Some different possible solutions to the problem of industrial waste originating from primary aluminium production (also known as SPL) have been investigated. The latest techniques to treat SPL are presented, with the highlight being flotation and chemical treatment technology. Laboratory tests confirmed that the SPL treatment model is not feasible and viable within partial solutions. Only the systematically achieved solution can be in accordance with a wide range of contemporary demands. Partly, the cause is the allotropic form of the carbon cathodes produced and partly also the impurities in the waste material that prevent an effective one-phase treatment. Laboratory investigations of reactive extraction open up the possibilities for wide SPL material utilization. The preliminary inquiry confirms that the interdisciplinary approach leads to open solutions leading to possible market interest or generated value from the waste as the main goal of a circular economy.

In existing underground mines of dimensional (natural) stone in Slovenia, including the Lipica II and Hotavlje I quarry, the geomechanical characteristics have been observed concerning safety pillars with a low width-to-height ratio. The initial height of safety pillars usually amounts to 4.5 m, but with deepening of underground spaces it increases by 3.0 m; in places, it may reach values of up to 25.0 m or even higher. In previous years, special attention was paid to the installation of stress-strain systems for controlling the planned dimensions (width and height) of large open underground spaces (rooms) and the dimensions of high safety pillars, along with continual monitoring and identification of instability phenomena in the ceiling and sides of large open spaces (rooms). The paper presents procedures for the planning, optimization and monitoring of high safety pillars for underground excavation of natural stone blocks.

The aim of the research was to identify the influence of different microencapsulated reaction time on the morphology, size, infrared spectral, thermal and micromechanical properties of melamine formaldehyde microspheres, synthesised with modified in situ polymerisation. Microspheres are microencapsulated particles with a blurred boundary of the core and shell due to their same composition. The synthesis of microspheres was paused after 1, 3, 9 and 15 h, and stopped after 23 h. The scanning electron microscopy and granulometric analysis were used to study the morphology and size of microspheres. Regardless of the reaction time, the produced microspheres were spherical in shape and with a rough surface. The average size of microspheres was almost identical (0.709–0.790 µm), while the volume size distribution curve of the particles became narrower with prolonged reaction time. The curing mechanism of melamine formaldehyde resin was studied using the Fourier-transform infrared spectroscopy and thermal analysis, and nano-indentation identification. The results revealed a slightly more crosslinked structure: with minimal (neglected) increased thermal weight loss (only up to 0.5%) and minor increased Young’s modulus (up to 2.3%). Using a nano-indenter, the hardness of synthesised particles improved by up to 14.8% after 23 h reaction time.

Compared to the major industries, mining industry has a high risk accident potential. Over ten thousand miners are killed every year, and this is just the official figure. It is assumed that the number of the injured might exceed one hundred thousand miners, and many of them remain disable [1,2]. The history of mining is linked to the development of society itself, while the regulations on mine safety can be traced back to the Roman times. Significant mining accidents and disasters were reported since the beginning of the year 1800 [2,3]. Several pathways to mine accidents have been identified within the 200-year experience, where the agents have been: hit, inrush, outbursts, explosion, falling, sliding, lifting, poisoning, etc., in different work places, such as stope-work, transport, drift-discharge, transport, maintenance, etc. Despite having identified the causality (agent) long time ago, the number of mining accidents are still disturbing. This paper aims to assess the risk from particular agents at a workplace, trending this way to determine the risk rank through empirical formulas, through parameter "P" as an accident occurrence parameter and relevant statistics on mining accidents. Figure 2 Risk ranking based on accident categorizationAccording to Table 3 and the results given in Figure 2 showing the exponential and logarithmic curves, we attempt ranking risk areas, blue as the lower risk, orange as the medium to high risk, and red describes disasters. If we refer to the risk calculation for the Stan Terg mine (A = 60%), the graph shows a high degree of risk, while based on the above analysis (Fig.1.), the most dangerous workplaces at this mine are those related to production (stope mining). CONCLUSIONSThe determination and assessment of risk at the workplace, and identification of the causes of the accidents will neither eliminate all mine risks, nor will identify all probable hazards. However, these will make safety managements at different mines aware of the risks to be able to increase mining safety and increases alertness.The main conclusion of this research is the determination of dangerous of working places, based on the parameter in Formula 3, 4 and 5 not only for calculating the risk at the workplaces, but also the reliability of the result itself. Consequently, we found that the most dangerous workplaces at Stan Terg mine are those related to production (stope mining). The findings of this research lead to recommending further specifications in the accidents reports, such as the mine name/type, exact date and time, workplace, agent-s/causes, activity at time of accident, equipment involved, management behaviour, type of injury (fatality, serious, small), individual/collective, occupation of the deceased, age, summary events and recommendations, etc. This way, we will increase the power of statistical data, and consequently we will increase the quality of risk determination and its calculation at the workplace, i.e. mine site. This way, it will increase the quality of management safety at mines, ...