Witold Kawalec

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• PhD
• Senior Researcher at Wrocław University of Science and Technology

The increasing use of renewable energy sources, such as wind and solar energy, presents challenges to the stability and efficiency of other energy sources due to their intermittent and unpredictable surpluses. The unintended consequence of stabilizing the power supply system is an increase in emissions and external costs from the suboptimal use of...

Rosnące wykorzystanie odnawialnych źródeł energii, takich jak energia wiatrowa i słoneczna, stwarza wyzwania dla stabilności i wydajności innych źródeł energii ze względu na ich okresowe i nieprzewidywalne nadwyżki, co skutkuje zjawiskiem wyłączania mocy. Niezamierzoną konsekwencją wymuszonego losowością pracy OZE stabilizowania systemu zasilania j...

The growing use of renewable energy sources, such as wind and solar energy, poses challenges for the stability of the energy system due to the appearance of unpredictable surpluses of energy in the system, for which there is no usage and which cannot be stored. This leads to the phenomenon of curtailment of renewable energy supply (RES curtailment)...

Dear ResearchGate participants, I am pleased to inform you that I am guest editing for a Special Issue entitled “Advances in Optimization and Modelling of Coal Mining”, which will be published in Energies (https://www.mdpi.com/journal/energies). Details can be found at the following link: https://www.mdpi.com/journal/energies/special_issues/TW918...

A brown coal mine - a consumer of surplus renewable energy, stabilizing and increasing the security of the energy system

Scientific and technical issues related to the extraction and processing of raw materials are inextricably linked with environmental concerns. The extraction, transportation and processing of raw materials and the creation of new products place a heavy burden on the environment. Therefore, the development of new technologies for the extraction and...

The belt is the most important working element of any conveyor. Damages to this element cause costly downtimes in the operation of the transport system. Due to the working conditions and contact with the material, it is exposed to damage. Proper operation can be the way to effectively extend the life cycle of a belt. The experience of users shows t...

Belt vibration is related to the tension force along the entire length of the conveyor route. The ability to predict belt vibrations can provide information about the correct operation of the conveyor. Vibration analysis is usually based on theoretical models or stationary tests. In this article the vibration frequency of a working conveyor was mea...

Exploitation of lignite in continuous surface mines requires removing masses of overburden, which are hauled to a dumpsite. There are some technological arrangements where the overburden is transported several dozen meters down to a spreader operating on a lower located dumping level. Depending on an angle of a declined transportation route, there...

Knowledge of the particle size distribution of mined ore enables improvement of the main processes of the whole mining value chain: blasting, ore loading and haulage and ore processing. Photogrammetry with image analysis techniques was proposed for the on-line identification of grain size distribution of conveyed ore. Preliminary laboratory tests w...

The mining industry is facing sustainable development challenges, among which the energy efficiency issues seem to be of major importance. As transport of the mined ore is considered as one of the most energy intensive operations, the improvement of its energy efficiency is a key indicator in terms of sustainable actions taken by mining companies....

Belt conveyor (BC) transportation systems are considered to be the most effective for handling large volumes of bulk material. With regards to the rules of sustainable development, the improvement of belt conveyor technology is, in many cases, focused on environmental issues, which include the idea of energy usage optimization. The key issue in an...

Kopalnie są często zlokalizowane w terenie górzystym i urobiony materiał jest transportowany z rejonu wzgórza do doliny-na plac składowy przy drodze publicznej lub bocznicy kolejowej. Stosowany jest wtedy najczęściej transport oponowy, ze względu na swoją niezawodność, ogromną elastyczność oraz dostępność w postaci usługi (outsourcing). Jednak taki...

The rock blasting is the first phase of production in the surface and underground mining operations. Because blasting works affect the efficiency of every activity that follows it, they are considered to play a significant role in the whole mining process. Furthermore, it is stated that the most significant parameter is an ore material fragmentatio...

The ore quality at mining faces in the KGHM underground copper ore mines can be determined based on channel samples and block models built in the Datamine system. Unfortunately, even very accurate information regarding the quality of deposits at mining faces does not translate into the possibility of predicting the composition of feed to enrichment...

Reconciliation between two copper ore mines transferred ore from one mine to another for processing in enrichment plants generated the need to regularly study the amount and composition of the ore on the conveyor connecting these two mines. To ensure the objectivity of the study, taking composite samples and their analysis was entrusted to a specia...

Tracking of a mined ore is now considered as one of the key issues for the needs of improvement of the whole value chain of metal production. Ore beneficiation processes (grinding, milling, floatating) aimed to increase the metal recovery and decrease the energy use as well as reconciliation of mining production depend on the identification of a mi...

