Archives 2010

Cuprum Ore Mining Scientific and Technical Magazine
Vol. 57, No.4, 2010

Estimation of costs of conveyor belts operation in a mine using different belt replacement strategies and methods of their failures detection (pol.)

PhD. Eng. Leszek Jurdziak, Dr Eng. Ryszard Blazej

Different models were suggested to estimate costs of conveyor belts operation in a mine including: costs of belts maintenance (incl. application of NDT devices), belt replacements and losses due to belt conveyor emergency stoppages due to belt failures. The increases of belt durability resulting from growing expenditure on their service K_o were taken into account as well as possibility of belt recondition and benefits from application of NDT methods e.g. increase of belt failures detection effectiveness in relation to subjective man made assessment during routine inspection. Achieved results have only qualitative and demonstrative character. Implementation of proposed models in conditions of particular mine requires statistical examinations to identify introduced parameters (e.g. distribution of new and reconditioned belt durability, effectiveness of damages detection, fraction of incorrect decisions) and estimation of real costs of  belt maintenance and losses due to their failures.

Evaluation of  possibility of mining disaster occurrence based on statistical surveys (pol.)

Prof. Andrzej Struminski, Dr Barbara Madeja-Struminska

The paper presents the statistics of mine disasters which happened in Polish hard coal mines between 1945 and 2008. These disasters include mass accidents in which the death toll was 5 or more with regard of underground workers. The disasters were caused by: gas leakages, gas and rock outbursts, methane ignition and explosions, bumps and roof falls, coal dust explosion, fires, heat strokes, water inflows or mining equipment. A concept enabling to predict the possibility of disaster occurrence in hard coal mines was presented. General characteristics of disaster causes is made paying special attention to mining hazards. Probabilistic model of aerological mining disaster development is described as well.

Simulation of a tunnel boring machine (eng.)

Saleh Balideh, Mohammadali Sepehri, Wei V. Liu, Raymond Suglo, Jozef Szymanski, Stefan Planeta 

The operation of a Tunnel Boring Machine (TBM) is modeled using the Visual Simulation Language for Alternative Modelling (SLAM) with AweSim software. Each TBM tunneling cycle consists of the cutting, materials handling and tunnel supporting operations. The operations in the TBM cycle are interdependent and determine the rate of advance of the tunnel. In this paper, two kinds of simulations were done. The first simulation involved the TBM working with one muck car while in the second simulation, two muck cars are allocated to the TBM. The results show that the availabilities of the TBM and muck cars were significantly higher when two muck cars were assigned to the TBM than when one muck car was used. In addition, the rate of tunneling can be accelerated when the materials handling system uses 7 concrete segments per ring of supporting system and two muck cars are allocated to the TBM.

Strength of large storage facilities located within LGOM saltrock against mining activity (pol.)

M.Sc. Bogumila Palac-Walko, Ph.D. Eng. Witold Pytel

Mining operations planned within the Northern part of the Foresudetic Monocline copper ore is associated with a new and extremely important element of the local overburden structure, within which a very thick (up to 300 m) and aerially extended salt rock stratum has been identified. Such a geological conditions may suggest to use salt as a host rock for underground waste storage facilities. However, the understanding of the mechanism of interaction between the salt layer and the overburden different rock strata (dolomite, anhydrite), requires developing a multi-parameter numerical analysis involving rheological and safety aspects of rock mass behavior. The 3-D bedded rock mass model suitable for the "Deep Glogow" area will be developed, utilizing the finite difference method involving rock mass creep behavior as well as bed separation and hard rock pillar failure phenomena.

Rock tests under true triaxial compression conditions (pol.)

M.Sc. Ewelina Fabianczyk, M.Sc. Bogumila Palac-Walko

The paper is based on the review of literature referring to the issue of rock tests
under true triaxial compressive stress conditions. Significant meaning of such tests for materials' anisotropy was indicated.

Cuprum Ore Mining Scientific and Technical Magazine
Vol. 56, No. 3, 2010

Multiple regression model of functional dependency in impact force from height and weight of ram for conveyor belt (eng.)

Dr. Miriam Andrejiová, PhD., Prof. Eng. Daniela Marasová, CSc.

The article presents the regression model of functional dependency on impact force from height of falling and weight of ram for selected conveyor belt. First part of article tests statistical significance of regression model and model's parameters and deals with analysis of random error. The next part of the article deals with identification of outlying and influential data.

Modern mining inclined belt conveyors of reduced energy consumption - Polish projects (pol.)

