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The influence of alternative characteristics of the vicinity of the ventilation district on air quantity

Pach Grzegorz

Archives of Mining Sciences

2020

Vol. 65, no. 1

47--58

Subnetwork with two nodes shared with entire ventilation network can be separated as its part. For the network under common ventilation conditions, one of these nodes will become the subnetwork starting node, while the other will be the subnetwork end node. According to the graphs theory, such a piece of the network can be considered as a subgraph of the graph representing the entire ventilation network. A special feature of that subgraph is lack of predecessors of the subnetwork starting node and lack of successors of the subnetwork end node. Ventilation district of a mine may be often treated as a subnetwork. Vicinity is a part of the network which is not separated as subnetwork. In the case of a ventilation district its vicinity forces air flow through the district. The alternative characteristic curve of the vicinity can therefore be compared to the characteristics curve of a fictional fan that forces the airflow in the district. The alternative characteristics (later in the text: the characteristics) of the vicinity of the ventilation district in an underground mine strongly influence air quantity and therefore play a crucial role in the reduction of methane, fire and thermal hazards. The role of these characteristics and proper selection of their approximating function were presented in the article. The reduction of resistance of an intake stopping (having influence on entire resistance of a ventilation district) produces increased airflow in the district. This changes of airflow in the district caused by a variation in internal resistance (e.g. by opening an internal regulation stopping) depends on the characteristic of the vicinity of the district. Proper selection of its approximating function is also important for this matter. The methods of determination of the alternative characteristic curve of the district vicinity are presented. From these procedures it was possible to obtain the results of air quantities and differences in isentropic potentials between an inlet and an outlet to/from the ventilation district. Following this, the characteristics were determined by graphic and analytic methods. It was proved that, in contrast to flat vicinity characteristics, steep ones have a smaller influence on the airflow modification in the district (which are caused by a regulation of the district resistance). The characteristic curve of the vicinity determines the ability to regulate air quantity and velocity in the district.

Hazard assessment based on fuzzy logic

Grychowski T.

Archives of Mining Sciences

2008

Vol. 53, no 4

595-602

This article presents utilization of fuzzy logic and its inference mechanisms to improve reliability in a decision making process and hazard identilication in monitoring a coalmine atmosphere. These proposed new solutions are based on quality analyses of measured data, knowledge of the dispatcher, as well as subjective interpretation of measurements for hazard assessment. This article presents an example of automatic hazard assessment by monitoring fire and ventilation hazards.

W artykule przedstawiono wykorzystanie logiki rozmytej oraz jej mechanizmu wnioskowania do poprawy niezawodności w procesie podejmowania decyzji i identyfikacji zagrożenia przy monitorowaniu atmosfery kopalnianej. Zaproponowano nowe rozwiązania oparte na analizie jakościowej danych pomiarowych, wiedzy dyspozytora, a także na subiektywnej interpretacji pomiarów przy szacowaniu zagrożenia. W artykule zaprezentowano przykład automatycznego szacowania zagrożenia przy monitorowaniu zagrożeń wentylacyjnych i pożarowych.