Some mineral product industry sites include equipment and processes that involve aggregate crushing.
Particulate emissions occur whenever aggregate and rock are mechanically shattered.
A series of meetings was held in 1995 and 1996 between AWR Consultants, the San Diego County Mineral Products Industry, and the District regarding particulate emission estimation techniques applicable to aggregate operations. This policy included a standardized approach to evaluating emissions from mineral industry aggregate crushing operations. In general, it was decided to classify all crushing operations as either primary crushing, dry process material crushing, wet process material crushing, dry fines material crushing, or wet fines material crushing. Standardized PM10 emission factors were assigned to each classification based on the expected annual average particle size distributions and moisture contents. Predetermined fugitive dust control efficiencies were also identified for specific types of devices and techniques.