A Computer Software Program That Estimates Air Quantity Requirements In Large Opening Stone Mines

The National Institute for Occupational Safety and Health (NIOSH) has developed a computer program called the Air Quantity Estimator (AQE). The purpose of the program is to provide a starting point for estimating the air quantity needed to dilute diesel particulate matter (DPM) in an underground large opening mine, albeit taking into account various input assumptions. The AQE estimates the total air quantity needed to dilute DPM emissions that enter the main airstream of the mine to current statutory levels. It helps operators pinpoint vehicles that are high DPM contributors. In addition, it allows the user to make “what if” scenarios by varying the input parameters to achieve the most efficient and practical ventilation system. The AQE is a stand-alone software program that does not require any type of spreadsheet software. Engine data must be known or estimated with some accuracy and assumptions must be made in order to limit the variability of the program output. Program calculations and two case studies, for validation purposes, are included in this report. It should be noted that the program does not ensure adequate face ventilation and personal exposure compliance. interim limit of 400TC μg/m, and the second to 160TC μg/m. The user can save the input parameters used in the original calculations, then take these data and theoretically add filters to selected engines, replace engines, or change other input parameters. The program will then calculate new ventilation requirements. Thus, mine planners can experiment with many scenarios until an appropriate ventilation system for the site specific conditions at their mine has been attained for the various DPM standards. This program also displays the amount of DPM each vehicle is emitting into the air stream. With this information, the ventilation planner will be able to identify vehicles that emit high DPM emissions. DPM engineering controls may be considered for these vehicles to reduce emissions. [Schnakenberg 2002]. As stated earlier, the results from this program do not ensure proper working face ventilation or personal exposure compliance. If the ventilation air is not effectively directed to the working faces, high concentrations of DPM can still exist even with extremely large amounts of ventilation air in the main mine current. 2 OVERVIEW OF HISTORICAL STONE MINE VENTILATION TECHNIQUES Recent case studies conducted by NIOSH showed that, historically, natural ventilation has been their primary means of diluting airborne contaminates in large opening stone mines [Grau et al. 2002a]. But natural ventilation, by itself, did not guarantee a consistent measurable airflow [Head, 2001]. It provided some air exchange in specific portions of a mine, but the air quantities were generally insufficient and uncontrolled, i.e., not directed to the areas where it was needed. Some mines used fans to increase ventilation airflow, but ineffectively. Commonly, the main mine fans were not installed in a bulk head making them very inefficient. In many cases, the main mine fan and auxiliary fans were improperly sized and/or not placed at the strategic locations throughout the mine. There was modest mine planning in relation with future ventilation techniques. Also, there was minimal use of stoppings to control the direction of air movement. Without consistent ventilation airflow coursing, recirculation of ventilation air and high concentrations of contaminates could potentially be found. 3 PROPER VENTILATION PLANNING IS