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Management of construction waste that was generated by earthquakes and reconstruction of damaged facilities requires good prior planning of options, as well as good coordination of all institutions during the reconstruction period. The planning should include three main levels: 1 – waste handling in a safe manner, with fast education of persons working on clearing and distribution of means for protection ; 2 – planning of the logistics and temporary storage areas ; 3 – analyses of the shortcomings of the existing legal framework for future waste management in crisis and issue instructions on crisis management of construction and demolition waste. This paper provides an overview of the current crisis management of construction and demolition waste after Zagreb earthquake in March 2020 , identifies challenges with management of such waste, and shows the la test advances in recycling of the problematic streams as an opportunity to advance both, emergency – and usual waste management. In c onclusion it provides recommendations to take following course od actions: 1 - increase of the capacity to recycle, treat and temporarily store construction and demolition waste ; 2 – improve the separation (recycling)process to allow the removal of other wastes and to separate the construction and demolition waste by category ; 3 – focus the activities on research and development of the products from recycled construction and demolition waste (upgrade), especially from the mixed construction and demolition waste ; and 4 – make possible the use of recycled materials in public procurement (including construction and reconstruction of public buildings and infrastructure), prioritise use of construction and demolition waste to stabilize the existing landslides and ground disturbances caused by the earthquakes, facilitate and stimulate the abolition of waste status of materials produced from the construction and demolition waste. Control, separation and/or immobilization of hazardous waste should not be overlooked, as well as the safety of people who handle construction and demolition waste in emergency and afterwards. Legal framework and procedures should be planned and prioritized in advance, thus preventing bottlenecks in communication a nd coordination of regulatory bodies of different levels in the time of emergency.

Faster technology development, increasing of living standard and market availability are the main causes of faster obsolescence of electronic devices. Each electronic device contains printed circuit boards that are a valuable source of metal. The paper presents the results of preliminary research of the possibility for using various mineral processing methods in recycling of waste printed circuit boards. The gravity concentration (concentration table and Humphreys spiral concentrator), electrostatic separation and wet magnetic separation were used in this preliminary research and the obtained results were presented in the article., Szybki rozwój technologii, podwyższenie standardu życia i dostępność na rynku to główne przyczyny szybszego starzenia się urządzeń elektronicznych. Każde urządzenie elektroniczne zawiera płytki drukowane, które są cennym źródłem metalu. W pracy przedstawiono wyniki wstępnych badań możliwości zastosowania różnych metod przeróbki surowców w recyklingu zużytych obwodów drukowanych. W tych wstępnych badaniach wykorzystano wzbogacalnik grawitacyjne (stół wstrząsany i wzbogacalnik spiralny Humphreya), separację elektrostatyczną i separację magnetyczną na mokro, uzyskane wyniki przedstawiono w artykule.

Quartz sand deposit Ravno is the biggest quartz sand deposit in the Dolenjska region in Slovenia with an area of 1.25 km2. Quartz sand at the site is selectively excavated using mechanical methods. Presently, at the processing plant near the deposit, the main final mineral processing technique is flotation. Prior to the flotation, quartz sand undergoes classification and attrition. Final products produced at the plant are natural sand, washed sand and floated sand. Recently, mining companies have been turning to simpler processing systems, such as gravity concentration, due to the price increase of floatation reagents, simplicity of the process and lower environmental impact. Overview of the deposit and current methods used in the processing plant are presented, as a prologue to further work on the process alteration possibilities – a change from flotation to gravity concentration.

Pozvano predavanje obuhvatilo je tematiku značaja EE otpada, gospodarenja EE otpadom i dobrobitima recikliranja električnog i elektroničkog otpada. Dan je pregled tehnologija za recikliranje, napose pri mehaničkom recikliranju te pregled dugogročnih trendova koji se mogu očekivati u budućnosti.