The simulation model of the mine transportation system with regard to actual parameters of haul truck inter-arrival times was built in FlexSim. Haul trucks classified by their payload were sampling the rock material from corresponding mining faces. Two main simulation variants (V1 and V2) with a constant overall or mining face specific copper conte...

Identification of the stream of transported mine output has a great importance for the effectiveness of ore processing and for the control of mining operations. The above fact entails the growing importance of various types of scanners and on-line sensors which serve to determine the measurable parameters of a random sample and to use this informat...

Belt conveyors (BC) due to their unmatched capacity are extensively used in all industry applications where large volumes of bulk solids need to be transported. The mining industry is among the greatest BC users that set the new standards of required reliability, durability and operational safety. In recent years the sustainable development of the...

Mean inter–arrival time of haul trucks at the loading points was calculated from the arrival count recorded in a time window of 15 min from five consecutive working days, each of which divided by four shifts. Normality of all distributions was investigated with D’Agostino–K², Anderson–Darling and Kolmogorov–Smirnov normality tests. Courses of most...

Reconciliation between two copper ore mines transferred ore from one mine to another for processing in enrichment plants generated the need to regularly study the amount and composition of the ore on the conveyor connecting these two mines. To ensure the objectivity of the study, taking composite samples and their analysis was entrusted to a specia...

Modelling the flow of a non-homogeneous ore is an important element needed to identify ore parameters for the purpose of ore processing control. The simulation model of the underground ore haulage system with the implemented function of estimating ore qualitative and quantitative parameters was built in the dedicated FlexSim simulation environment...

Assigning transported material with a supplementary information is becoming relevant for the needs of improving the efficiency of industrial processes. In the mining industry annotating the mined ore could bring benefits due to expected decrease of the processing ener gy consumption and increase of productivity. DISIRE project was focused on the im...

This research aims to discuss complex economics of lignite-based energy projects with respect to risk and uncertainty, optimisation, sustainable land use and the importance of lignite as fuel that may be expressed in situ as a deposit of energy. The sensitivity analyses and Monte Carlo simulations performed in this article include estimated land ac...

Information about ore quality along its route from its source – the deposit, through long and complicated belt conveyor system till processing plant is not available in KGHM Polska Miedz on a daily basis. There were only few papers which analyzed variability of Cu content in feed to processing plant, on the transfer conveyor linking two mines and o...

The growing need of reducing the use of raw materials and energy in the chain of supplying goods draws the attention to all aspects of the most energy intensive processes like mining and processing of metal ore. Processing of raw materials strongly depends on their parameters, hence the more accurate identification of them should improve the proces...

Raw material transportation generates a substantial share of costs in the mining industry. Mining companies are therefore determined to improve the effectiveness of their transportation system, focusing on solutions that increase both its energy efficiency and reliability while keeping maintenance costs low. In the underground copper ore operations...

This paper deals with the analysis of the random process of cyclic loading of a mining belt conveyor with portions of ore discharged by loaders or trucks. Such transfer of transported ore from a cyclic to a continuous transport is typical for the specific mining operations implemented in the underground copper ore mines with room and pillar mining....

The need to trace the ore composition in KGHM has been discussed so as to give a processing plant at least one shift advance to adjust beneficiation parameters and optimize efficiency of this process. The discussed DISIRE project proposes dropping to an ore stream on conveyors special tags carrying source data about the origin of loaded ore which c...

This research aims to discuss complex economics of lignite-based energy projects with respect to risk and uncertainty, optimisation, sustainable land use and the importance of lignite as fuel that may be expressed in situ as a deposit of energy. The sensitivity analyses and Monte Carlo simulations performed in this article include estimated land ac...

This research consists of two studies regarding power generation projects. First based upon hard coal and second as joint optimisation of lignite open pit mine and lignite fired power station. Hard coal spreads as fossil fuels combustion competitiveness measure were calculated based on the typical parameters for the Polish hard coal and lignite pow...

Processing of copper ore strongly depends on its parameters, therefore the more accurate identification of them should improve the process efficiency. The ore exploited in the KGHM underground mines in Poland is among the most difficult for processing, mostly due to its differentiated lithological compound. It can be identified at mining faces but...

The effectiveness of enrichment process of run-of-mine copper ore (at KGHM’s ore enrichment plants) depends on the selection of appropriate working parameters of processing machines which are customized mainly to fit the fed rock type. Therefore, the knowledge of lithological composition of run-of-mine copper ore fed to the ore processing plant can...

