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Cuprum Ore Mining Scientific and Technical Magazine

Vol. 60, No. 3, 2011

Strength of Weak Floor Strata Beneath Rock Pillars (eng.)

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

A simplified method for stratified floor strata ultimate bearing capacity (UBC) assessing, in room-and-pillar mining conditions, is presented. The physical problem consists of the following two different cases of rectangular rigid pillar of size B×L resting on a two-layer floor system: (a) with the upper weaker layer of thickness H overlying a stronger, infinite rock deposit. It has been assumed that bearing capacity of floor strata may be analyzed as a shallow foundation problem, using the general bearing capacity equation given by Brinch Hansen with appropriate shape, inclination, and surcharge depth factors, or may be treated as a punching failure problem, particularly in a case of relatively strong upper stratum presence. A broad review of available analytical techniques did show that a finite thickness of the upper weaker layer causes a significant increment/decrement in its ultimate bearing capacity in comparison with homogeneous conditions. The proposed approach has been also validated by numerical modeling utilizing FLAC3D the finite difference computer code.

 

Climate conditions forecast concerning salt deposit workings for alternative connections between the SG and SW-4 shafts (pol.)

M.Sc. Eng. Tadeusz Niespialowski, M.Sc. Eng. Krzysztof Soroko, Dr Eng. Sebastian Gola,  Dr Eng. Slawomir Gajosinski, M.Sc. Eng. Maciej Nowysz

The mine apart from conducting mine works in copper deposits, is also making the development works in salt deposit. Initially the workings in salt deposits are to be driven towards the SG-1 and SG-2 shafts and then towards the currently drilled SW-4 shaft. Those workings are necessary to ensure the constant inflow and outflow of air streams between different areas of the mine. However, because the currently planned workings in salt are of considerable length, driving them will depend, to the great extend, on climate hazards. The paper provides an analysis of alternative routes between the SG-1,SG-2 and SW-4 shafts which can guarantee the  proper climate conditions. Forecasts of the dry and wet air temperature was made for the planned workings in salt deposit taking into consideration two methods: the Voss method and a method based on average density of heat streams. The results were compared with the ones obtained in measurements made underground. 

 

Studies on distributions of parameters of vibration generated by mining tremors in the LGOM mines (pol.)

Dr Eng. Lech Stolecki

The paper presents studies on the relationship between the level of mining tremor impacts on the ground surface and seismic data determined for the analyzed events. The difference between acceleration levels and velocity of vibrations recorded on the surface for events with similar seismic energies located in the same mining field was analyzed for this purpose. In the comparative analyses the geological structure of rock mass, tectonic disturbances in epicenter area of tremors as well as  mining methods  and conditions were taken into consideration.

 

Tests and comparative analysis of two control and operating systems used in ore unloading points (pol.)

Dr Eng. Leszek Ziętkowski, Dr Eng. Janusz Młynarczyk, M.Sc. Eng. Paweł Stefaniak

The reloading point in copper mine is one of the most important places in the transportation chain. The paper presents the tests and comparative analysis of two reloading points equipped with the machine for lumps breaking. First stand is controlled by the operator sitting next to the machine. Second stand is equipped with remote control which is located about 2 kilometers away. The tests were carried out in Polkowice-Sieroszowice mine and the supplier of the equipment was DFM ZANAM-LEGMET Sp. z o.o. 

 

Using wastes from mining activity as a substitute for raw materials (pol.)

Dr Eng. Jan Kudelko, M.Sc. Eng. Dorota Nitek

Tailings from copper ore treatment are one of the troublesome type of waste, with regard to their amount, produced in copper industry. They are collected in tailing ponds. Their storing in tailing ponds is very expensive at present due to high fees for exploiting the environment. This situation results in searching and implementation of new technologies enabling the reduction of the amount of tailings stored in tailing ponds. One of such technologies is the use of tailings for backfilling and isolation of cavings in copper ore mines.

Cuprum Ore Mining Scientific and Technical Magazine
Vol. 59, No.2, 2011

Safety requirements for conveyor belts used in underground workings according to PN-EN 14973+A1:2011 standard (pol.)

Prof. Monika Hardygora, Dr Eng. Dariusz Wozniak

The use of belt conveyors in underground workings requires applying belts meeting the specific safety criteria. New research methods and stands for conveyor belts testing designed for work in underground workings as well as tests used in European Union for assessment of fire-safety and static electricity are presented in the paper. Belts classification taking into consideration the  main hazards occurring in underground conveyor installations are described. The structure of test works and requirements used in determining the category of safety are discussed as well. Authors comment the current Polish system of certification the conveyor belts that are planned to be used in the underground operations. 

 

Environment protection and responsibility for the environment in consolidation transactions of mining companies (pol.)

PhD. Eng. Jan Kudelko

Strategic actions of mining companies are usually concentrated on mineral deposits and possibilities of keeping or increasing their reserves. World trends show that the companies attain that goal by allocating significant funds for exploration or merger and acquisition transactions. For successful consolidation transactions of companies it is very essential to carry out due diligence studies. It includes many dimensions of company activity e.g. financial, legal, management, strategic, human resources and environment protection aspects. The last element is very important considering different industrial branches activity and their influence on the environment. That issue refers particularly to mining companies. The analysis of gathered information enable the assessment of environmental status of analysed company, its position referring to the effects of its activity on the environment and actions taken for environment protection. The above mentioned study enables indication of eventual hazards and risks in the analysed field.