Construction and demolition waste (C&D waste) is one of the most relevant waste types primarily due to large quantities and a high potential for re-use and recycle. This paper discusses the issues related to C&D waste management in the Republic of Croatia. It presents the overview of legislative changes and its impact on the C&D waste management in Croatia. C&D waste quantities per county in the period from 2001 to 2015 are given as well as the expected C&D waste quantities in the future. It is concluded that the legal framework is well established, but it is not implemented consistently. Therefore, it is necessary to plan certain activities and additional resources in order to make the C&D waste management more efficient. The paper also presents the options of C&D waste recycling and describes the recycling technology in a C&D waste recycling plant in the Republic of Croatia. Taking into account the relatively low price of recycled aggregate, long distance transport is not profitable. It is concluded that the use of mobile treatment facilities would be a good practical solution taking into account the underdeveloped infrastructure for C&D waste management.

In the paper, mineral raw materials and waste management policies of the Republic of Croatia are elaborated and compared to European standards and directives. The origin, composition and quantities of waste are provided together with a current status in waste management. Mineral raw materials production and proven reserves are also listed. Waste and mineral raw materials management is commented from the sustainability point of view. Some conclusions are given for the country with a limited mineral raw material resources and potential use of secondary sources.

Waste electric and electronic equipment (WEEE) has the fastest growth compared to other types of waste due to the amount and thus increasing the need for its care about it. Disposal at landfills is not desired by the fact that this type of waste contains a number of useful materials that can be used again, as well as dangerous substances for which disposal is not desirable. This paper presents laboratory tests of separating copper from telephone (UTP and STP) cables that are an integral part of electronic equipment. Testing were carried out by method of gravity concentration using Wilfley shaking table and Humphreys spiral concentrator. The results showed that these devices can be used successfully to obtain copper concentrate whereby better results were obtained at a shaking table., Zużyty sprzęt elektryczny i elektroniczny (WEEE) to najszybciej rosnący strumień odpadów w porównaniu do innych rodzajów odpadów, a tym samym powstaje zapotrzebowanie na jego skuteczne zarządzanie. Unieszkodliwianie odpadów na składowiskach odpadów nie jest pożądane z uwagi na to, że ten rodzaj odpadów zawiera wiele użytecznych materiałów, które można wykorzystać ponownie, a także substancje niebezpieczne, których składowanie wymaga spełniania rygorystycznych wymagań. W artykule przedstawiono wyniki badań laboratoryjnych separacji miedzi z kabli telefonicznych (UTP i STP), które stanowią integralną część sprzętu elektronicznego. Separację przeprowadzono metodą wzbogacania grawitacyjnego na stole wytrząsającego Wilfley i Humphreys oraz separatorze spiralnym. Uzyskane wyniki wykazały, że te urządzenia mogą być z powodzeniem stosowane do uzyskania koncentratu miedzi.

Crushed stone is the most important type of mineral resource in the Republic of Croatia and is mined in more than 350 exploitation fields. Crushed stone is most often used as aggregate for the production of concrete and asphalt, for which it must satisfy high standards, and thus it is necessary to process it. The wet processing technology in semi-mobile plants, which is increasingly frequent in Europe, has thus far not been used in the Republic of Croatia. This paper provides a comparison of the wet processing technology on an older, stationary and a newer, semi-mobile processing plant in the “Oršulica kosa” exploitation field. It also describes the process of waste washwater treatment and the newer high-pressure pre-washing chamber technology. The costs of extracting stone from a stone massif are the same in both cases ; therefore, in comparing the two plants, the effect of the cost of transportation and stone processing was also taken into account. An analysis of the cheapest possible transportation showed that for a stationary plant, located at a distance of 1950 m from the active worksite, the cost of transport was 4.01 kunas per tonne, or 1.7 million kunas per annum, while in the case of a semi-mobile plant this cost was non-existent. As for processing, it appears that the electric energy consumption of a stationary plant is three times greater than that of a new semi-mobile plant, which amounts to a difference of 0.85 million kunas per annum. As for water consumption, it appears that the water consumption of an old stationary plant is approximately ten times greater than that of a new semi-mobile plant, which amounts to a difference of 0.23 million kunas per annum. Taking into account the potential savings of around 2.1 million kunas per annum, the return of the total investment in a new semi-mobile plant should be realized in the relatively short period of 3.5 years. Beside the economic benefit, we should also emphasize the smaller environmental footprint of the new plant, which is evident in the decreased need for adding fresh water to the process, as well as the significantly decreased need for occupying space with settling basins, seeing as the new semi-mobile plant, as opposed to the old stationary one, purifies and recycles wastewater.

