Draft Environmental Impact Statement for Roca Honda Mine

Chapter 3. Affected Environment and Environmental Consequences
As discussed under “Air Quality,” Federal law also regulates emissions of radon from uranium
mines. Thus, neither miners nor the nearest neighbors of the proposed mine are expected to be
subjected to dangerous exposures to radon gas and its decay products.
Historically, at some uranium mines, uranium milling occurred right at or close to the mine site
itself. Raw uranium ore was transported to the surface and was crushed at the mill into a fine sand
or powder. Uranium was then recovered or extracted using chemical processing (leaching) and
further concentrated into “yellowcake,” so called because of its yellowish color; yellowcake
consists of 70–90 percent percent uranium oxide (U308). The radioactive sand or powdery
residues from these processes are referred to as uranium tailings (USNRC, 2012c; USEPA,
2010c).
These tailings typically contain a number of radionuclides. Although the milling process extracts
approximately 95 percent of the uranium present in raw ores, the tailings still contain naturally
occurring radioactive elements or radionuclides, among them uranium, thorium, radium,
polonium, and radon. In addition, tailings typically contain certain chemically hazardous heavy
metals like arsenic (USEPA, 2010c).
The past use of these mine/mill tailings in homes, schools, roads, and as materials in other
construction created public radiation health hazards, or so-called legacy issues. Waste from
uranium mining and milling operations that closed before the mid-1970s are of particular concern
even today. In a number of cases, these mines remain unclaimed and the waste is still piled near
the mine. When the tailings are left exposed to weathering, both wind and water can transport
them offsite. If permitted to dry out, the radioactive sand or dust can be dispersed long distances
by the wind and deposited over large areas, contaminating both soils and water bodies, and
entering the food chain. Uranium tailings piles are also susceptible to erosion and seepage of
contaminants into surface water and groundwater (USEPA, 2010c). To avoid these problems, later
mines began storing tailings in large impoundments.
However, the actions and their consequences associated with these legacy issues are not part of
the proposed action and would not occur at the proposed Roca Honda Mine. Under this proposed
action, uranium ore would be blasted and hauled to the mine surface through the production shaft.
The ore, consisting of chunks of rock and rubble at this stage, would then be placed on the ore
pad for temporary storage until it is loaded onto a highway haul truck. The ore would then be
hauled from the mine on this covered truck using one of the haul roads to an existing public
highway. From there it would be transported to an as yet undetermined uranium mill at some
distance from the mine and possibly out of State. Milling would be under the jurisdiction of the
U.S. Nuclear Regulatory Commission (NRC) and its relevant statutes and regulations.
Management and disposal of milling wastes (tailings) would be regulated, and the public interest
and environment protected by the Uranium Mill Tailings Radiation Control Act of 1978
(UMTRCA). No crushing, processing, milling, or disposal of the raw uranium ore extracted at the
Roca Honda Mine would occur at the mine site and is not part of the plan of operations. As
described in chapter 2, nonore waste rock would be used to backfill mined-out spaces once all ore
and rock have been removed. No tailings would accumulate at the surface of the mine.
As described under the “Air Quality” section, during development, operation, and reclamation of
the mine fugitive dust emissions associated with surface disturbance (drilling, blasting, site
development, and other earth-moving activities) would be generated. Fugitive dust and exhaust
emissions from vehicles and equipment traveling over paved and unpaved (gravel) surfaces
272 DEIS for Roca Honda Mine, Cibola National Forest