Over the past fifteen years, engineers from Mine Ventilation Services, Inc. (MVS) have measured numerous friction factors at many different types of mining operations. The results of these measurements indicate that standardized friction factors referenced in most ventilation textbooks are greater than those measured in the field for similar airway support systems. Many referenced friction factors are still based on G. E. McElroy\u27s classic paper Engineering Factors in the Ventilation of Metal Mines published in 1935. Most mechanized mines now incorporate airways that are larger, have more advanced support systems, and more uniform openings. This paper describes the measurement techniques and results from friction factor measurements taken during ventilation surveys at various mines with differing support systems. A comparison between textbook and measured values is also presented