The effect of air flow rate, pulp density and particle size was studied using central composite design for coal samples from the Lazy mine. Evaluation of column flotation tests was based on two dependant variables such as ash content and combustible matter recovery in the concentrate. The ash content in the concentrate was from 4.61 to 9.62% with the recovery of combustible matter from 17.43 to 81.98%. The ANOVA statistical analysis showed that the main effect of air flow rate has a significant impact on the combustible matter recovery and ash content in the concentrate. The main effect of pulp density on the combustible matter recovery is significant, whereas for the ash content it is not seen. There is a strong effect of the particle size on the ash content and combustible matter recovery in the concentrate. The interaction of the effect of the pulp density and particle size has a significant impact on the ash content in the concentrate.

Bentonite has vide variety of uses. Sepecial use of bentonite, where its absorbing properties are employed to provide water-tight sealing is for an underground repository in granites. In this paper, bentonite processing and beneficiation are described.

Republika Hrvatska, kao i Europa suočavaju se s nedostatkom mineralnih sirovina i problemom gospodarenja otpadom. Urbano rudarenje nameće se kao neizbježni postupak kojim se racionalno gospodari prirodnim resursima. Iskorištavanje vrijednih sirovina zarobljenih u električnom i elektroničkom (EE) otpadu iziskuje poznavanje sastava otpada i proizvoda nastalih oporabom. Da bi se došlo do novih spoznaja nezaobilaznoje korištenje analitičkog laboratorija i laboratorija za oplemenjivanje i ispitivanje mineralnih sirovina. Rad se bavi aktualnim problemom iskorištavanja i zbrinjavanja otpadnih tiskanih pločica (TP) sakupljenih na prostoru Republike Hrvatske (RH). Obrazlaže svrhu i provođenje ispitivanja sadržaja najznačajnijih metala i ispitivanja mogućnosti iskorištavanja nemetalne frakcije (NMF) TP. Prezentira i okvirne rezultate ispitivanja, kao i ulogu laboratorijskih ispitivanja.

The aim of this paper was to determine the impact of physical and mechanical properties of rocks on the electricity consumption of a jaw crusher during crushing. This paper presents a different approach to determine the energy consumption during comminution. The energy required for crushing rocks was obtained by direct measurement of crusher's motor power during the crushing of samples. Laboratory tests were used to determine the following physical and mechanical properties of the tested samples: bulk density, compressive strength, tensile strength, hardness, and fracture toughness. After that, the laboratory jaw crusher crushing tests were conducted. In the first part of the study, the individual rock samples were crushed one by one. In the second part of the test, multiple samples were crushed simultaneously. By measuring the energy consumption for crushing rocks with different physical and mechanical properties, we explored the dependence of energy required for crushing on individual mechanical properties of rocks and the simultaneous effect of the properties. Using statistical analysis of the influence of individual mechanical properties we found that the greatest influence on energy consumption for crushing was compressive strength. Fracture toughness and tensile strength of the rocks had a significant impact on the crushing energy. The effect of bulk density was not large while for the hardness could not be stated that it had influence. By the analysis of deviations of specific crushing energy calculated using equations obtained by multiple regression analysis of simultaneous influence of multiple mechanical properties of rocks and from the measured values, it was found that the dependence obtained on the basis of all investigated properties showed the smallest deviation and dependence obtained by compressive strength, fracture toughness, and hardness showed significantly smaller deviation. By examining the influence of mechanical rock properties on particle size of crushed material it was found that the increase in compressive strength increased the proportion of larger particles while other properties showed no effect.

The article related to the journal cover is dealing with the legend of the Saint Kinga, the patroness of Krakow miners

Nowadays, electric and electronic equipment (EEE) are an integral part of every household and office and it could be said that EEE entered into every pore of modern society. The rapid technological development in the modern world on the one side brings many advantages but, at the same time causing increase amount of waste and this especially refers to the waste electrical and electronic equipment (WEEE). Capacitors are an integral part of every electronic device and it could be a good source of aluminium. This paper presents research of possibility of aluminium recycling from electrolytic capacitors. Separation of aluminium from the condenser was carried out using wet shaking table. Four different grain sizes were tested. Testing was conducted in laboratory and plant scale. The results showed that it is possible to separate aluminium from capacitors into high quality concentrate.

