Rock crushers –also called non-metallic mineral processing plants–are credited with a variety of environmental impacts: air pollution; ground and surface water contamination; solid and hazardous wastes; increased traffic to and from mining sites; and scenic degradation. As a consequence of these impacts, rock crushing plants in the United States are subject to federal, state and local environmental laws and permitting requirements.
Air pollution from dust (also called particulate matter) is the No. 1 environmental impact of rock crushers. Minute particles of dust–10 microns (.0004 inches or .01 mm) or less in diameter, called PM10–can damage the lungs. Dust from rock crushing facilities can coat nearby residential and office buildings.
Under the authority of the Clean Air Act, the U.S. Environmental Protection Agency (EPA) requires certain rock crushers to comply with the New Source Performance Standards (NSPS) regulation. The EPA has granted authority to some states to administer NSPS locally. There may be additional federal, state and local air quality requirements. The best way to obtain information about these is to call the local environmental agency office.
Ground and Surface Water Contamination
Another important environmental impact of rock crushers is water pollution from sediment runoff, particularly in temperate climate zones. Excess sediment clogs streams, causes flooding and harms fish; sediment runoff into storm water sewer systems can also cause problems.
In drier climates, where groundwater is in short supply, the quantity of water necessary for rock crushers to wash equipment and control dust may strain the local water supply. The National Pollutant Elimination Discharge System (NPDES) program regulates water pollution from rock crushers.
Solid and Hazardous Wastes
Like all manufacturers, rock crushers produce solid waste, for which a suitable disposal method must be found. Rock crushers may also produce hazardous wastes as a product or by-product of the processing of raw material. Both solid and hazardous wastes must be disposed of according to guidelines supplied by the federal Resource Conservation and Recovery Act (RCRA), to minimize their impact to communities and the environment.
Rock crushers can result in a significant increase in traffic and hazardous conditions for motorists on highways, as trucks filled with gravel or other material, often uncovered or loosely covered, enter and leave the processing plants many times per day. This increases the quantity of airborne particulate matter (dust), diesel exhaust fumes and other air pollutants in and around the vicinity of the plants.
Rock crushers can destroy scenic views in areas where mining facilities abound, such as occurs around some large cities in New Mexico, as noted in a 2004 study by the Center for Science in Public Participation.
Other ambient impacts from rock crushers include bright lights from facilities that operate at night and loud noises from equipment operation that can be heard up to a mile away.