mineral deposits. Thus, mines can only be located in those few places where economically viable deposits were formed and discovered.
Many hardrock commodities are associated with magmatic and hydrothermal processes, which in turn, are associated with modern or ancient mountain belts. The abundant igneous rocks and associated hydrothermal systems and the mountainous or sparsely vegetated terrain make the West the location of most hardrock mines in the United States. Some of these same areas are also valued for aesthetic and cultural reasons, which creates potential for conflict among uses of the land. While society requires a healthy environment, it also requires sources of materials, many of which can be supplied only by mining.
The mining process consists of exploration, mine development, mining (extraction), mineral processing (beneficiation), and reclamation (including post-closure). The hardrock mining process is described in Chapter 1 and Appendix A. Each step from exploration through post-closure has the potential to cause environment impacts. In addition to the obvious disturbance of the land surface, mining may affect, to varying degrees, groundwater, surface water, aquatic biota, aquatic and terrestrial vegetation, wildlife, soils, air, and cultural resources. Actions based on environmental regulations may avoid, limit, control, or offset many of these potential impacts, but mining will, to some degree, always alter landscapes and environmental resources. Regulations intended to control and manage these alterations of the landscape and the environment in an acceptable way are generally in place and are updated as new technologies are developed to improve mineral extraction, to reclaim mined lands, and to limit environmental impacts. Therefore, the committee emphasizes that these potential impacts will not necessarily occur, and when they do, they will not occur with the same intensity in all cases. The potential environmental impacts of hardrock mining are discussed in Chapter 1 and Appendix B.
Hardrock mining operations in the United States are regulated by a complex set of federal and state laws and regulations intended to protect the environment (see Chapter 2). The scope and degree of regulation depends on the type and size of the mining operation; the kinds of land, water, and biological resources affected; the state in which the operation is located; the organization of the state and local permitting agencies; and the ways federal and state agencies implement relevant statutes and regulations. The basic statute for hardrock mining on federal lands is the General Mining Law of 1872. Land management direction is provided in the Federal Land Policy and