Nowadays, electric and electronic equipment (EEE) are an integral part of every household and office and it could be said that EEE entered into every pore of modern society. Rapid technological development in the modern world brings as much advantages as it brings bigger amount of waste and this especially refers to the waste electrical and electronic equipment (WEEE). Condensers or capacitors are an integral part of every electronic device. There are many types of capacitors. Aluminium electrolytic capacitors are the most common because their inexpensive electrolytic. The electrolytic capacitors are composed of about 50 % of aluminium by mass and because that they could be a good source of aluminium. This paper presents research of possibility of aluminium recycling from electrolytic capacitors using gravity concentration. Separation of aluminium from the cylindrical shape capacitors in size from 7 to 80 mm was carried out using wet shaking table. Four different grain sizes were tested in plant scale (+8 mm, 8/4 mm, 4/2 mm and -2 mm), while only grain size 4/2 mm were tested in a laboratory scale. The separation efficiency was evaluated on the basis of three parameters: mass yield, aluminium recovery and grade of concentrate. The results obtained in plant scale showed that aluminium recovery and grade of aluminium concentrate increases with decreasing grain size. The best results of recovery of 95.19% and grade of 99.98% were obtained in grain size 4/2 mm, while mass yield was constant at level about 23%. Grain size of 4/2 mm was also tested in laboratory scale and the results showed that small capacitors are more suitable for separation than the larger one. The results showed that it is possible to separate aluminium from capacitors into high quality concentrate.

Soil cleaning technologies are becoming more and more important especially in industrialized countries. Application of soil washing i.e. physical separation results in cleaned soil which can be reused at the origin or the other location. Separated impurities (metals, hydrocarbons) are considered as special waste and further processed and/or disposed on special landfills. Technologies that were originally developed for mineral processing, due to similarity of operative goals – concentration/separation of certain matter adhering to a certain class of grain collective – have a high potential for use in soil cleaning. The purpose of this paper is to give a review of mineral processing methods which can be applied in soil washing technology, and to present some of the processes successfully applied in practice.

The crushing of the mineral raw material is the most essential mechanical operation within mineral processing. It is also an inefficient, energy intensive process that consumes billions of kilowatt-hours (kWh) per year. In fact only 1% of the total energy input into size reduction processes is used in individual particles breaking and changing of solid material dispersion state. Since the technology is well known, improvements in comminution are dependent upon optimizing the application and operation of that technology. The quality of building crushed stone is evaluated on the basis of the physical and mechanical characteristics, the grain size distribution and the grain shape. Schmidt rebound hardness of rocks is the characteristic which is due to its speed and simplicity of testing often applied in practice. The paper presents results of the testing of hardness impact on the crushing energy and product size of the laboratory jaw crusher. Results show that the Schmidt rebound hardness of rock mass does not have significant influence on the jaw crusher power consumption. The high correlation (R2=0, 876) between grain size distribution parameter t10 and Schmidt rebound hardness has been established.

Froth flotation is a process for separation fine solids based on differences of surface characteristics of mineral particles. Separation by flotation is a result of interaction of many variables. The recovery and selectivity depends not only on chemical variables, but also on hydrodynamics of flotation. Hydrodynamics condition in mechanical flotation cell is more turbulent than in flotation column. The paper present results obtained during initial breaking-in of laboratory flotation column on fine coal samples. Optimal dosage value of AF2 collector used in testing was approximately 700 g/t. The best results were obtained by pulp density in range from 50 to 100 g/l. Also, aeration rate should be in range from 24 to 30 l/h. Test with different bubbles sizes showed better result with smaller bubbles.

The objective of the paper was a comparison of classical and column flotation on samples of black-coal slurries from selected localities of okr and poland. Namely they are dukla mine, darkov mine, csm mine, csa mine, doubrava mine and kleofas mine. The acquired results imply that the methods of classical and column flotation are suitable for flotation of the slurries in question as all the tested black coal slurries from okr and poland are cokeable coals with a high flotation ability.

