Volume 27 (2021): Issue 3 (September 2021)

Analysing environmental impacts of mining activities involves detailed studies of the interactions between technological activities/operations carried out in a mining operation and environmental components affected by them. In order to carry out a more complex environmental impact assessment caused by mining in the eastern part of Jiu Valley on soil and water 4 mining units have been considered in the study, these being mining unit Lonea, Petrila, and Livezeni with their belonging dumps.

Main objective of this research is to analyse the impact caused by mining activities in Eastern part of Jiu Valley by the method of impact networks according to the model “causes - pressures, depreciation of the quality of environmental factors – affected parameters - impact”. Thus, impacts caused by the mining industry were identified based on the top-down typology, being shaped impact networks for underground coal exploitation and sterile material storage on the surface. The metal content of the dumps was also analysed in order to assess the degree of metals soil enrichment compared to the reference concentration of a blank sample. The analysis of the influence of the local rainfall regime aims to highlight the leaching potential of heavy metals in the body of the dump and the possibility of analysing the scenarios of extension of the pollution phenomenon to the saturated area. The study is addressed to researchers, environmental engineers, hydrogeologists and geologists who want to deepen the study of transfer mechanisms of contaminants from dumps to watercourses receiving areas and their dispersion in unsaturated and saturated areas.

Increasing the mining depth at Praid Saline and implicitly the state of stresses and strains determines an increase in the dimensions of resistance structures (pillars and ceilings). Furthermore, the seismic effect generated by the detonation of explosives contributes to the degradation of resistance structures. In order to reduce the destructive effect of drilling-blasting technology a proposal is made for the implementation of mechanized salt cutting technology which makes use of a roadheader. This article emphasizes the technical-economical implementation advantages of exploitation from the lower horizons of the New Sector, those of mechanized mining with a roadheader as opposed to the classical technology of drilling-blasting.

The distribution of power consumption of centrifugal two-shaft disintegrator for impact and shear destruction of material as functions of its technological and structural parameters, as well as parameters of material being ground, has been substantiated. An analytical apparatus has been developed to determine the degree of influence of each factor. Factors affecting the absolute value of the consumed power of the disintegrator have also been established. The results of the work make it possible to optimize the technological process in order to reduce the yield of bream fragments of destruction, which is observed when the share of energy of shear deformations increases, in order to obtain cuboid fractions of disintegration products. They allow to create a methodology for determining the rational parameters of a centrifugal double-shaft disintegrator.

Metallurgical slag is one of the most common industrial wastes. Many of these wastes are not stable over time, by reacting with water and air, continuously generating emissions of heavy metals. Metallurgical slag processing is necessary for at least two reasons: reducing pollutant emissions and broadening the raw material base. The recovery of these slags is very difficult because they are the result of metallurgical processes that aimed to fix metals considered impurities in chemical matrices as stable as possible. This paper presents the initial research on the behavior of metallurgical slags against different leaching technologies.

The paper aims to establish the design elements of the tunnels to be executed on subsection E2 of the Lugoj-Deva highway section, an integral part of the A1 highway. From the multitude of problems related to the execution of a tunnel, the paper investigates the following aspects: geotechnical investigations of the areas to be crossed by tunnels, analysis of tunnel stability, static checks of the final support/lining and, finally, a possible technology for their execution.

The paper presents air quality monitoring in Jiu Valley, which is carried out at HD-5 Vulcan monitoring station, starting with March 2010, allowing the obtaining of useful data for the rapid identification of polluted areas and for taking strategic decisions by competent factors and tactics to combat and prevent pollution. After highlighting the pollution sources in Jiu Valley, we present both the evolution of hourly and / or daily values of pollutants recorded at the automatic HD-Vulcan air quality monitoring station during 2020: SO₂, NO₂, CO, gravimetric PM₁₀, Pb, Cd and Ni, but also the evolution of air quality for quality indicators, monitored in Hunedoara County (including Jiu Valley, at HD-5 station), during 2010-2020.

Taking into account the average annual values of pollutants recorded in 2020 at HD-5 Vulcan station, the paper calculates air quality indices for each pollutant and then indicates air quality throughout Jiu Valley in 2020, establishing that air quality is good in this area, with a very low level of pollution and no effect on humans, ecosystems and materials.

The paper presents a synthesis of the research consisting in a complex capitalization of a brucitic limestone deposit from Romania, in environmental protection, respectively of the complex processing possibilities for using the final products could in a very well defined direction such as: the getting of MgO with 99% purity from a brucitic concentrate with 38-40% MgO content; the getting of a fertilizer containing struvite, limestone and microelements with benefit effects on the acid soils amelioration and on plants growth. The research allowed the establishing of a complex system of three technologies, respectively, one of brucitic limestone processing, the second of magnesia obtaining by brucitic concentrate leaching with carbon dioxide and the third, that of getting a double-role agricultural fertilizer (manure for plants growth and acid soils neutralizer).

The presented article shows a method for finding monitored parameters for creating a diagnostic system for autonomous power sources based on spark ignition engines and diesel engines. The classification of structures of autonomous power sources based on internal combustion engines has been carried out. The analysis of the design features of the most common back-up power sources on the market based on internal combustion engines (ICE) indicates the widespread use of generators with a synchronous alternator. The analysis of the design features of autonomous power supplies has made it possible to develop logical models for different designs. The influence of the occurrence of a faulty state of each element on other elements of the systems is analyzed, and the results of the analysis are summarized in tables. An informative Claude Chenon criterion is proposed for finding the optimal number of diagnostic parameters among an infinite number of possible combinations of physical parameters that characterize the system. When solving the problem, a hypothesis was proposed about the equiprobability of cases of exit from the working state of each of the elements of the system. The use of Claude Chenon allows you to find the parts that make up the generators, which with maximum efficiency reduce the degree of uncertainty in the system. After determining the residual entropy, the parts of the system are selected, the state of which should be monitored by the diagnostic system. For such parts of the system, diagnostic parameters are found and methods for obtaining them are indicated.