FIELD EVALUATION OF MINE BLASTING EFFICIENCY

The efficiency of drilling and blasting operations can be assessed in different ways, depending on the desired effect. The evaluation can be performed on the basis of the quality of the explosives applied for rock extraction. On the other hand, the correct assessment should include the results of drilling and blasting works. One of the parameters that are commonly used in the quality assessment of explosives is the on-site testing of the detonation velocity, which is a direct indicator of the efficiency of explosives. The quality of explosives is essential for the appropriate blasting process and should be subjected to regular verification by means of measurements under different site conditions. Since in most cases the excavated rock must be transported from the blasting site to another location, one of the main parameters that can be used for drilling and blasting operations assessment is fragmentation analysis. It may be done using various image-based particles sizing software. The article presents selected methods that can be applied for the evaluation of blasting works efficiency, including measurements of detonation velocity as well as fragmentation analysis based on photogrammetric methods.

TESTING THE MACROSEISMIC INTENSITY ATTENUATION RELATIONSHIPS FOR VRANCEA (ROMANIA) SUBCRUSTAL EARTHQUAKES IN RELATION WITH DAMS SITUATED IN EXTRA-CARPATHIAN AREA

The aim of the present paper is to test intensity attenuation relationships for subcrustal earthquakes occurred in Vrancea (Romania) seismogenic zone in relation with some important dams situated in extra-Carpathian area. During centuries, the Romanian territory has been shaken by strong earthquakes, most of them being centered within Vrancea Zone, which is situated at the bending area of the South-Eastern Carpathians. Most of the zones from extra-Carpathian area are affected by the subcrustal seismic events, where many hydro-technical structures exist, being also exposed to earthquakes action. A detailed analysis of the intensity attenuation laws developed for subcrustal seismic sources was performed using the most recent and complete intensity datasets. We use an extended and combined intensity data including historical and modern, qualitative and quantitative data, i.e. a number of 11 earthquakes occurred during the period 1738-2009 with epicentral/maximum intensities ranging from VII-X MSK degrees, and magnitude Mw from 5.4 to 7.9. All the input data used for testing are resulted after the reevaluation and evaluation of the macroseismic effects produced by the seismic events included in the present study (8697 IDP). The selected attenuation laws were tested for different values of epicentral intensity and with reference to twelve and twenty four azimuthal directions. Besides the testing of the relationships, isoseismal maps based on the selected attenuation laws were accomplished, associated to the biggest possible earthquake (worst scenario) for the Vrancea subcrustal zone, also highlighting the calculated intensities in the selected dam sites. Brief description of the study and used methods. Brief description of the study and used methods.

THE ANALYSIS OF SEISMIC LOAD CHARACTRESITIC OBSERVED IN THE LOWER SILESIAN COPPER BASIN

One of the major problems associated with the excavation of the copper deposits in underground mines in Poland is the relatively high level of seismic activity. Numerous high-energy tremors can negatively affect the stability of underground workings and can have a destructive impact on the infrastructure located at the surface as well. As predicted, the seismic activity increases along with the depth of mining operations. Therefore, to face these threats, a number of organizational and technical prevention methods have been applied in the mines. One of them is the assessment of the effect of additional dynamic loads on the structures behaviour with the use of numerical modelling. Recently there have been some possibilities of conducting dynamic analyses, i.e. using the finite element method that allows gathering information on the changes in stress conditions or deformation levels within the analysed object. Unfortunately, these kinds of calculations are usually performed after the occurrence of an unwanted event, so it is rather a post factum method. This is mainly due to the lack of information about the worst scenario of seismic wave distribution. At the same time, during the preliminary risk assessment, in most cases, only the maximum predicted value of seismic wave amplitudes is taken into consideration. Other dynamic parameters such as dominant frequency and duration of seismic wave are usually omitted. In this paper, the time-frequency characteristics of induced seismic waves observed within the Lower Silesian Copper Basin were analysed. Based on the high-energy seismic events database, dominant frequencies, amplitudes and tremor durations were determined. Then the correlation between each parameter, i.e. the energy of each tremor and their hypocentic distance from the seismic source and monitoring station were determined.

