Page 40 - Materials Chemistry, Second Edition

CAT3525_C01.qxd 1/27/2005 10:54 AM Page 11
Introduction 11
both President Bush and the U.S. Senate to serve as the nation’s high-level nuclear waste repository
(New York Times, 2002a, 2002b). Legal and political battles continue over this decision, however.
Low-level radioactive wastes comprise many diverse materials generated from industrial,
research, educational, and other processes. Sources include private and government laboratories,
industry, hospitals, and educational and research institutions. The Nuclear Regulatory Commission
(NRC) defines low-level radioactive waste as radioactive material that (10 CFR Part 62):
1. is not high-level radioactive waste, spent nuclear fuel, or by-product material as defined
in the Atomic Energy Act of 1954 (42 U.S.C. 2014(e)(2)); and
2. the NRC, consistent with existing law and in accordance with 10 CFR Part 61, classifies
as low-level radioactive waste.

Low-level radioactive wastes consist of trash and other materials that have come into contact
with radioactive materials, and may have become measurably radioactive themselves. Such wastes
include cleanup items like mops and rags, lab gloves, protective clothing, filters, syringes, tubing,
and machinery. Hundreds of different radionuclides can occur in low-level waste (Tammemagi,
1999). Approximately two million cubic feet of low-level radioactive wastes are disposed at com-
mercial disposal sites annually (Liu and Liptak, 2000).
Several techniques are available for the disposal of low-level radioactive wastes. In the
United.States, some wastes are buried in trenches situated in thick clay formations. Some are per-
mitted for disposal in a Subtitle D sanitary landfill. In France, low-level wastes are stored in heav-
ily reinforced concrete vaults (Tammemagi, 1999).

1.2.8 MINING WASTE
Mine waste includes the soil or overburden rock generated during the physical removal of a desired
resource (coal, precious metals, etc.) from the subsurface. Mine waste also includes the tailings or
spoils that are produced during the processing of minerals, such as by smelting operations. In addi-
tion, heap wastes are produced when precious metals such as gold, silver, or copper are recovered
from piles of low-grade waste rock or tailings by spraying with acid or cyanide solutions.
In mining operations, overburden wastes and tailings are returned to the surrounding environs
(Figure 1.4). Due to the enactment of federal and state mining reclamation laws—for example the

FIGURE 1.4 Mining wastes are typically returned to the site of operation.