Michael Galetakis

• Professor
• Professor (Full) at Technical University of Crete

This work introduces a methodology for the automatic unmineable inclusions detection and Bucket Wheel Excavator (BWE) collision prevention, using electromagnetic (EM) inspection and a fuzzy inference system. EM data are collected continuously ahead from the bucket wheel of a BWE and subjected to processing. Two distinct methodologies for data proce...

Recent advances in information and artificial intelligence technologies, and more specifically in Fuzzy Logic and Fuzzy Inference Systems (FIS), have provided a new approach in solving many problems related to mineral industry. The aim of the current study is to examine the application of FIS in mineral resources extractive industry by performing a...

Waste concrete is the most predominant constituent material among construction and demolition waste. Current waste concrete recycling is limited to the use of recycled concrete aggregates as a road-base material and less as aggregates in new concrete mixes. Further, the production of recycled concrete aggregates results in the generation of a high...

Lignite plays a dominant role for energy production in Greece, covering over 30% of the demand for electricity generation. Increased energy demand requires, additionally to alternative energy sources, an increase in energy supply from both old and new deposits. Due to the low quality of mined lignite, methods of upgrading in terms of power plants’...

Editorial, special issue of International Journal of Mining and Mineral Engineering on: Advances in Continuous Surface Mining (Guest Editors: Christos Roumpos, Francis F. Pavloudakis,Theodoros Michalakopoulos and Michael Galetakis)

Proceedings of the 14th International Symposium of Continuous Surface Mining, ISCSM2018

This study aims to investigate the lignite ash behavior during combustion for electricity generation and to predict the Ash Fusion Temperatures (AFTs) using ash chemical composition. The studied lignite samples were collected from the area of Ptolemais-Amyntaio at Western Macedonia district of Northwest Greece. Ash chemical composition and its AFTs...

The combustion performance of a bio-solid waste from a wastewater treatment plant was studied in terms of efficiency and gaseous emissions, by carrying out experiments in a bubbling fluid bed unit and was compared with that of an agricultural waste. The effects of excess air and fuel feeding rate were investigated and a factorial design and modelin...

The estimation of hard formations spatial distribution is critical for the planning of the Bucket Wheel Excavator's (BWE) operation. It can be made by the application of geophysical methods in correlation to drilling data and other geological criteria. The main objective of this work was to design an expert monitoring measurement system, intended t...

Long-term strategic planning and scheduling is crucial for successful operation of continuous surface mining projects. It is a complex and multi-objective optimization problem, where the spatial model of the geological and mining characteristics of the deposits is an important issue. The occurrence of geological structures with excessive digging re...

In this paper the preliminary evaluation of the potential of geophysical methods for the detection of geological formations of high cutting resistance and hard rock inclusions during the excavation by bucket wheel excavators (BWEs) is presented. The assessment of the geophysical methods for such applications was based on the findings obtained from...

One of the frequent problems that needs to be addressed when mining coal deposits is the occurence of cohesive materials of high mechanical strength in relation to the other materials of the series. This problem is of particular importance in Europe where lignite deposits are exploited in large opencast mines utilizing Bucket Wheel Excavators (BWEs...

This work describes a methodology for the automatic detection of unmineable inclusions while bucket wheel excavator (BWE) digging, using electromagnetic (EM) sensor and GPS. The overall methodology consists of data collection, pre-processing and evaluation. Two different data evaluation approaches were developed and implemented in Matlab programmin...

This study aims to the development of a Fuzzy Inference System (FIS) that will guide the operator of a Bucket Wheel Excavator (BWE) equipped with geophysical sensors to avoid collision of the excavating buckets with the hard rock formations. The developed FIS uses the probability of occurrence of a hard rock formation (estimated from the measuremen...

The existence of hard rock formation with high cutting resistance, during mining with bucket wheel excavator (BWE), causes frequent stoppages, increased equipment wear, or even severe damage of the BWE. These result to increased idle and breakdown time, to high energy consumption, to low production rate and finally to increased mining cost. A proac...

A methodology for the selection of the optimal land uses of the reclamation of mined areas is proposed. It takes into consideration several multi-nature criteria and constraints, including spatial constrains related to the permissible land uses in certain parts of the mined area. The methodology combines desirability functions and evolution searchi...

Residues from vineyards and wine/spirits industry, as being abundant in S. European countries, were investigated for their application in thermal processes for energy production. The thermal behaviour and the reactivity of the fuels and their blends were determined by thermogravimetric analysis tests. The combustion performance of the residues in t...

Abstarct The project BEWEXMIN aims in the development of solutions to reduce failure rates of bucket wheel excavators operating in difficult mining conditions, where hard rock inclusions and geological formations with high cutting resistance occur. The project includes three main research tasks. The aim of the first task is to define requirements t...