Demand for metals continuously increases so that metal collection and recycling of waste containing metal become very profitable. Firstly, it refers to steel, copper, aluminium, lead, zinc and their alloys. These metals can be collected selectively (aluminium and steel tins), collected as refuse products (old cars, household appliances, electronic waste) or mixed with other materials (municipal waste). Selectively collected metal does not contain other material impurities and it is compacted (baled) and sold as a metal. Waste which contains other materials besides metal has to be recycled. The recycling process usually includes comminution, classification and separation. Crushers and mills are used for comminution, screens for classification and magnetic separators for metal separation. There are two main types of a magnetic separators: separators with slow rotation speed (drum and belt separators) and separators with high rotation speed (eddy-current separators). The former are used for the separation of magnetic materials (steel, iron) and the latter for the separation of nonmagnetic materials (aluminium, copper, lead, etc.). The paper describes the working principle, application and efficiency of magnetic separators in the recycling of various waste.

Silica sand is an important non-metallic mineral raw material within the resources of the Republic of Croatia. Croatian silica sand reserves could meet industrial needs over the long term. The 15 exploitation fields are registered, and the average annual production in the last 10 years is about 240, 000 tonnes. Depending on quality i.e. specific physical and chemical properties (grain size distribution, chemical and mineral composition, moisture content, etc.), silica sand is used as the basic mineral raw material for many industrial applications. To meet defined chemical and physical specifications according to intended application, the raw sand often has to be subjected to extensive physical and chemical processing. The paper describes main beneficiation methods used in the processing of sand intended for industrial uses. Beneficiation procedure applied at the silica sand deposit "Jerovec" located in north-western Croatia is presented, as well as the results achieved under field conditions.

Glass recycling is the process of turning waste glass into usable products. Glass is an ideal material for recycling and in some cases can be used repeatedly without any deterioration in its physical properties. There are several types of glass entering the waste stream each with different chemical compositions and physical properties. Recycling of complex material such as a glass is a simple but hugely beneficial process which consists of several steps. The complete recycling loop can be repeated an infinite number of times and the quality of the glass will never deteriorate. The paper describes recycling cycle, recycling technology and overview of glass recycling state in EU.

Paper is concerning floatability of coal slurries by means of different flotation collectors. The goal of the work was verification of floatability of coal slurries as well as flotation collectors selectivity. The investigation was carried out in a column flotation.

The crushing of the mineral raw material is the most essential mechanical operation within mineral processing. It is also an inefficient, energy intensive process that consumes billions of kilowatt-hours (kWh) per year. In fact only 1% of the total energy input into size reduction processes is used in individual particles breaking and changing of solid material dispersion state. Since the technology is well known, improvements in comminution are dependent upon optimizing the application and operation of that technology. In addition, the design of aggregate crushing plants requires expensive equipment, and missteps in design are difficult and expensive to correct. Unfortunately this often lend to the subjective judgment of an individual, resulting in the conservative over-design of crushing plant equipment. These facts resulted that we tried to find out, on the basis of extensive literature review, which rock mechanical properties are of crucial importance on prediction of jaw crusher performance and to develop large scale laboratory testing system of rock properties that can be significantly correlated with jaw crusher performance.

Paper is concerning floatability of black coal from Mine Lazy by means of Flotalex, Montanol and PE2 collectors. The goal of the work was verification of floatability of mentioned coal as well as flotation collectors selectivity. The investigation was carried out on class – 0, 5 mm in a column flotation. From the flotation results followed that Flotalex and Montanol have approximately equal recovery while Flotalex have better selectivity. Results which were obtained by PE2 collector are not satisfactory.

Mining activity in the Republic of Croatia is based mainly on the exploitation and production of non-metallic mineral raw materials. Since carbonate rocks are predominant in the geological structure of Croatia, in the majority of quarries limestone and dolomite are exploited. Dolomite is widely used in various industries e.g. construction industry, building material industry, metallurgy, glass industry, etc. In glassmaking it is added to raw material mixture in the form of dolomite grits (- 1 mm) as one of the essential components for the input of glass modifiers that is CaO and MgO. To be used for this purpose, dolomite has to meet certain standard specifications established by the glass industry. In most cases, dolomite exploited in quarries does not satisfy demanding specifications and, therefore, its further processing is needed. The paper describes processing technology for dolomite intended for use as a raw material in container glass production. Fe2O3 content in exploited dolomite before beneficiation varies in range from 0.052% to 0.07%. By beneficiation procedure applying dry magnetic separation, dolomite grits with Fe2O3 content less than 0.05%, which meets the requirements of container glass industry, are obtained. The results presented in this paper are achieved under field conditions.

