Aggregate – sand, gravel, and crushed stone – is the number one non-fuel mineral resource in the United States and the World in terms of volume and value. Every developed and developing country produces aggregate. In the United States, there are nearly 10,000 active pits and quarries. It is becoming increasingly difficult to mine aggregate due to conflicting land uses, zoning, citizen opposition, inability to obtain permits, and environmental issues. Nevertheless, it is estimated that more aggregate will need to be produced during the next 25 years than has been mined during the previous 100 years. Extracting aggregate resources causes environmental impacts, most of which are relatively benign. Aggregate extraction seldom produces acidic drainage that may be associated with mining of metallic or energy resources. Other serious environmental health hazards are rare. Some environmental impacts from aggregate extraction are engineering-related. The most obvious impacts are the physical and visual changes to the landscape. These impacts can be accompanied by loss of habitat, blasting effects, noise, dust, erosion, and sedimentation. There is a concern about health impacts associated with crystalline silica and naturally occurring asbestos in dust generated during aggregate extraction and processing. Some geologic environments, such as active stream channels, karst areas, and ground-water systems in general, are dynamic and respond rapidly to outside stimuli. In these environments aggregate mining can alter the dynamic equilibrium of the area resulting in cascading environmental impacts. Most environmental impacts associated with aggregate extraction can be identified and assessed utilizing systems analysis and risk analysis techniques, and can be controlled or kept at tolerable levels by employing best practice environmental management. Failure to adequately address environmental issues can lead to serious, long-lasting, and irreversible environmental consequences, either in the vicinity of the site or at locations distant from the site.