Prof. Jerzy Antoniak

Reduction of carbon dioxide emissions is an important issue in the XXI century. Energy efficient inclined mining belt conveyors are a significant scientific and technological achievement in this field. Their technical and motor properties are presented in this paper with the examples of belt conveyors installed at Piast, Jankowice and Marcel Hard Coal Mines. This paper considers energy efficiency in a very wide manner - as a decrease of energy consumption by conveyor drives as well as energy efficient production of the conveyor components and their extended durability (especially the belt). Modern belt conveyors also contribute to increased labour safety and a reduction in maintenance crew.

Experiences in the exploitation of conveyor with steel cord belts used for the first time in KGHM's mines (pol.)

MSc. Eng. Andrzej Banaszak, MSc. Eng. Zbigniew Laska

The paper presents the characteristics of "Rudna" mine, discusses the technological process, specifies the structure of belt conveyors system. Describes the genesis of the decision to conduct operational testing of conveyor with steel cord belts, shows the course and results of the laboratory research and the conclusions of the operational tests.

Frames for diagnosing  the condition of belt conveyor drive gearboxes (pol.)

Prof. Walter Bartelmus, Dr Eng. Radosław Zimroz

The properties of vibration signal received from gearbox side as a source of information about the gearbox condition were described. The impact of construction, technological, operational factors and changes of status on vibration signal showing the condition of belt conveyor drive gearbox was discussed. The  design of diagnostic system for driving system of belt conveyor was presented. Evaluation of driving system condition: electric engine, gearbox, driving drum  and stretching drum. The diagnosis of gearbox condition will be based on recorded diagnostic signals (electric and vibration signals, measurement of bearing nodes temperature) and supportive signals (consumed electric power and rotary speed of entrance gearbox shaft).

Problems of safe operation of belt conveyors (pol.)

MSc. Eng. Józef Koczwara

The paper deals with some issues of safe operation of belt conveyors. The requirements of relevant regulations concerning their usage are presented. Special attention is paid to the most frequent errors encountered during their exploitation. Moreover, accidents and fires connected with belt conveyor operation as well as  mine management activities aimed to improve the safety during the conveyor usage are described.

Analysis model for determination of contact loads between tube-shaped conveyor belt of a pipe conveyor and carrier rolls (eng.)

Prof. Eng. Daniela Marasová, CSc., Doc. Eng. Gabriel Fedorko, PhD., Doc. Eng. Karol Kubín, CSc., Eng. Vieroslav Molnár, PhD., Eng. Nikoleta Husáková, PhD.

The article deals with the design of analysis model for determination of the magnitude of the contact loads which are induced by the interaction of the pair of tube-shaped conveyor belt - carrier rolls. The finite element method /FEA/ was used by the creation of analysis model. Analysis model was created in a program Simulia - Abaqus. Obtained results will be the basis of research which is focused on the search of tube conveyor belt dynamic wear creation.

A sensor for detection of fire sources in belt conveyors (pol.)

Dr Eng. Jerzy Mróz, MSc. Eng. Marcin Małachowski, MSc. Eng. Adam Broja

The products resulted from development of a fire source have been characterized in the paper. The most useful sensors for detection of the fires have been selected. A block structure and idea of a construction of a multi-sensor device have been presented. The functions of that device and the signal processing have been described taking especially into account increase in sensibility and elimination of false alarms.The main reasons of the fires in belt conveyors have been shown on the basis of research work in many countries. Allowing for construction of conveyors and their installation in galleries with air flow, the location of sensors has been analysed for the best detection of fires. The developed construction of the multi-sensor device, the tests and analyses will be the basis of development of a system for early detection of fires in belt conveyors.

Research on parameters, characteristic for a source of fire developing in a belt conveyor (pol.)

MSc. Małgorzata Szczygielska, Dr Eng. Jerzy Mróz, Dr Eng. Stanisław Trenczek

The conveyor belts used in the mining have been characterized in the paper. The fires probably caused by belt conveyors have been discussed. A research on temperature profile at a conveyor construction at simulated emergency states has been described. The analyses of gaseous products produced during thermal decomposition of belt samples have been characterized as well. The tests were carried out at laboratory stands of the Institute of Innovative Technologies EMAG. The results obtained and next their analysis will be used for development of a method and a device for early detection of fire sources in belt conveyors.

Predicting the emission of toxic combustion products of conveyor belt fire (pol.)