OHS RISK ASSESSMENT – A CASE STUDY FOR UNDERGROUND COAL MINING ELECTRICIANS

Risk assessment is a concept introduced for analysing the safety level in workplaces in order to assess if enough and proper precautions have been taken or if their number and quality should be improved so that to prevent hazardous situations. The underground coal mining industry is very hazardous, facing serious fatalities related to work, workplaces and workers as a consequence of the high-risk processes carried out underground and of the hazardous toxic and explosive atmosphere. The use of electrical equipment in such hazardous atmospheres (underground or surface) presents a series of particularities, the workers operating this equipment being exposed to electrical injury. The starting point for the optimization of the activity for preventing work accidents and occupational diseases in a system is represented by the risk assessment of that specific system. Regardless if it is a workplace, a workshop or an enterprise, such an analysis allows the ranking of risks depending on their dimension and the efficient allocation of resources for priority measures. Risk assessment involves identifying all risk factors in the analysed system and quantifying their size based on the combination of two parameters: the severity and frequency of the maximum possible consequence on the human body. This results in partial risk levels for each risk factor, respectively global risk levels for the entire system analysed. In order to facilitate the fulfilment of the legal obligations of the employers in the field of risk assessment of accidents and occupational disease, a relatively large number of methods have been designed and used. Of the many methods used worldwide for assessing the risk of accidents, within this article is used a risk assessment method developed by a Romanian Institute for Research and Development in Labour Safety Bucharest, the paper dealing with a case study in an underground coal hard coal mine carried out for presenting the practicality of this method, in case of assessing the risks of electrical injury of mining electricians.

APPLICATIONS OF SPACE GEODESY METHODS IN ROMANIA

The studies for Recent Crustal Movements by the aid of space geodesy techniques are integrated into the researches on the Earth’s crust dynamics, as a reflection of the complex geodynamic phenomena that occur in the crust and in the subcrustal lithosphere. In addition to the fundamental nature, the research in this field presents a practical characteristic, competing alongside geology and geophysics to the shaping of new energy sources or solid mineral substances, to the determination of the soil stability degree in inhabited areas or in those in which large industrial targets and utilities are intended to be placed in. The knowledge of movements affecting the Earth’s upper crust, movements that precede, accompany or follow the earthquakes, is also a topical issue. The paper presents some of the most important research projects developed in Romania, which were based on the measurement data obtained exclusively by space geodesy methods. There are presented some of the most significant results achieved in the framework of each research project together with the limitations imposed by the used acquisition technology. In chronological order are mentioned first GPS measurements in Romania, started in 1994, in a network centered on the Dealul Piscului observatory, followed by Romania's involvement in a regional geodynamic project, CERGOP and finally a major international project, CRC461, also continued after 2003 with the continuous help of the University of Delft (Nederland), a project that led to the development of an extended network of GPS permanent stations in Romania, all in operating status and whose results are a valuable support for the geodynamic studies. There are made brief references to the first application of the Finite Element Method in a GPS subnet from the Vrancea extended network together with some of the most important obtained results. The strong earthquakes with their catastrophic consequences, which have taken place in recent years on a global scale, similar to that of 4 March 1977 in Romania, have fully demonstrated the need for the knowledge of these types of crust movements in order to contribute, together with other methods, to solve the very complex problem of the earthquake forecasting.

GROUND MOTION PREDICTION AT THE DAM SITES IN SW ROMANIA FOR MODERATE VRANCEA SUBCRUSTAL EARTHQUAKES

The seismic hazard studies of the last 30 years have been largely carried out taking into account the needs of the construction engineers, by linking the specific quantities of soil movement with the physical parameters determined instrumentally, namely, with the maximum values of soil acceleration. At present, interest in the results of hazard studies has increased and has extended to other areas such as insurance or design companies, environmental protection, etc. A fundamental element in the estimation of seismic hazard is the variation of the amplitude of the movement of the soil according to the distance, magnitude and local conditions. To understand and prevent the effects of the strong Vrancea earthquakes in the dam sites located in the South West of Romania, we study the seismic waves attenuation relations using the accelerations recorded by the national network of K2 accelerometers, following the moderate Vrancea intermediate earthquakes. The study area includes the largest agglomeration of dams in Romania, with almost 100 dams out of the 250 large dams. One of the most important specific requirements towards dams' safety is the seismic risk and hazard assessment and the computation of attenuation relationships is one of the most important steps of the work. The main objective of the present work is the evaluation of the specific attenuation relationships of the seismic wave propagating from Vrancea subcrustal focus toward south-west, with direct application for the dams situated in the area.

INFLUENCE OF THE WORLD INNOVATION PROJECT “INDUSTRY 4.0” ON THE DEVELOPMENT OF THE RUSSIAN ENERGY SECTOR

The aim of the article is to attempt to identify the profound changes taking place in the global and Russian energy sectors. One of the key drivers of the new development paradigm is the active implementation of the Industry 4.0 project elements in the fuel and energy complex, which is comprehensive and relies on digital technologies. The features of the global innovation project “Industry 4.0” and, in particular, the digitalization of the oil and gas sector were studied. The possibility of transition of the Russian energy complex to a new development paradigm is also analyzed, it consists in the implementation of elements of the Industry 4.0 project. The problems of the Russian energy sector on the transition to a new development model, which are associated with the features of its production, market and institutional structures, are identified. The theory of value chains in the fuel and energy complex and its upgrade is separately studied. The main niche in the Russian energy sector is highlighted, in which the development of the Industry 4.0 paradigm is possible. Nore: The paper is an extended version of the article presented at the conference SGEM Vienna Green 2019 Conference (9-11 December, 2019), Austria. Reference citation: https://doi.org/10.5593/sgem2019V/1.4The title, abstract was changed in the article / The degree of knowledge of the chains added in the fuel and energy complex was also considered — 3- 4 pp.

