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Number of results: 8
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Abstract

Pod ziemią metan jest zabójcą. Pojawia się nagle i miesza się z powietrzem, tworząc silnie wybuchowy gaz. By móc go szybko i bezpiecznie usunąć, trzeba dysponować sprawnym systemem wentylacji i monltoringu gotowym na każdy scenariusz.
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Authors and Affiliations

Wacław Dziurzyński
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Abstract

This paper describes the concept of controlling the advancement speed of the shearer, the objective

of which is to eliminate switching the devices off to the devices in the longwall and in the adjacent

galleries. This is connected with the threshold limit value of 2% for the methane concentration in the

air stream flowing out from the longwall heading, or 1% methane in the air flowing to the longwall.

Equations were formulated which represent the emission of methane from the mined body of coal in the

longwall and from the winnings on the conveyors in order to develop the numerical procedures enabling

a computer simulation of the mining process with a longwall shearer and haulage of the winnings. The

distribution model of air, methane and firedamp, and the model of the goaf and a methanometry method

which already exist in the Ventgraph-Plus programme, and the model of the methane emission from the

mined longwall body of coal, together with the model of the methane emission from the winnings on

conveyors and the model of the logic circuit to calculate the required advancement speed of the shearer

together all form a set that enables simulations of the control used for a longwall shearer in the mining

process. This simulation provides a means for making a comparison of the output of the mining in the

case of work using a control system for the speed advancement of the shearer and the mining performance

without this circuit in a situation when switching the devices off occurs as a consequence of exceeding

the 2% threshold limit value of the methane concentration. The algorithm to control a shearer developed

for a computer simulation considers a simpler case, where the logic circuit only employs the methane

concentration signal from a methane detector situated in the longwall gallery close to the longwall outlet.

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Authors and Affiliations

Wacław Dziurzyński
Andrzej Krach
Teresa Pałka
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Abstract

Underground methane can be highly lethal, appearing suddenly and mixing with air to form a strongly explosive gas. Dealing with methane quickly and safely requires an efficient system of ventilation and monitoring, ready for any scenario.
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Authors and Affiliations

Wacław Dziurzyński
ORCID: ORCID
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Abstract

This paper presents mathematical models enabling the calculation of the distribution and patterns of methane inflow to the air stream in a longwall seam being exploited and spoil on a longwall conveyor, taking into account the variability of shearer and conveyor operation and simulation results of the mining team using the Ventgraph-Plus software. In the research, an experiment was employed to observe changes in air parameters, in particular air velocity and methane concentration in the Cw-4 longwall area in seam 364/2 at KWK Budryk, during different phases of shearer operation in the area of the mining wall in methane hazard conditions. Presented is the method of data recording during the experiment which included records from the mine’s system for automatic gasometry, records from a wireless system of eight methane sensors installed in the end part of the longwall and additionally from nine methane anemometers located across the longwall on a grid. Synchronous data records obtained from these three independent sources were compared against the recording the operating condition of the shearer and haulage machines at the longwall in various phases of their operation (cleaning, cutting). The results of the multipoint system measurements made it possible to determine the volume of air and methane flow across the longwall working, and, consequently, to calculate the correction coefficients for determining the volume of air and methane from measurements of local air velocity and methane concentration. An attempt was made to determine the methane inflow from a unit of the longwall body area and the unit of spoil length on conveyors depending on the mining rate. The Cw-4 longwall ventilation was simulated using the data measured and calculated from measurements and the simulation results were discussed.

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Authors and Affiliations

Wacław Dziurzyński
ORCID: ORCID
Teresa Palka
Andrzej Krach
ORCID: ORCID
Stanisław Wasilewski
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Abstract

The closure of deep mines, featuring multi level seam extraction, lasts many years. During this time period, the ventilation system must ensure adequate working conditions, and ensure the safety and stability of fan operation in gas and fire hazards conditions. The analysis of air flows and methane inflows during the progress of mining mine excavations closure, is the primary object of the article. Execution of such analysis requires knowledge of the mining mine excavations’ closure schedule, the structure of the ventilation system under consideration, the values of the parameters describing the air flows delivered to the mine excavations, and the current characteristics of operating fans and predicted methane exhalation. A computer database, currently being updated by a mine ventilation department for the VentGraph-Plus computer software, has been used simulate the various ventilation scenarios experienced, during the final stage of closure, including the shutdown of the main fans and the backfilling of shafts. The results of case study, containing 2 variants of simulated examples, are presented in the form of diagrams of methane concentration changes in time at characteristic places of the mine. The completed simulations of ventilation processes during the closure of mine excavations and transfer of inflowing methane, indicate useful possibilities of the computational tool used.
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Authors and Affiliations

Wacław Dziurzyński
1
ORCID: ORCID
Jerzy Krawczyk
1
ORCID: ORCID
Teresa Pałka
1
ORCID: ORCID
Andrzej Krach
1
ORCID: ORCID
Przemysław Skotniczny
1
ORCID: ORCID

  1. Strata Mechanics Research Institutes of Polish Academy of Science, 27 Reymonta Str., 30-059 Kraków, Poland

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