In Polish underground copper ore mines belt conveyors are the most common transport facilities. In KGHM Polish Copper SA there are over 100 km of belt conveyors. To increase reliability of the transportation system there are built numerous ore bunkers ensuring continuity of the excavation during 5 working days of the week and on weekends, during wh...

The paper presents result of comparison of Cu content variability in three industrial ore streams, that is on section and transfer conveyors as well as the feed for the processing plant. Comparisons were focused only on ore grade variability for consecutive shifts during one month. The samples were taken manually throughout the whole shift from the...

The Polish resources of the copper ore exploited by the KGHM S.A. underground mines are considered as one of the most complex in the world and - consequently - the most difficult to be processed. The ore consists of three lithology forms: dolomites, shales and sandstones but in different proportions which has a significant impact on the effectivene...

The study on the design optimisation of belt conveyors used in the mining industry - the proper selection of carry idlers - aiming to decrease the specific energy consumption of transportation with regard to different operational conditions is presented. High capacity overburden belt conveyors from a surface lignite mine as well as copper ore ones...

The lithological composition of the copper ore delivered to the mills, when recognised in advance, is considered as the most important factor for the proper settings of grinding/milling equipment that can both decrease the specific energy consumption of ore processing and increase metal recovery. In order to address this problem, the idea of the us...

In this paper the methodology of ore sampling on a belt conveyor in one of KGHM Polska Miedz S.A. mines was presented together with the results of analysis of the variation of ore tonnage and quality. The ore was transferred from one mine to another one through the analysed transfer conveyor on the route from the mine Division of Mining to copper p...

To ensure the safe work of a conveyor high values of a conveyor belt safety factor (BSF) are applied for obtaining peak tensions and belt strength. The BSF of steel-cord conveyor belts is derived from the splice dynamics fatigue strength (as identified by the laboratory tests that were made almost half a century ago), as well as degradation from ag...

Condition monitoring of steel cord belts using magnetic scanners is known since late 70s however it has not been widely used in Polish mines due to difficult interpretation of signals and cost of services and diagnostic devices. Recent integrated diagnostic tool developed in Machinery Systems Division at Wroclaw University of Technology showing 2D/...

Theoretical considerations regarding belt behavior has led to depict Weibull distribution as an appropriate distribution function to describe belt segment and belt loop operating time uncertainty. Belt replacement strategies based only on distribution function obtained from statistical analysis of historical data have insufficient precision due to...

Zgodnie z polityką ograniczania zużycia energii, na rynku Unii Europejskiej od ponad 20 lat wiele wyrobów i urządzeń jest oznaczanych etykietami efektywności energetycznej. Sprawdzona w branży AGD koncepcja oznaczania obiektów zużywających energię etykietami energochłonności (A, B, …, G) jest stale rozszerzana, a konieczność zwiększenia efektywnośc...

The paper deals with impact of surface cost on lignite mining project. Not only profitability is discussed but also relations between land owners and a Mine Company. Land acquisition is analyzed and statistics are presented. Surface cost as term is introduced. Investigations are conducted on real data obtained from an already closed pit. Geological...

Warunkiem rozwoju gospodarczego kraju jest utrzymywanie cen energii na poziomie, który umoźliwia przemysłowi skuteczne konkurowanie na rynku międzynarodowym oraz zapobiega ubóstwu energetycznemu społeczeństwa, co jest niezbędne dla stabilnego wewnętrznego popytu na produkowane dobra i usługi. Dla polskiej energetyki oznacza to konieczność utrzymywa...

Belt conveyors seem to be the primary transportation technique for mining materials in many countries, especially it is the case in the mining industry in Poland. One of the key and challenging issue is maintenance policy for conveyor belt, probably the most critical part of a conveyor. The total length of conveyor belts in Polish mining industry e...

Koszty nabycia terenu są istotnym składnikiem kosztów w eksploatacji węgla brunatnego. Wąski margines zysku ze sprzedaży energii zmusza kompanie górniczo-energetyczne do szczególnie wnikliwej analizy wyników ekonomicznych planowanych inwestycji górniczych. Z niezbędną pomocą przychodzą specjalistyczne narzędzia modelowania cyfrowego i optymalizacji...

Koszty nabycia terenu są istotnym składnikiem kosztów w eksploatacji węgla brunatnego. Wąski margines zysku ze sprzedaży energii zmusza kompanie górniczo-energetyczne do szczególnie wnikliwej analizy wyników ekonomicznych planowanych inwestycji górniczych. Z niezbędną pomocą przychodzą specjalistyczne narzędzia modelowania cyfrowego i optymalizacji...