THE EFFECT OF MICROFRACTURING IN GABBRO-DOLERITES ON THEIR PHYSICAL PROPERTIES

Simple and cheap methods for the study of building stone deposits for the production of blocks of commercial size can be used to make geological work more efficient. However, physical processes in a massif are hard to understand when doing geophysical research, and the effect of microstructural parameters, mainly the microfracturing of rocks, on geophysical field indices is poorly understood. The authors have studied the impact of microfracturing on the physico-mechanical properties on coarse- to giant-grained rapakivi granites from the Salmi massif, Fennoscandian Shield. The goal of the present study is to assess the physical and physico-mechanical parameters in fine- and medium-grained quartz-free rocks. The authors have studied the various physical and physico-mechanical indices of gabbro-dolerites from the Ropruchei sill (Fennoscandian Shield, within the deposit prospected and revealed the effect of microfracturing indices on them. The study of these properties have shown that microfracturing in gabbro-dolerites is an essential factor which forms the physical parameters of a rock. The testing of this rock type has shown the rate of travel of an elastic wave is clearly related to the microfracturing of samples. The magnetic properties of gabbro-dolerite are due to high concentrations of titanomagnetite, the mineral grains of which formed upon the crystallization of magma during its interstratal intrusion. The distribution of titanomagnetite, based on size and concentration in the rock, depends on liquation conditions in the active stress field. The dependence of the microfracturing of gabbro-dolerites on their iron concentration (FeO+Fe2O3) shows that these «damages» appeared at a ‘brittle” stage in the evolution of the massif in the form of microfractures, the structural parameters of which have inherited the parameters of the stress and deformation field which existed in the massif at that time and which accumulated iron. As a result, microfracturing has a considerable effect on the parameters of the electromagnetic indices of the massif by accumulating iron oxides in the pores, and the higher the index, the higher the geophysical medium indices. Understanding of the physical problem, which accompanies the formation of a gabbro-dolerite complex, helps conduct the geophysical study of a massif, interpret data more objectively and more accurately delineate massive zones in the medium that could be used as high-quality building materials.

HIGH-THROUGHPUT SEQUENCING ANALYSIS OF MICROBIAL POPULATIONS IN ARCTIC ROCK SAMPLE

Recent developments in the existing molecular genetic tools have augmented our current understanding towards the deleterious effects of nanoparticles on human health. During building construction, the rapid generation of nanoparticles has greatly affected to human with severe toxicity by generating free radicals inside their body as potential health hazards. However, there is still need of analyzing nanoparticle toxicity based on the type of microbial diversity present on surface and its potential impacts on human health. In this study, we used rocks as raw material collected from Arkhangelsk (arctic) region of Russia and fabricated into particles of nanometer range in size by planetary ball milling. The paper presents data of the elemental composition on the basis of which the value of the specific mass energy of atomization of the raw material of the rock was calculated. The energy parameters of the micro- and nanosystems of the sample were calculated: free surface energy and surface activity. These nanoparticles were showing minimal cytotoxicity to human embryonic kidney cells in a dose-dependent manner. The high-throughput next-generation sequencing (NGS) was used to perform 16S rRNA metagenomic study for determining the type of microbial diversity present on nanoparticle’s surface. The first highest abundance was found for actinobacteria at phylum taxonomic level indicating a population of gram + ve bacteria having economic importance to human. The second highest abundance was seen for proteobacteria at similar taxonomic level exhibiting population of gram - ve bacteria causing pathogenicity in human. The highest abundance of top 25 microbial species was also discussed in this study. In future, this metagenomic study will also identify other microbial species based on 18S rRNA sequencing.

BIOCHAR AS AN ECO-ADDITION IN WASTEWATER AND WASTEWATER SLUDGE TREATMENT PROCESSES IN NON-URBANIZED AREAS

Especially in non-urbanized areas there is a need to use various waste products, e.g. from agriculture, households, etc. New products that are created in a simple way should be able to be used many times without the use of complicated and expensive technology. This article presents the potential of biochar used in wastewater treatment processes and sludge management in small installations - for the maximum maintained number of users equal to 50. The possibilities of two substances used in sewage management processes, such as char and biochar will be presented. These substances, produced from pyrolysis, are stable carbon-rich compounds which have various beneficial applications like soil conditioning, remediation and wastewater treatment. In particular, biochar originating from wastewater sludge pyrolysis, possible to be generated at the place of formation, was taken into account. In addition, ways to increase the reliability of the treatment plant with biochar based filters are described.