Možnosti simulace zpětného proudění kouře v hlubinných dolech pomocí CFD softwaru

The effect of fire generated smoke rollback in underground mines can be dangerous and a potentially fatal threat to all who are endangered by the fire. Three critical stages in the process of smoke rollback are 3D local phenomena that can be analysed by CFD software simulations. With the help of a 3D-CFD analysis we can observe the critical stages of smoke rollback and their reaction to a ventilation network. The CFD provides the opportunity to expand the range of prediction of smoke spread for a wide spectrum of airflows, fire intensities, mine-section inclinations and layouts. The paper deals with the possibilities for simulating the smoke rollback effect in underground mines using the CFD software. For the purposes of this research paper, the PyroSim software from the company Thunderhead Engineering was used to create three different CFD fire scenarios and then observe the critical stages of smoke rollback effects.Zpětné proudění kouře požáru v hlubinných dolech může představovat potencionální hrozbu pro všechny, kteří mohou být jeho dosahem ohroženi. Tři kritické fáze procesu změny proudění kouře jsou 3D místní jevy, které mohou být zkoumány pomocí CFD simulací. Za pomocí 3D-CFD analýzy můžeme sledovat kritické fáze změny proudění kouře a následné ovlivnění větrní sítě dolu. CFD nabízí mnoho příležitostí k rozšíření prognózy proudění kouřů při různých objemových průtocích větrů, intenzitách požárů, v úklonných a horizontálních důlních dílech. Článek se zabývá možnostmi simulace jevu změny proudění kouře v hlubinných dolech za použití CFD softwaru. Pomocí softwaru PyroSim společnosti Thunderhead Engineering byly vytvořeny tři různé CFD scénáře požárů a následně byly pozorovány kritické fáze jevu změny proudění kouře

Methodology for Optimal Fire Evacuations in Underground Mines Based on Simulated Scenarios

The purpose of this chapter is to develop a methodology that will contribute in locating optimal evacuation routes in case of fire that are based on minimal carbon monoxide (CO) exposure during the evacuation procedures. The proposed methodology is tested using simulated fire scenarios from which CO concentration over time curve is extracted from all available evacuation routes and presented in a weighted form based on the accumulating effect of CO inhalation in the form of fractional effective dose (FED). The safety limits of the FED model on which the optimization process is based are determined using a model for the prediction of carboxyhemoglobin (COHb) levels in human blood. The COHb model is associated with predicted clinical symptoms that are the basis for determining the level of incapacitation at which the mineworkers are incapable of completing their evacuation. Also in the process of improving the fire risk analysis, the proposed methodology enables the development of evacuation plans that are based on the results of modeled fire scenarios combined together with the results of the anticipated hazards generated by CO inhalation. The results presented in this chapter indicate a more precise approach in the process of planning the evacuation system inside the underground mines

Methodology for estimation of burned areas caused by wildfires using data from the Sentinel-2 satellite

This research presents a methodology for assessing the extent of areas affected by wildfires, as well as the severity levels of burned areas using multispectral photographs from the Sentinel-2 satellite. As a case study on which the methodology will be applied are the burned areas caused by the wildfires that occurred in early August 2021 in the Pijanec-Maleshevo region of the Republic of N. Macedonia. The advantage of the proposed methodology is that it uses data with completely free access from the Sentinel-2 satellite. The processing and mapping of the results was done in the QGIS software which has open-source license. The obtained results indicate burned areas of 4220 hectares and four burn severity levels (low, moderate-low, moderate-high and high severity). A comparison with the European Forest Fire Information System (EFFIS), which uses multispectral photographs of the MODIS (Moderate Resolution Imaging Spectroradiometer sensor), shows that the proposed methodology improves the burn area estimate by 25 %

Ore losses in underground mines for metal minerals

Ore dilution and ore recovery/losses have an important role in calculating the total reserves of mineral resources. Increased ore losses are causing big production costs and aslo reduces the ore reserves in the deposit and the production life of the mine. The primary goal of this science paper is to present the reasons for ore losses, the economic consequences and the method for calculating the ore losses in underground mines for metal minerals

Fire risk assessment and computer simulation of fire scenario in underground mines

Unsafe working conditions in underground mines have led to a number of accidents, loss of life, damage to property, interruption of production, etc. Safety is essential in mining industry, which in recent years mainly focuses on injury prevention in the workplace through a variety of procedures and employee training. The primary goal of this paper is to present a methodology with systematic analysis to determine the most risky places for fire occurrence in underground mines and using a computer simulation to determine the movement of smoke and fire gases trough underground mining facilities from which depends the safe evacuation of all employees