The non-metals and building materials industry accounted for approximately 8 % of the total industrial output in Croatia during year 2004. Nowadays more than 200 trading companies in Croatia deal with the exploitation of solid mineral raw materials, and almost 50 % of them exploit technical stone. In the majority of technical stone quarries, the deposits of carbonate rocks (limestone and dolomite) are exploited, whereas in only eight quarries the eruptive rocks are exploited. If raw material contain impurities, which necessitates wet processing operation, waste water must be cleaned before being let out of the processing plant or returned to the dressing process. In the paper the waste water treatment in technical stone quarry is presented.

The demand for secondary materials, primarly steel, glass and plastics, has led to the significant development and application of new techniques, equipments and plants used in recycling. The paper describes the basic techniques for solid waste comminution and presents the typical machines and equipment used for this purpose. The aim of the paper is to draw domestic industry's and contractor's attention to the production area which in spite of certain production potentials still doesn't exist in Croatia.

The Croatian non-metals industry comprises exploration, exploitation and processing of non-metallic mineral raw materials. By beneficiation of these rock standard stone sizes for the production of concrete, asphalt masses, of supporting layers in road works and railroad ballast were obtained. In most technical stone quarries, rock deposits of a carbonaceous structure are exploited, whereas just some few quarries are exploiting rock deposits of a siliceous structure. An overview of eruptive technical stone production in the Republic of Croatia is given in this paper. The technology of stone exploitation and dressing are shown on quarry Jelenje Vode.

The paper presents the results of attrition cleaning obtained by testing the samples of quartz sand under laboratory conditions. The tests were carried out in two types of laboratory attrition cell – with circular and octagonal cross section, at different values of operating parameters which are supposed to have the main influence upon the attrition efficiency: suspension density, attrition time and stirrer speed. In each type of attrition cell two series of tests were conducted on two quartz sand samples with different SiO2 i.e. impurity contents. Indicators of attrition efficiency were the content of the particles – 0.063 mm and content of main impurities (Al2O3, Fe2O3) removed through the attrition process. By comparing the results of both series of tests conducted in mentioned types of attrition cells, information on dependence of attrition efficiency on feed material composition, operating parameters and attrition cell construction were obtained.

The soil washing process is similar to one applied in mineral processing. In mineral processing the useful mineral component is separated from tailings, and in soil washing relatively small amount of highly contaminated concentrate is separated from the mass of cleaned soil. The washing process includes several stages: soil preparation (pre-screaning and possibly crushing), liberation and separation of individual components respectively, classification, sorting and dewatering. The paper describes the individual stages of washing as well as the most important machines which is used in the process. Personal expirience wtih the application of attrition and column flotation are mentioned.

Flotation is universal method to fine coal processing. Selectivity and efficiency of flotation depends not only on surface characteristics of particles, but also on hydrodynamic condition in flotation cell. The goal of the research was to compare flotation column and conventional mechanical flotation cell in coal flotation. The tests was carried out in both flotation cells in the same conditions. The results indicated that the mechanical cell has greater recovery, whereas the flotation column has a considerably better selectivity since it provides a concentrate of better quality.

The quality of quartz sand can be improved by reducing the oxide coatings on the quartz grains. In this direction, a study has been made to consider the possibility of coatings removal from quartz sand by attrition cleaning. Tests were conducted in a laboratory attrition cell at different values of operating parameters: suspension density, attrition time and stirrer speed. Indicators of attrition efficiency were the content of the particles – 0, 063 mm and content of main impurities (Al2O3, Fe2O3) removed through attrition process.