The thermal valorisation of an animal sludge was investigated through combustion and co-combustion experiments with an agricultural residue, olive kernel, in a fluidized bed unit. The performance of the fuels and their blends in terms of efficiency and emissions was tested under different operating conditions. The thermal behaviour and the reactivi...

For the estimation of grade and tonnage of the multiple-layer lignite deposits a sophisticated evaluation methodology, based on exploitation and quality parameters, is used. These parameters are usually determined empirically and the selected values are not always optimal. For the estimation of the optimal values, a new methodology based on respons...

The deposit modelling and evaluation and the mineable reserves estimation of multi-seam lignite deposits is an essential process for mine planning activities. The first approach of the original drill holes data evaluation of the exploration programs refers to the analysis of the in-situ lignite seams characteristics. The algorithm of compositing of...

The performance of bucket-wheel excavators used for the selective mining of multiple-layered lignite deposits is mainly determined by the physical and mechanical properties of the excavated material (digability parameters), as well as by the thickness and the inclination of the excavated layer. The lack of sufficient information regarding the digga...

Continuous surface mining systems, employing bucket wheel excavators, belt conveyors, and stackers, are used in the exploitation of most of the large lignite mines in northern Greece. One particular characteristic of these mines is that the deposits consist of a series of lignite layers of thickness varying from just a few centimeters up to several...

The effect of catalyst addition on ignition and combustion characteristics of biomass fuels from the Mediterranean region, one lignite and lignite/biomass blends, were investigated. Transition metal oxides and alkali/alkaline earth compounds were used as catalysts. The experiments were conducted in a thermogravimetric analysis system. The performan...

Aggregate production is proven crucial for any infrastructure development, including construction work, for the island of Crete (Southern Greece), due to its individual geographical characteristics. Furthermore, since construction has traditionally been a dynamic sector of national economy, aggregate production is playing a major role in the econom...

Several iron ore occurrences are placed in the island of Crete and especially in the prefectures of Chania and Rethymno (Western Crete), some of which have been occasionally exploited. The aim of the present study is the mineralogical examination and the investigation of mineral processing potential of an iron ore occurrence located in the area of...

Lignite is playing a dominant role in the energy sector of Greece, since its contribution to power generation was ~50% in 2011. It is considered a key strategic fuel for Greece ensuring secure of supply at predictable cost. Future exploitation of lignite and other coal deposits in Greece depends on the capability of the coal industry to adapt the e...

During the mine planning of lignite deposits and the designing of the corresponding power plant, it is important to have estimates for both the total tonnage of the deposit and its energy content. However, the calorific value of lignite deposits often is not measured for all drill-hole samples taken during the exploration stage, since its measureme...

This chapter examines Fuzzy Inference Systems (FIS) applications in mining industry using a recent literature review (2000-2010) in engineering and earth science oriented journals. Initially the basic principles of Fuzzy Logic and Fuzzy Inference Systems are presented and an illustrative example of a FIS application, for the evaluation of multiple-...

Aggregates, produced via quarrying operations, are used extensively in the construction industry and are considered vital for the development of any economy. However quarrying has severe environmental impacts such as the emission of dust dispersed in air, water and soil. The utilization of the accumulated dust during aggregates production is thus c...

Lignite in Greece is mainly extracted by continuous surface operation by using bucket wheel excavators, belt conveyors and spreaders in combination with noncontinuous methods which employ mobile equipment. The combination of the two systems above could be considered as a unconventional process in open pit mining and there is a strong necessity for...

The effect of uncertainty sources to the stochastic optimization of the combined project of a new surface lignite mine exploitation and power plant operation for electricity generation is investigated. Major sources of uncertainty that were considered are the reserves and the quality of the lignite. Since probability distribution functions for thes...

Olive tree prunnings, one lignite and their blend were burned in a lab-scale fluidized bed facility, at different air/feed ratios. Emissions of CO, SO 2 and NO x were measured and combustion efficiency was determined. Fly ashes and bed material were characterized in terms of mineralogical, chemical and morphological analyses and the slagging/foulin...

Surface mining operations can adversely impact the environment. The size and nature of earth-moving works carried out for the exploitation of mineral deposits can cause severe environmental problems unless the mining company plans and implements an effective environmental protection and land reclamation programme. Such a programme starts from the e...

The effect of uncertainty sources to the stochastic optimization of the combined project of a new surface lignite mine exploitation and power plant operation for electricity generation is investigated. Major sources of uncertainty that were considered are the reserves and the quality of the lignite. Since probability distribution functions for thes...

In this paper the development and the application of a fuzzy expert system for the evaluation of the exploitable reserves of multiple-layer lignite deposits, mined by continuous surface methods, is presented. The exploitable reserves are determined decisively by the structure of these deposits, as well as by the limitations of the used mining syste...

