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Cement paste is an already well-known material used in ore mining. It is mainly used to fill excavation areas and the tailings from the surface return to underground mines. In this way, the amount of deposited material and degradation of the surface of the terrain are reduced. The paste itself can be used as an artificial barrier between mining works and underground watercourses. Significant economic and environmental benefits can be expected from using cement paste, which would contribute to sustainable development. The basic materials that make up cemented paste backfill (CPB) are flotation tailings, cement, and water. For CPB to be adequately and safely applied to the filling of excavation spaces and indirectly to the protection of the groundwater, environment, and sustainable development of the mining industry, it must meet certain physical–mechanical, physicochemical, and deformation properties. This paper presents the results of synthesized and analyzed samples of different compositions based on flotation tailings (from the production of ZiJin Copper in Bor, Serbia), cement, and water. The methods used for chemical and mineralogical tests include inductively coupled plasma atomic emission spectroscopy (ICP-AES), atomic absorption spectroscopy (AAS), X-ray diffraction analysis (XRD), and nephelometric turbidity units (NTUs; turbidimetry). The results prepared with CPB consisting of 5% cement, 24% water, and 71% flotation tailings were the most acceptable.

Organizational culture and organizational structure have a correlated interrelationship. Structure determines the behaviors, attitudes, dispositions and ethics that create the work culture. In this paper, the authors analyze the interrelationship between the organizational structure and culture in the mining companies in Eastern Serbia. Investigation was conducted in two companies, with 138 participants in the survey. The research was conducted at the beginning of 2016. The questionnaires included 50 questions concerning the organizational structure and culture, and were anonymous. The results confirmed a significant correlation between the organizational structure and culture in the investigated organizations.

Na proces poslovanja utiče veliki broj faktora, spoljašnjih i unutrašnjih. Neke od ovih faktora menadžeri mogu kontrolisati u potpunosti, a neke vrlo malo ili nimalo. Najmanju kontrolu menadžeri imaju nad faktorima okruženja. Značajan faktor okruženja sa kojim se trenutno susreću preduzeća, a koji utiče na sve sisteme i aspekte poslovanja i procese upravljanja kako velikim sistemima, tako i sektorom preduzetništva, malim i srednjim preduzećima, jeste pandemija virusa COVID-19. U radu se analiziraju izazovi sa kojim se susreću preduzetnici, mala i srednja preduzeća kao i promene koje je neophodno uneti u proces upravljanja preduzećem u doba pandemije. Za istraživanje uticaja COVID-19 na poslovanje kao i za istraživanje uticaja pandemije na proces upravljanja ovim privrednim sektorom korišćeni su sekundarni podaci iz internet izvora kao i publikacija objavljenih u naučnim časopisima tokom 2020. godine. Analize pokazuju da su krizom najteže pogođena novoosnovana preduzeća. Pad preduzetničkih aktivnosti, otpuštanje radnika i zatvaranje preduzeća uočava se kako na globalnom nivou tako i u Srbiji. Autori predlažu neophodno uvođenje novih poslovnih modela kao rešavnje problema koje je prouzrokovala pandemija, kao i rapidno angažovanje određenih veština i sposobnosti menadžera kako bi postojeće pretnje izazvane pandemijom COVID-19 pretvorili u šanse.