 

Characteristic thermodynamic gas phase of rock mass during mining operations (pol.)

M.Sc. Eng. Wieslaw Grzebyk, Dr Eng. Lech Stolecki

The article discusses the work on developing the method for thermodynamic evaluation of rock mass deformation carried out in KGHM Cuprum Ltd Research & Development Centre. Measurements were carried out in Polish copper mines. The initial results of measurements of thermodynamic parameters of the gas phase of rock mass are presented in the paper. These results provide the basis for the description of deformation process. The ranges of pressure and temperature changes that were measured, were the subject of quantitative analysis. The analysis showed that changes in pressure do not depend on temperature and are the result of changes occurring in the subsurface.

 

Influence of constraint mining conditions on seismic and rock burst hazard in Polkowice-Sieroszowice mine (pol.)

M.Sc. Eng. Karolina Adach

In this paper constraint mining conditions in underground cooper mines were characterized. Seismic activity in D-IE panel and A-5/4 - A-7 protective pillar in Polkowice-Sieroszowice mine was analysed. Moreover, rock burst hazard was estimated and influence of constraint mining conditions on seismic activity and rock burst hazard was shown.

 

Large trucks rear suspension pressures monitoring in oil sands conditions - an artificial neural network approach (eng.)

Jozef Szymanski, Stefan Planeta, D. Apel

Proper maintenance and operation of equipment is essential to any effective mining operation.  Operations at one of the largest oil sand producer rely heavily on truck and shovel methods. The latest generation of haul trucks is outfitted with sophisticated monitoring systems. CATERPILLAR trucks use VIMS, or Vital Information Management System. VIMS includes on-board truck measuring equipment and off-board VIMS software, which enables data download to a lap-top. A record of real time parameters gives a detailed view of what happens to a truck as it performs various functions. The input parameters of great importance are payload, ground speed, rack and pitch values off the machine.  By knowing how these values influence vehicle's rear struts pressures it is possible to assess the remaining fatigue life of the truck's frame.  In recent years neural networks have been widely applied in industry. The most commonly used model is the back propagation multilayer neural network. This technique was applied for prediction of rear cylinders pressure obtained from field testing of Cat 797 (Caterpillar) truck traveling loaded with overburden from electric shovel pit to the dump.

Cuprum Ore Mining Scientific and Technical Magazine
Vol. 58, No.1, 2011

On the need for using mechanical mining in KGHM Polska Miedź S.A. (pol.)

PhD. Eng. Leszek Zietkowski, M.Sc. Eng. Dariusz Teodorski

In the paper reasons for taking action leading to changes in copper ore mining technology in Legnica-Glogow Copper Basin are presented. The need for further tests of mechanical mining methods in KGHM's mines is indicated as well. Mining method using blasting techniques used at present in Polish copper mines is described. Experiments to date from mechanical mining of rock using continuous miner with rotational cutting head carried out in Polish copper mining are characterized. Results of continuous miner operations carrying out mechanical mining during drivage in Lubin and Polkowice-Sieroszowice Mines are presented. Works undertaken in KGHM Polska Miedź S.A. concerning mechanical mining of the deposit using cutter-loader, which are aimed at implementing a new technology for copper ore deposit mining are also mentioned in the paper.

 

Conveyor belt with increased resistance for operational damage (pol.)

Prof. Monika Hardygora, M.Sc. Eng. Henryk Komander, Dr Eng. Miroslaw Bajda 

Belt conveyors are the basic transport equipment in Polish coal, lignite and copper mining. Analysis carried out in mines show that share of conveyor transport in production costs vary from 8 to 30 per cent, depending on the mine type. These costs include energy and operation costs related with conveyors (wearing parts, belts etc.). The paper presents research achievements concerning the conveyor belts, which can be used in mines in order to reduce operating costs of conveyor transport.

 

Using GIS instruments for assessing the mining project during the  prefeasibility study on the example of lignite deposit (pol.)

M.Sc. Eng. Aneta Barańska-Buslik

Proposals of using GIS instruments in prefeasibility study concerning the deposit management are presented in the paper. The issue is described on the example of Zloczew lignite deposit, which is planned to be mined through the open pit. Analytic and design works were carried out using ESRI (ArcInfo) and Bentley's (MicroStation, InRoads, GeoGraphics) software. Type and scope of spatial analysis were determined for each phase of project assessment. The analysis were made using available analog and numerical data. The results allowed to assess the functionality and usefulness of GIS instruments in decision process.

 

The effect of primary stress on underground excavations stability (pol.)

Ph.D. Eng. Jan Butra, M.Sc. Eng. Rafal Debkowski, Dr Eng. Daniel Pawelus, M.Sc. Eng. Marcin Szpak

This paper presents the effect of intensive horizontal stress on underground excavations stability. It describes the protection methods of excavations stability improvement. These methods are using for the mining in the world.