Carbon dioxide emissions were shown to vary with the calorific value and carbonate content of lignite burned at three large power plants. Carbon dioxide emission factors for these power plants ranged from 1.18 to 1.43 tons of CO2 MW−1 h−1. These emissions must be reduced to minimize the cost of CO2 certificates required by the Emission Trading Sche...

A sustainable coal industry needs to achieve a number of objectives including improvements in utilization of deposits, energy efficiency, and environmental performance during combustion. The “Clean Coal Concept” promises to combine the secure and low cost electricity supply offered by hard coal and lignite with adequate environmental precautions. I...

Mine reclamation is an integral part of the mineral development process. The selection of land use after the mine closure is a difficult decision, which is complicated further because of the variety of parameters that must be taken into account trying to provide the local community with a viable development plan. Conventional methods used for recla...

One of the main issues in large-scale mining projects with a long-term horizon is the deter-mination of the production rate. This rate de-pends on the technical characteristics of the mineral deposit as well as on economic, market, environmental or other constraints. The objectives of this paper are (a) to review known mine capacity models and to a...

In this paper a methodology for the long-term prediction of the CO2 emission factor, based on 2D models of selected lignite quality parameters and on strategic mine planning, is presented. The calculation of the CO2 emission factor was based on the calorific value of the lignite and the efficiency and oxidation factor of the lignite fired power uni...

In this article, an analytical method for the prediction of dual energy transmission performance, based on uncertainty analysis, is proposed. Comparison of theoretically computed errors to those estimated during the trial operation of dual energy transmission analyzers installed in the lignite mines of Megalopolis and Ptolemaes (Greece), shows that...

The present contribution investigates the way of applying benchmarking for large-scale open-pit mining operations based on sustainability indi-cators proposed by numerous institutions or groups of experts. These indicators have been developed taking into consideration the legal and regulatory framework that are in force. However, their scope is not...

In this study, models were developed for the estimation of CO2 emissions from lignite- fired power plants based on routinely measured quality parameters of lignite and the power-plant efficiency. These models could be incorporated into the production scheduling optimization plan of the lignite mining. A probabilistic methodology for uncertainty ass...

Greece, mining 65-70 Mt annually, is the second lignite producer in the EU, fifth largest in the world. South Field Mine (SFM) is the biggest mine in Greece with an overall production exceeding 20 Mt per year. The SFM can be considered unique regarding the mining conditions and the methods used to remove the overburden material. Approximately 30% o...

The energy and climate protection policy of European Union (EU), and its Member States adopted in 2007 bridges security of supply, environmental protection and competitiveness. The objectives of the EU energy and environmental strategy cover the foreseeable period till 2020. It assumes all sources of energy will be needed. The objectives for renew...

This paper proposes a new approach for calibration of dual gamma-energy transmission (DUET) ash analyser for improved on-line analysis of run-of-mine lignite. An adaptive neuro-fuzzy inference system (ANFIS) was developed to model the relationship between the intensities measured by the scintillation counter of the analyzer and the measured ash. Sa...

The feasibility of exploiting a mineral deposit by developing a surface mine is closely related to the environmental protection and land reclamation costs. This issue has utmost importance for West Macedonia Lignite Centre (WMLC) of Greece, where there is still a lot of interest for opening of new mines and for further development of the existing o...

A sustainable coal industry needs to achieve a number objectives concerning mainly with superior utilisation of deposits and improved environmental performance. Modern quality control systems, which are greatly based on the on-line analysers, play an important role in achieving sustainability targets. This paper discusses the testing and applicatio...

The difficulties that rise during the evaluation of multiple-layer lignite deposits come from the deposit structure (alternating lignite layers with intercalated material of varying thickness), as well as from the limitations of the applied selective mining. Thin layers of lignite and interbedded waste layers are grouped under specified assumptions...

Brown coal exploitation in Greece is of primary interest because it is an abundant domestic energy resource that contributes more than 70% in total electricity production. Greek brown coals present challenging and diverse technological characteristics, which should be studied to design and manage efficiently the mining, as well as, the operation of...

The quality of lignite mined from the Lignite Centre of West Macedonia is characterized by an intensive variation, due to the nature of the deposit and dilution during the selective mining. Conventional coal processing and controlling techniques, that are possible to improve the lignite quality, by reducing its moisture and mineral matter contents,...

An experimental approach to develop a new building product consisting mainly of limestone dust, which is considered as waste or by product material of aggregates industry and a small quantity of ordinary Portland cement, is presented. Limestone dust and cement were mixed, humidified and compacted under high pressure in a cylindrical mould, to form...

During the design phase of any mining operation, it is very important to ensure ore production with specific quality characteristics, which are mainly established by the standards of each consumer. While high and medium frequency quality variations of the ore, can usually be compensated using homogenization and/or mixing techniques, and appropriate...