very carefully. Acceptability of aggregates should be based on standard 
tests of the American Society for Testing and Materials. An investi- 
gation of a source for aggregates should be thorough and make certain 
any supply of acceptable aggregates is adequate for the amount of 
concrete required. It is quite probable that some existing source of 
aggregates already processed and ready for use will be found. On the 
other hand the exigency of the situation may require development of 
an entirely new source of raw materials. In this case, a custom-built 
mining and processing plant will be required. A plant of this nature 
would be quite costly. It could be justified on the basis that there 
is no other alternative or that enough aggregates will be required to 
make the price of the product competitive with other sources of 
materials. 
To the best of the author's knowledge, data concerning amounts and 
locations of deposits of suitable concrete aggregates are not available. 
The following table showing sand and gravel production in the Pacific 
Coastal states provides an indication of the availability of aggregates; 
however, these are not necessarily all suitable for use in portland 
concrete. 
Sand and Gravel Production - Pacific Coast States 
Location 
California, short tons 116,125,000 | 124,655,000 
Washington, short tons 28,164,000 31,432,000 
Oregon, short tons 19,630,000 } 18,260,000 
Source: Separate Reprints from the 1968 U. S. Department 
of the Interior, Bureau of Mines Minerals Year- 
book. The Mineral Industry of California. 
(Washington), (Oregon). Includes names and 
addresses of principal producers of sand, gravel, 
and cement. 
The Pit and Quarry publications issues annually a Directory of 
Nonmetallic Minerals Industries. (Pit and Quarry, 1970). Producers 
are listed alphabetically with a geographical cross-reference section 
of plants so all existent sources of production are known. 
Manufactured lightweight aggregates are available and weight 
savings are sometimes very advantageous compared to conventional mined 
aggregates. A schematic diagram of a lightweight aggregate manufactur- 
ing plant is contained in the Rocklite Lightweight Concrete Reference 
Manual (Lightweight Processing Company Publication). Many technical 
details about lightweight aggregate and concrete made with this aggregate 
are also included. 
