happens in plane of the least resistance to shear. This paper presents results got from tests performed in geomechanical laboratory.

Defining the safety pillar of road tunnel above the exploitation field of mine with unstudied subsidence process

This work defines a protective safety belt around the tunnel and excavation limit below the tunnel. Based on these parameters, the limit impact angles are defined, and therefore the geometry of safety pillar.

Defining the shear strength parameters of rocks on preferential planes

The shear test results are presented in this work in the elastic, anisotropy environment in three mutually perpendicular directions. The research area is a transversely isotropic model, which is characterized with constant physical-mechanical properties in different directions in a isotropy plane and different properties in the directions perpendicular to the isotropy plane.