Angela Egri’s research while affiliated with University of Petroșani and other places

This paper studies the Roșia Jiu quarry area in Romania. This research highlights the working method of hydraulic excavators and the values of particles released into the atmosphere by them. Improving technological equipment not only helps build a better world, but also restores and preserves the environment. The measurements were made during 2020, using DSM501A sensors, which were located at four points in the quarry, namely in the north, southeast and west of the quarry.

As a result of the exploitation of coal in the mines from the Jiu Valley, significant quantities of tailings result from the mining works, but also from the coal preparation processes. They are stored in piles of different sizes, placed on the ground horizontally or between mountains, piles called tailings dumps. For the construction of tailings dumps the first requirement was the removal of the vegetal layer from the soil surface, a requirement that was often not observed so that the environment was affected. This paper aims to show how the environment around the Vulcan coal mine was affected in 2020..

This paper studies the noise level near the mines in the Jiu Valley using the Bruel & Kjaer Noise Dose Meter Type 4448. The purpose of the paper is to determine the noise level and how it can be reduced so that it falls within the limits imposed by law. The monitoring was done for a period of three months, during which we analyzed and compared the data with the values established by law. The results of our monitoring showed that the noise due to mining activities has a rather influential aspect in terms of occupational safety and security and does not directly affect daily life.

The studied geographical area is situated in a intramontane region situated on the Jiu River called the Jiu Valley, where the main economic activity is mining. The importance of studying this area is related to the effect of coal mining on the climate. Coal extraction in the area led to a change of atmospheric temperature due to the emissions of gases and dust that affects the environment. The use of LM75A sensors allow us to accurately read the air temperature and transmit warning messages when certain temperature intervals are exceeded.

Mining activities for the extraction and efficient use of mineral substances have opened the way to civilization, progress and well-being for many countries of the world, including Romania. This paper analyzes the intramontane area of the Jiu Valley. This paper is based on a public opinion poll conducted in Jiu Valley. The survey was conducted between 16.07.2020 and 16.09.2020 on a sample of 2000 persons, adults over the age of 18 years.

In the coal preparation plant situated in Vulcan, a part of raw coal extracted from the mining units in the "Valea Jiului" is being processed. The small grit coal from circulating waters is concentrated with cyclone batteries and recovered and drained with the help of special screens. The fine tailings from residual water are directed into the slurry decanters and the water is purged using reagents. For appropriate dosing of the reagents, weekly samples of water containing tailings are collected form the slurry decanters. In the following we will analyze and interpret the indicators obtained from the processing of these samples.

Analiza, prelucrarea şi interpretarea principalilor indicatori rezultaţi în urma colectării probelor din decantoarele de şlam steril ale Preparaţiei Coroeşti drd.ing. Şoica Florin Flavius, conf.dr.ing. Egri Angela Rezumat În cadrul Preparaţiei Coroeşti, din Vulcan str. Preparaţiei nr.1, se prelucrează o parte din cărbunele brut extras de unităţile miniere din Valea Jiului. Cărbunele mărunt din apele de circulaţie este concentrat cu ajutorul bateriilor de hidrocicloane şi recuperat, respectiv desecat cu ajutorul ciururilor de desecare. Sterilul fin din apele reziduale este dirijat în decantoarele de şlam steril, după care apa se epurează în prezenţa reactivilor. În vederea dozării corespunzătoare a reactivilor săptămânal se colectează probe din decantoarele de şlam steril. În cele ce urmează vom analiza şi interpreta indicatorii obţinuţi din prelucrarea acestor probe.

This paper presents and analyzes the existing system for controlling the flow of coal on the conveyor with scrapers in a complex mechanized mining component in order to find a better adjustment system. The driving of the imprest and cutting system of mining machine is done by means of a squirrel-cage induction motor. Automatic adjustment of the flow of coal on the conveyor is made by means of a control system which has in the main loop the flow of coal while the secondary loop is the advancing and cutting speed of the mining machine. Speed of advance and cutting speed are considered components of the input vector of mining machines. Induction motors speed control in the imprest and cutting systems is done by a control system with direct orientation on electromagnetic flux of the rotor, sensorless type. The mining machine analyzed in this paper is intended for cutting the coal seams in longwall mining methods.

After the implementation of the new Directives of European Union in the national public procurement system of Romania, the vast majority of public authorities has troubles making direct purchases – especially when using the dynamic purchasing system (SEAP). The new directives (theoretically) are meant to make purchasing easier, cheaper and should involve less bureaucracy, but the new laws passed in Romania seem to overcomplicate the procedures and hold back basic purchases.