Mine Ventilation Networks Analysis Using Node-Loop Method Based on Branches Flow Rates

Summary: Ventilation is one of the most important safety issues in mining operations. Proper analysis of mine ventilation network requires a detailed understanding of air movement in different parts of the mine. Ventilation analysis in medium and large underground mines is complicated and requires numerical modellings to be done. Among the approximation methods of network analysis is the node – loop method which is also known as linear theory method. In Hardy - cross and Newton-Raphson methods, initial guesses are used based on the continuity equations of nodes that are difficult for the large networks and time consuming. The advantage of the node-loop method is that it doesnt need to consider the initial guessing for node equations. Another advantage of this method is the higher speed of convergence for second-order equations. Initially, this method was used in electricity and water distribution networks, but it seldom has been used in mine ventilation network. In this paper, the fundamentals of ventilation network equations and node - loop method are explained. Then the use of this method for solving the equations in mine ventilation is discussed. Network equations are introduced by matrix forms based on branches flow rates. The governing equations for the network and the method for linearization are introduced, followed by a numerical example of mine ventilation network. Finally, Pabdana mine ventilation network has been analyzed by the node-loop method. In this case study, air distribution was calculated in different parts of the mine with good convergence not using initial guess.
Ventilation is one of the most important safety issues in mining operations. Proper analysis of mine ventilation network requires a detailed understanding of air movement in different parts of the mine. Ventilation analysis in medium and large underground mines is complicated and requires application of numerical methods.

Methodology and Approaches: The node-loop method for ventilation network is used in this paper. The practical application of this method is for modeling and analysis of mine ventilation networks. The governing equations and the linearization method are introduced. The advantage of the node-loop method is that there will be no initial guessing for implementing solution. The structured matrixes used are made so that to fit comprehensive ventilation conditions in mines, which includes simultaneous application of fans and natural ventilation.
Results and The node-loop method is shown as an alternative method for mine ventilation networks. The use of this method for solving the equations in mine ventilation is discussed. Network equations are introduced by matrix forms based on branches flow rates. A numerical example of mine ventilation network is followed to better introduce the method. It has also been shown that in this method the speed of convergence is higher for the second-order equations. Finally, Pabdana mine ventilation network has been analyzed by the node-loop method. In this case study, air distribution was calculated in different parts of the mine with good convergence. The operational point of fans is also obtained. The method can be introduced for mine ventilation design and analysis.