The Air Quantity Estimator (AQE): A New Computer Software Tool 

for Large-opening Mine Ventilation Planning 

Objective

 To provide operators of large-opening mines with a 

ventilation planning tool that will help them develop a healthier, 

safer, and more efficient ventilation system in the underground 

workplace. 

Background

 In 2002, regulatory standards were enacted in the United 

States that limit the allowable diesel particulate matter (DPM) 

concentrations in underground mines. Mine operators have 

several engineering controls available to reduce DPM emissions 

from engine exhaust, including the use of catalytic converters, 

filters, low-sulfur fuel, and cleaner burning engines. In addition, 

administrative controls, such as regulating the length of time a 

diesel-powered vehicle operates underground, may also effectively reduce DPM concentrations. Finally, DPM concentrations can be reduced by increasing the overall ventilation 

airflow in the mine. Increased ventilation airflow can be 

achieved by installing large-volume fans and using stoppings or 

auxiliary fans to direct this ventilation air to the working face of 

the mine. To help mine operators evaluate their site-specific 

conditions for DPM control as part of the mine planning process, 

NIOSH engineers have developed a computer software tool 

called the Air Quantity Estimator (AQE). The AQE addresses 

the ventilation needs of large-opening (typically at least 40-ftwide and 20-ft-high) metal/nonmetal mines. 

Using the AQE

 The AQE is a tool to help operators of large-opening mines 

in estimating adequate underground mine ventilation based on 

site-specific diesel engine emissions. It is a user-friendly personal computer program that operates under all Microsoft 

Windows operating systems of Version 95 or later. The AQE is 

a stand-alone software package and is not dependent on the 

installation of any commercial spreadsheet program. It contains 

a User's Guide and a Help Menu to assist in running the program. 

 Before running the AQE program, specific engine data and 

operating parameters must be entered into the base spreadsheet 

(Figure 1). Engine emissions data, including the DPM emission 

rate, must be known or estimated with reasonable accuracy. To 

aid in this process, the program has features to help determine the 

DPM emissions input data for those engines approved by the 

Environmental Protection Agency and the Mine Safety and 

Health Administration. For engines where emissions data are not 

available, guidelines are provided for estimating the required 

input values. Operational assumptions associated with each 

engine used underground, such as the percent of underground 

operating time (percent of DPM emission time per shift), must be 

made to limit the variability of the program output. 

 Once the input data are entered into the program, the AQE 

calculates and displays an estimate of the total ventilation airflow 

needed to dilute DPM emissions to the statutory interim 

concentration of 308EC μg/m3

 (Figure 2). The AQE also determines the air quantity required for the 160TC μg/m3

 DPM concentration level that is proposed for the future. The two calculated 

air quantity estimates will provide mine planners with a starting 

point for long-term ventilation planning, including choosing 

properly sized fans to provide the required ventilation airflow. 

 Another benefit of the AQE is that it allows the mine 

operator to conduct "what if" evaluations by varying the input 

parameters to achieve the most efficient and practical fleet of 

diesel-powered vehicles and ventilation system configuration. 

Theoretical changes to the operating engine input, such as the 

addition of filters, use of cleaner engines, and administrative 

controls, can be evaluated with the AQE. The results of the 

"what if" evaluations allow the mine operator to determine which 

current vehicles are contributing the greatest amounts of DPM 

into the main airstream of the mine. A systematic plan for using 

available engineering controls or replacing these vehicles can then 

be developed to minimize their impact on the current mine-wide 

ventilation requirements, including reducing DPM emissions. 

Summary

 A combination of engineering, administrative, and ventilation controls will eventually be required in many largeopening mines in the United States to meet the regulatory DPM 

concentration limits. The AQE is an excellent tool for mine planners 

to use to estimate site-specific ventilation requirements for

No. 514 March 2006 
Figure 2.—AQE spreadsheet with sample output results. 

their mine, as well as to evaluate options to meet the regulatory 

DPM concentration limits. The AQE reduces the reliance on trialand-error practices for ventilating large-opening mines. Its use will 

result in more efficient and effective ventilation systems and a 

healthier underground workplace for large-opening metal/nonmetal 

mines. 

 

How to Order the AQE

 For more information on the AQE, contact Roy H. Grau III 

(412–386–6562; RGrau@cdc.gov) at the NIOSH Pittsburgh 

Research Laboratory. 

 A free copy of the AQE software can be downloaded from: 

www.cdc.gov/niosh/mining/products/product4.htm. You may 

also contact Joy Lamars at 412–386–6472, e-mail: 

JLamars@cdc.gov. Or you may complete the order form below, 

detach, and mail to: Joy Lamars, NIOSH Pittsburgh Research 

Laboratory, Cochrans Mill Rd., P.O. Box 18070, Pittsburgh, PA 

15236–0070, or fax to 412–386–6595. 

To receive other information about occupational safety and 

health topics, call 1B800B35BNIOSH (1B800B356B4674), or 

visit the NIOSH Web site at www.cdc.gov/niosh

Mention of any company name or product does not constitute 

endorsement by the National Institute for Occupational 

Safety and Health. 

DHHS (NIOSH) Publication No. 2006–124

C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C C 

G Please send me a free CD containing the AQE software (includes User's Guide). 

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Figure 1.—AQE spreadsheet with sample input values.