Plany nowych inwestycji górniczych, jak również polityka ochrony złóż, generują poważne konflikty społeczne, których skutkiem może być trwałe uniemożliwienie strategicznych inwestycji górniczych. Autorzy proponują zastąpić stosowane dotychczas środki administracyjne (planowa ochrona złóż, przymusowy wykup terenów dla potrzeb inwestycji górniczej) n...

Plany nowych inwestycji górniczych, jak również polityka ochrony złóż, generują poważne konflikty społeczne, których skutkiem może być trwałe uniemożliwienie strategicznych inwestycji górniczych. Autorzy proponują zastąpić stosowane dotychczas środki administracyjne (planowa ochrona złóż, przymusowy wykup terenów dla potrzeb inwestycji górniczej) n...

The paper deals with impact of surface cost on lignite mining project. Not only profitability is discussed but also relations between land owners and a Mine Company. Land acquisition is analyzed and statistics are presented. Surface cost as term is introduced. Investigations are conducted on real data obtained from an already closed pit. Geological...

Zgodnie z polityką ograniczania zużycia energii (i związanej z tym emisji CO2), na rynku Unii Europejskiej od 1992 r. są stosowane etykiety efektywności energetycznej dla wielu wyrobów AGD. Koncepcja oznaczania etykietami energochłonności (A, B,..,G) obiektów zużywających energię została rozszerzona na samochody i budynki. Konieczność zwiększenia e...

Belt Safety Factor (BSF), applied for identification of required belt tensile strength has not been practically modified for many years according to the valid DIN and CEMA standards. As far as steel-cord belts are concerned the values of splice dynamics fatigue efficiency as established by the laboratory tests that were made almost half a century a...

Machinery Systems Division (MSD) in the Institute of Mining Engineering at Wroclaw University of Technology specializes in belt conveying systems analyzing, calculating and design. Within the division operates the certified Laboratory of Belt Transportation (LTT) and Laboratory of Rollers. Since few years, a group of several people have begun work...

Przedstawiono metodę przetwarzania danych w metodzie symulacji warunkowej w profesjonalnym programie geologiczno-górniczym (Datamine Studio), traktowaną jako wstęp do oszacowania ryzyka przedsięwzięcia górniczego. Elementy metody zilustrowano wynikami uzyskanymi dla analizowanego studium przypadku zastosowania symulacji warunkowej dla zintegrowaneg...

Within the project Technological strategies and scenarios of development and use of rock mineral deposits the Institute of Mining Engineering from the Wroclaw University of Technology together with the IGO (Institute of Opencast Mining) Poltegor-Institute carries out a task to develop a Pilot geoinformation system for rock mineral deposits for a ch...

1) Overview The methods of mineable coal reserves and mineral resources classification and reporting have been changed over the years, independently in various countries. They still have not reached the internationally valid standards despite the fact that premier mining companies carry on their mining operations worldwide. Efforts have been undert...

The financial analysis of a Life-Of-Mine plan of an optimised open pit depends on accuracy of its deposit economic model. The price formula of lignite can be built of its quality parameters and energy market analysis but mining costs depend on a mining system. Once the ultimate pit size and its annual output are set the alternative pit advancing wi...

Application of modern software tools for optimisation of lignite opencast mine operation with regard to belt conveyor system

Sensitivity analysis of lignite ultimate pit size and its parameters on change of lignite base price The influence of lignite base price on the size of ultimate pit (lignite supply) and decrease of lignite quality (decrease of calorific value and increase of sulphur and ash content) has been analyzed. The consequence of these changes is the relativ...

The paper presents methods of operational lignite quality control in the German power industry that base on blending on stockpiles with the extensive use of on-line analysers. Comprehensive improvements of mining and transportation machinery systems as well as burning process in power plants have contributed to significant cost reduction of power g...

The influence of lignite base price on the size of ultimate pit (lignite supply) and decrease of lignite quality (decrease of calorific value and increase of sulphur and ash content) has been analyzed. The consequence of these changes is the relative decrease of real price of averaged lignite and changes of non-discounted pit cash flows. The influe...

The optimisation of design parameters of a belt conveyor for a coal-overburden bench in an open-cast lignite mine has been done. Two criteria of optimisation have been chosen: minimization of belt tension and unitary power. The calculations have been performed for the data from the opencast mine "Betehatow". The chosen and the standard conveyors ha...