PhD. Eng. Jan Wachowicz, Dr Eng. Tomasz Janoszek

Fire prevention is always associated with certain discipline and costs. In Polish mining industry each underground fire is analyzed, and special attention is paid on factors which caused the fire, its course and process of extinguishing. Conclusions and recommendations aimed to prevent the similar fires in future are the results of such studies. One of the method which prevent the spontaneous fires is predicting the fire hazard using the special prognostic models based on experimental data. The paper presents a successive mathematical model, with reference to studies [11,8], used to predict the emission of toxic components of fire gases, using selected parameters from cone calorimeter and fire adit, depending on independent air stream velocity and chemical composition of organic master in the mine working of given shape. The importance of finding the appropriate mathematical model, which is very useful in analyzing and predicting the hazard resulting from usage of conveyor belts an other materials, including plastics, what in turn improves the safety in underground mines, was indicated as well.

 

Cuprum Ore Mining Scientific and Technical Magazine
Vol. 55, No. 2, 2010

Current practice in tailings ponds risk assessment (eng.)

PhD. Eng. Witold Pytel

Current practice for risk assessment posed by surface tailings/waste storage facilities is presented. This involves current legislation and regulations applied in EU countries and over the world and the basics concerned with tailings impoundments design as well. It was proved that a current activity at the existing tailings impoundment structures is presently confined rather to field measurements, monitoring and surveillance understood as a basic source for a "real time risk assessment".

Geopolitical and economic risk assessment in the world mining investments (eng.)

MSc. Cezary Bachowski, Dr Eng. Jan Kudelko, Dr Eng. Janusz Nowak

Mining project is a high risk venture and its level depends on the stage of  advancement and its location (country, region). While evaluating the first stage of venture the special attention should be paid on political and economic environment of the country or region where the future project is located. World specialists agree that the project risk level is the highest during the first phase of implementation and reduces with its progress i.e. with acquisition of more data, the better prospection accuracy, enlarging the reserves, metals recovery or determining the necessary investment expenditures. The highest level of political risk will be in countries with unstable social, political and economic situation as well as in countries with high level of corruption. Many financial institutions and banks develop their own geopolitical risk analyses with regard of countries reach in natural resources. The most important elements which are evaluated include: foreign currency liquidity, transfer of financial means, safety of investment, export possibility of produced goods.

Air conditioning of workings in underground mines (pol.)

Prof. Nikodem Szlazak, PhD. Eng. Jan Szlazak

Every year in underground mining more difficult climate conditions are encountered at workplaces. In the nearest future it should be expected that these conditions will go worse with bigger mining depth and increased concentration of mining works. The level of climate hazard in Polish mines is presented in the paper. Sources and ways of heat stream inflow to mine workings are described. Currently used methods of work conditions improvement in mines with high temperature hazard are presented. Basing on air conditioning systems implemented in Polish mines the future trends are described.

Protection at workplace and personal protection measures against thermal hazard in underground mining (pol.)

Dr Eng. Slawomir Gajosinski, Prof. Zbigniew Krolicki

Some solutions used on operator's workplace in mines to limit thermal hazard are presented in the paper. Methods based on air conditioning of closed operator's cabins are characterised. An assessment of effectiveness of such solutions and the comparison with the opened air conditioning systems, which consists in cooled air blow toward unsheltered operator's workplace were made. The alternative for currently used solutions for workplace air conditioning could be cooling vests with their own, independent source of cold or vests connected with the outer generator of cold. In the paper the characteristics of such solutions used in other industrial branches is presented. The effects of their operation and the requirements necessary for their effective work resulting from tests and to date experience, are described as well.

Evaluation of transport and migration properties of fine mixtures used to seal the cavings with regard of their rheological characteristic (pol.)

Dr Eng. Grzegorz Strozik

Abandoned mining areas where extraction of minerals took place without backfilling represent, from one side, areas of intensified surface subsidence risk, and from the other side, a large volume of underground space, which can be filled up with waste or other redundant substances. Also a significant problem in numerous coal mines is utilization of saline waters from their drainage systems. The paper presents results of laboratory experiments on flow and distribution in cavings of slurries containing saline waters and selected types of coal combustion by-products. Authors wanted to expose the role of type of fly ash and concentration of solids on flow properties of grouts in transport pipelines and migration properties after discharge in cavings
area. 16 compositions of slurries made with four types of fly ash have been taken under consideration in hydraulic transport analyze. Additionally a flow of selected slurries in a single rectangular cavity of given aperture has been analyzed using an equation of flow of Bingham fluids between two parallel plates.

 

Cuprum Ore Mining Scientific and Technical Magazine
Vol. 54, No. 1, 2010

Performance tests of MH-620 continuous miner during drifting operations in Lubin mine (pol.)

