9.1.2 Processing Stone Processing activities include conveying, screening, secondary and tertiary crushing, and sizing. Screening is the single most important part of the processing cycle of crushed stone particles. A wide variety of screen types exist, and their selection is a function of the material processed and the final product required.

revised AP-42 Section 11.19.2 on crushed stone processing and pulverized mineral processing. Emission data from nine emission tests conducted at stone (granite and limestone) processing plants were used to develop emission factors for various crushing, screening, and conveying operations. Descriptions of these

Pulverized mineral processing operations share the same extractive, crushing, and screening processing operation with crushed stone plants. Pulverized mineral operations continue to process the material to produce materials having an extremely small particle size distribution.

McLanahan designs and manufactures equipment that can be used in all steps of the production of construction aggregates, from crushing the material to the desired size and sorting the various sizes for specific uses, to maximizing …

 — AP 42 Section 11.19.2 Crushed Stone Processing and Pulverized Mineral Processing - Response to Comments. The information in this document has been funded by the National Stone, Sand and Gravel Association (NSSGA) for the U.S. Environmental Protection Agency (EPA).

Selected producers of crushed stone were surveyed on their attitudes to­ ward setting up structured quality control systems that might largely re­ place much of the conventional testing of aggregates by state inspectors.

The test was conducted at the Wake Stone Corporation stone crushing facility located in Knightdale, North Carolina, which produces crushed granite for construction and road projects.

In HICs, the extraction of sand, gravel, and crushed stone is largely regulated, mechanized, and practiced by formal quarrying companies, with sand and gravel extraction from natural waterways comprising a minority of aggregate production.

Techniques used for extraction vary with the nature and location of the deposit. Processing operations may include crushing, screening, size classification, material handling, and storage operations. All of these processes can be significant sources of PM and PM-10 emissions if uncontrolled.

A variety of material, equipment, and operating factors can influence emissions from crushing. These factors include (1) stone type, (2) feed size and distribution, (3) moisture content, (4) throughput rate, (5) crusher type, (6) size reduction ratio, and (7) fines content.