Coal reserves in Serbia represent an important strategic energy raw materials on which in the coming decades will be based energy development in Serbia. Coal mining in Serbia is performed by surface, underground and underwater mining, and within each of them there are also the coal preparation facilities. Underground mining is done in the scope of the JP PEU Resavica, which includes eight active mines: Bogovina, Rembas, Vrška čuka, Štavalj, Ibar, Soko, Jasenovac and Lubnica. Surface mining is carried out as part of a JP EPS. Mining operation is done in mining basin Kolubara and Kostalac which are supplier of three thermal power plants: Kolubara, Nikola Tesla and Morava. Underwater mining and preparation of coals in Serbia has been done in Kovin coal mine. Coal production, processes of preparation and quality for all active mines in Serbia are presented in this review paper.

High alkalinity facilitates copper–sulfur flotation separation but also leads to issues such as high reagent consumption, pipeline scaling, and gold loss in tailings. The ore from a copper mine in Serbia contains 2.86% copper, 1.64 g/t gold, and 20.39% sulfur, with copper occurring mainly in covellite and enargite. To achieve efficient separation and recovery of copper–sulfur, a systematic study was conducted using micro-flotation, Scanning Electron Microscopy (SEM), X-ray photoelectron spectroscopy (XPS) and contact angle analysis to investigate the inhibition and activation patterns of pyrite under low and high alkalinity conditions. The results indicate that the combined use of hydrogen peroxide and lime as inhibitor enables efficient separation of pyrite and covellite under low-alkalinity conditions. This effect is attributed to its ability to enhance oxidation of the pyrite surface, which generates more hydrophilic substances. Under low-alkalinity conditions (slurry pH = 10) regulated with hydrogen peroxide and lime in a covellite flotation cycle, and under acidic conditions (slurry pH = 6) in the pyrite flotation cycle, satisfactory results are obtained in both flotation cycles in comparison with industrial data. The copper flotation index was similar, but pyrite and gold recovery increased by 2.3% and ~4%, respectively, over those using lime alone. This process reduced the activator dosage required for pyrite activation substantially, while improving gold recovery. Results demonstrate an efficient method for copper–sulfur separation and recovery, providing theoretical guidance or industrial production processes.

Quartz raw materials for the foundry and glass industries, which must have an appropriate satisfying chemical and particle size composition, according to the standards and special requirements of users, are produced at quartz sand separation plant in Serbia. The process of quartz sands preparation in a separation plant is simple and includes the following stages: screening, washing, classification and attrition. In practice, depending on market requirements, different types of sand from different deposits are processed. In addition, the sands in the deposits are heterogeneous and differ, most often, in the content of clay to be separated, so in many cases it is difficult to satisfy the requirements of consumers. One of the reasons is the lack of automatization, where changes in process flowsheet lead to a stop of process, which entails difficulties in operation and stoppage of this process unit. Taking in the account the above, in order to implement optimal automated control and monitoring of the process, industrial tests were carried out on a separation plant. The tests were carried out on a hydrocyclone of the first stage of classification (as the most important unit of this process), equipped with appropriate control and measuring devices (CMD) to perform this task, namely: a frequency regulator of the pump electric motor and a manometer for measuring the pressure at the feed inlet of the hydrocyclone. In order to evaluate the classification process of various quartz sands in a hydrocyclone, the classification efficiency was determined using partition numbers and a partition curve, and taking into account the parameters of the sharpness of separation. The obtained results of industrial tests have confirmed that as a result of changing the feed pressures of the hydrocyclone, while controlling other technological parameters of the process, it is possible to successfully treat raw quartz sands from various deposits and obtain a product with satisfactory characteristics, especially in regard to particle size distribution. In addition, the results are encouraging in relation to future implementation of automatic process control and appropriate monitoring

This review paper presents the backfill method and materials for paste backfill mathod which are used in the world practice of underground mining. The paper consists of two parts. The first part (Part I) provides a brief literature review concerning the presentation of the backfill method, mostly the paste backfill method, its application, advantages and disadvantages, and materials that can be used to form a paste. The second part (Part II) of the paper presents an overview of possible materials that could be used for the eventual application of this method in Serbia. According to available data, backfill method has not been applied in practice in Serbia today, but mostly laboratory tests have been carried out.