The greatest part of crushed stone, gravel and sand production is won by open pit operations, whereas gravel and sand partially also from river beds. Its obvious that such a mining activity provoke some changes in the configuration and environmental characteristics of the region, in the temporary or permament disapperance of vegetable or animal species and in the creation of noise, dust and waste water. However, mentioned mining operations shouldn't have only negative effects on the landscape and land potential, but they can discover and predetermine potential of exploited area for various communal purposes after exploitation (eg. sports and recreation centers, campsites, resorts, fish-farms, etc.). In this paper, construction aggregates production in plants located in the vicinity of Zagreb, the capital of Croatia are presented. Advantages and disadvantages of aggregates production in the urban area in the spirit of sustainable development are discused.

Paper is concerning floatability of black coal from Mine Lazy by means of Flotalex, Montanol and PE2 collectors. The goal of the work was verification of floatability of mentioned coal as well as flotation collectors selectivity. The investigation was carried out on class &#8211 ; ; 0, 5 mm in a column flotation. From the flotation results followed that Flotalex and Montanol have approximately equal recovery while Flotalex have better selectivity. Results which were obtained by PE2 collector are not satisfactory.

The production of nonmetallics in Croatia highly exceeds the production of any other mineral raw material. Zagreb, capital of Croatia, is the biggest consumer of sand, gravel and crushed rock aggregates. Since listed materials, due to their low cost, don’t bear long transport, nearby Zagreb numerous quarries and gravel-pits were opened. An overview of sand and gravel production in Croatia is given in this paper. The technology of gravel extraction and dressing are shown on the example of Novo Čiče gravel-pit, together with geological structure of surrounding area and the properties of extracted gravel.

The paper reports on safety at work measures that are carried out at execution of mining operations in technical stone quarries. Since the technological process of stone exploitation consists of several phases, not only safety at work measures, but also specific protective measures for each individual phase are described. During stone exploitation and processing it always comes to dust and waste gases emission, which in some situations can impair the quality of air and environment. Therefore, special attention is paid to sources of dust emission and methods of polluted air purification for certain machines, vehicles, devices and work operation. A processing plant with marked places of dust removal is shown, and work of cyclone colectors and fabric filters is described.

Nowadays, the preservation and improvement of the quality of water, air and soil in the complete system of environmental protection is attended with great care. The most frequent objections in the use of fossil fuels in power plants are directed towards the emission of harmful matters, especially if the thermoenergetic plants are situated in the immeditate neighbourhood or within urban areas. In this paper a review of material particle emissions and emissions of SO2, NOX, CO2, from units of the Croatian Energetic System fed by mazout, gas, and coal has been given. As example, the production flowsheet of the Zagreb Power and Heating Plant (ZPHP) has been investigated, the emission points, from the moment of fuel receptance up to its burning in the boiler, i.e. to the atmospheric gas exhaust, have been identified. Law regulations, control system and the present protecting measures have been described and suitable improvement suggestions proposed.

The main part of the needed metal in the Republic of Croatia is secured by collecting and recycling of metallic scrap, and a part is imported. By collecting and recycling in the year 1998 altogether 113.828 t of various metallic waste has been produced. The iron and steel scrap, which composes 90 % of the whole material, is renovated in two steel plants which in the year 1998 produced 104.114 t of raw steel. With the aim to collect a maximum of metallic scrap a waste stock market has been organized, and 1995 a recycling plant also has been erected. In the paper figures about the import and export of metals in Croatia are given, the technology of the recycling process is reviewed together with the basic figures, and the environmental protection measures in the plant are represented.

The production of technical stone, gravel and sand for the building industry is a very important part of the mining production regarding volume and the financial value as well. The most demanded classes are with grain sizes &#8211 ; 4 and &#8211 ; 2 mm but their production is not always simple. In addition to volume, the specific grain size composition, grain shape and minimal portion of the particles &#8211 ; 0, 09 mm (filler) usually are demanded. Until about ten years ago the portion of the impact and hammer crushers, less often cone crushers were used in the production of these classes. Nowadays the vertical impact crushers (rotor mills) are mainly applied for this purpose. In the paper are presented some of these crushers used in the quarries and gravel-pits in Croatia. Their efficiency (capacity, grain size composition, grain shape, filler portion) depending on the influence of the some technological parameters, as for example grain composition of the feed material, physical-mechanical rock properties, moisture content and etc. are analysed.