Optical dust deposition meter

Coal dust is produced in coal mines during normal mining operations and by the movement of men and machines. The operation of a prototype optical dust deposition meter used to measure the mass-loading density of stratified coal and rock dust layers to assess the flat coal dust hazard is described. The meter determines the surface-loading density of a dust layer by measuring its optical reflectivity. The theory of the prototype unit´s operation is developed and compared with experiment. The studies showed that the prototype unit is capable of measuring coal dust and rock dust surface-loading densities of up to 7 mg/cm² for coal and 10 mg/cm² for rock dust. This is well within the hazard range with an accuracy of about ±5%. Results of the laboratory and experimental mine testing of a second portable meter are reported