Dr Eng. Janusz Mlynarczyk, Dr Eng. Leszek Zietkowski

Drifting operations employing continuous miner is a technology which may replace traditional mining using explosives. Bigger progress in headings driving and higher safety level are the main expectations, from the technical perspective, related with new method. Better effectiveness as compared with traditional method is the most expected factor from the economic side. In 2009 the performance tests of MH-620 miner which was driving the headings were carried out in Lubin mine. The tests in Z-702/Z-701 headings were made by PeBeKa. The paper presents the procedure of preparing the miner to the test and the course of the experiment. The information gathered during the tests allowed to present the preliminary evaluation of the miner operation and its drifting performance.

Ventilation network development prospects in the KGHM Polska Miedź SA copper mines with regard to mining extraction of the GG-P deposit (pol.)

Dr Eng. Franciszek Rosiek, Dr Eng. Marek Sikora, Dr Eng. Jacek Urbanski, MSc. Eng. Wieslaw Augustyn, MSc. Eng. Zbigniew Sadecki

Possible methods of providing ventilation and air conditioning in the region of planned mining extraction of the Glogow Gleboki-Przemyslowy deposit are discussed. The major ventilation air conditioning problems resulting from the chosen mine development concept in the GG-P region are presented.

Identification of operating conditions for diagnostics of gearboxes working underground copper ore mine (pol.)

Dr Eng. Radoslaw Zimroz, Dr Eng. Robert Krol, Prof. Walter Bartelmus,

The paper deals with analysis of non-stationary operating conditions for belt conveyor system working in underground copper ore mine as a part mixed (cyclic and continues) transportation system. It as been shown that there is a wide range of non-stationarity of operating conditions that significantly affects diagnostics of dive units elements used in conveyor. Analyses have been done using two sources of data: existing in mine monitoring system of current consumed by electric motors and own equipment and software for rotational speed estimation (speed of input shaft of gearbox).

Rigid inclusion strain gauge transducer for stress change measurements in rock mass (pol.)

MSc. Eng. Mieczyslaw Haladewicz

The article presents the results of research works conducted in KGHM Cuprum Ltd. R&D Centre, which include engineering and examination of the strain gauge transducer for continuous in situ measurements of stress changes in the rock. This is a "rigid inclusion" gauge, made of a material with an elastic modulus E_s much greater than the rock modulus. In the paper, a construction of the transducer is described,  showing how the foil strain gauges and an electronic board are mounted inside a hollow steel cylinder as well as the view of produced models. It also presents general technical data of the transducer and characteristics of output current signal vs. stress changes in the rock and Al block samples. Proposed ways of transmitting transducer output signals to control rooms in the LGOM mines are included.

Measurements of the axial forces variations on expansive roof bolts affected by seismic activity in „A" and „G" area, G-23 panel of Polkowice-Sieroszowice copper mine (pol.)

Dr Eng. Maciej Madziarz, MSc. Eng. Rafal Debkowski, MSc. Eng. Marcin Szpak

The paper describes technical conditions, the course and results of in-situ measurements concerning the dynamic load of seismic activity on expansive roof bolts. Monitoring station was established in the "G" area G-23 panel of Polkowice-Sieroszowice copper mine. Measurements were conduced during one year between 2006 and 2007. Results ware compared with conclusions presented by the last measurements in this theme research.

Possibilities of the closed copper ore flotation tailings deposition places occupancy with energetic plants (pol.)

MSc. Eng. Wanda Tasz, Prof. Leszek Kordas

The preliminary results (based on one vegetation period) of field experiment, located on the flotation tailings deposition place no 1 in Iwiny near Bolesławiec, were presented in the paper. The aim of the work was to determine the influence of the ground (flotation tailings) modification with mineral and organic additives, on the growth of chosen energetic plants, i.e. Miscanthus giganteus, spartina (Spartina pectinata), sunflower (Helianthus tuberosus) and willow (Salix viminalis) and two mixtures of grass and papilionaceous plants. The way of their cultivation was developed as well. For revitalization of copper ore flotation tailings, the organic-mineral materials (i.e. cereal straw, sand gravel, sawdust) were used. These materials and their different mass combinations were the main additives for biological reactivation of tailings. As a result, after addition of organic-mineral materials, the six different grounds (I - VI) - called later objects - were created, and one reference ground (object 0), which was founded on bare flotation tailings. All the applied additives positively influenced on the plant productivity, increasing the dry mass crop from 41,8% (object VI - tailings + straw + sawdust), to 200,4% (object I - tailings + sand gravel) in comparison to the object 0). The highest crops, regardless of applied additives, were obtained from Spartina pectinata (average 80,43 g·m^-2), then Helianthus tuberosus (average 56,66 g·m^-2) and Miscanthus giganteus (average 56,42 g·m^-2). Definitely the lowest crops were obtained from cultivation of the Salix viminalis (11,38 g·m^-2) and mixture no. 2 (22,83 g·m^-2).