Environmental Geology (1994) 23:221-227 9 Springer-Verlag 1994 R. Poulin - R. C. Pakalnis 9 K. Sinding Aggregate resources: Production and environmental constraints Received: 2 June 1993 / Accepted: 25 October 1993 Abstract Aggregates are produced from sand and gravel deposits or from bedrock sources. Production sites are numerous to minimize transport and are more and more in a competing land use position. Urbanization, while creating a market, also sterilizes deposits and pressures producers to relocate further from populated areas. Regu- lating and permitting quarries is an issue in regions with growing populations. This regulatory environment may cause exploitation schemes to evolve towards greater re- cycling, importing, and marine production, for example. These changes may be entirely attributable to increased environmental constraints on producing operations and not on conventional mining constraints such as overbur- den, ore grade, and costs of operation. Key words Construction material -- Sand -- Gravel -- Crushed stone -- Non-renewable resource -- Mineral production Introduction Crushed stone together with sand and gravel constitute the two main sources of natural aggregates, the vast majority of which are used in the construction industry. Together they constitute the largest, by tonnage, nonfuel mineral commodities currently produced in North America. The freight on board (f.o.b.) value of the reported United States production of aggregates in 1991 exceeds US$7.7 billion. Further exploitation of this type of resource, however, has been significantly restricted because of increasing ur- banization and growing public concerns with environmen- tal issues (Thomson 1980). The growth of populated areas has put a strain on aggregate producers who are required R. Poulin (1~1) 9 R. C. Pakalnis - K. Sinding Department of Mining and Mineral Process Engineering, University of British Columbia, Room 517, 6350 Stores Road, Vancouver, British Columbia V6T 1Z4, Canada to maintain supply while being inconspicuous. Economic constraints require that quarry sites and their related pro- ducing facilities be located in or near population centers. Herein lies the paradox of this industry: a constant, pre- dictable need for products and the community's desire that mining operations be conducted far from its boundaries (Carter 1975). A logical alternative is sequential land use (Patty and Wongsosentono 1987), such as resource extrac- tion before the land is removed from the mineral base and used for other purposes. This, however, requires planning of aggregate extraction and establishing a quarry-permit- ting mechanism that can generate consensus. Aggregate Aggregate is an industrial material that is simultaneously low in value, high in bulk, and abundant. It is nearly omnipresent but not always available near major demand centers. The industry is characterized by a large number of operations of variable size. Occurences of aggregate resources Most hard rocks are potentially useful for coarse aggre- gate, but, because of the variety of specifications and uses, some specific qualities must be present in the source mate- rial. It may often be taken as a working rule that a rock with a water absorption value of less than about 2 percent will usually produce a good quality aggregate and that rocks with values exceeding about 4 percent may not (Collis and Fox 1985). Sand and gravel deposits are accumulations of the more durable rock fragments and mineral grains. The principal sources for sand and gravel, from a geological viewpoint, are active or ancient river systems and glaciated terrains (Fig. 1). Deposits that yield sand and/or gravel can be classified as stream deposits, alluvial fans, glacial, and fluvial-glacial deposits. The stream deposits can be subdi-