Opportunities for repairing the unloading bunker on shaft Golema Reka - Sasa Mine

The paper presents a repairing strategy for the damaged unloading bunker in the “Golema Reka” shaft hoisting system, including technology, equipment materials and work organization with special concern for workers safety. Several possibilities are reviewed and optimal approach is defined. Such works are of crucial importance for proper functioning of the “Sasa” Mine hoisting system and could serve as example for similar operations in underground mines

Monitoring of tailing dam reclamation using multispectral remote sensing

For this study, the Google Earth Engine (GEE) platform is used in conjunction with Landsat multispectral images to analyze the vegetation of the Topolnica tailing dam reclaimed area. In 1997, a variety of vegetation was planted on this location, and the reclamation stage of the tailing dam began. This analysis is based on the Normalized Difference Vegetation Index (NDVI) obtained from Landsat multispectral images, which can be analyzed over time to describe vegetation changes. The proposed methodology consists of several steps in which spatio-temporal variability of NDVI classes, surface distribution of NDVI classes and spatio-temporal NDVI trajectory in the reclaimed area of the Topolnica tailing dam for the period from 1997 to 2021 are analyzed together with satellite images for validation. The results of this study have the potential to be used as a tool to monitor and improve the reclamation process in mining regions

Methodology for assessing the spatial distribution and extent of open-pit mines in R. N. Macedonia through remote sensing analysis

Understanding the spatial distribution and extent of open-pit mines is crucial for effective resource management, environmental assessment, and land-use planning. In this study, we employed remote sensing techniques and geospatial analysis to analyze the extent and spatial distribution of open-pit mines in R. N. Macedonia. The methodology involved the utilization of Google Earth Engine and multispectral satellite imagery for the calculation and combining of spectral indices, such as the Normalized Difference Vegetation Index, (NDVI) Normalized Difference Water Index (NDWI) and Enhanced Vegetation Index (EVI). One of the main goals of the methodology is to provide an automated approach for the calculation of the occupied mine extend area and to provide information that can help in the assessment of their impacts on the environment. The findings contribute to a comprehensive understanding of the spatial characteristics and implications of open-pit mining in R. N. Macedonia. Also, this study shows the effectiveness of remote sensing and geospatial analysis and how they can serve as a monitoring tool to assess activities related to open-pit mining

Monte Carlo simulation of uncertain parameters to evaluate the evacuation process in an underground mine fire emergency

DOI nefunkční (16.1.2020)In the process of designing a fire safety system for underground mines, computer fire models can be used to analyse and estimate the consequences of fire scenarios for the evacuation process and the safety of mineworkers. The models need to be fed with data, some of which is stochastic in nature. Recent literature addresses the need for a computationally effective methodology for introducing uncertainties in the input parameters of fire and evacuation models to improve safety in underground mines. This research paper presents the results obtained from a methodology that implements Monte Carlo simulation, which follows the normal distribution of the fire load and the pre-movement time uncertainty to generate multiple scenarios that are simulated in a 3D model to show the propagation of combustion products through the mine ventilation network. These results are then used to estimate the fractional effective dose (FED) of fire combustion products in workers, and the available safe egress time (ASET) and required safe egress time (RSET), which can highlight the safety issues in the evacuation process. To demonstrate the model, a case study of the SASA- R.N. Macedonia lead-zinc mine was used in which 50 variations of scenarios were simulated. The results from the simulations are analysed and potentially harmful fire scenarios highlighted. In addition to being able to identify potentially dangerous fire scenarios, the model can also help in the process of conducting fire risk assessment and in improving the evacuation system in the case of an underground mine fire.Web of Science1191191790

Assessment of the solar energy potential of rooftops using LiDAR datasets and GIS based approach

The importance of solar energy as a global energy source is expected to grow. Solar power's future looks bright, especially with an aged and deteriorating energy grid and rising fossil fuel prices. More precise methods for assessment of solar capacity are needed as more homes and companies investigate the possibility of small-scale photovoltaic (PV) solar installations. In this study, a spatial solar energy PV potential assessment method based on the combination of LiDAR (Light Detection and Ranging) datasets and GIS (Geographic Information System) is proposed. The proposed methodology is applied to an area in the capital city of Skopje in N. Macedonia, from where the results of the possible annual energy output of PV systems for the selected rooftops were presented. The results of the study were presented in a map showing rooftops that are most suitable for installing PV systems. From this map, three random roofs were selected to perform manual estimates of the number of panels that could fit on them and the potential energy output of the solar PV systems. This study provides crucial results for financial and urban planning, policy formulation for future energy projects and also allows to analyze different mechanisms to promote PV installations on publicly available rooftops