Draft Environmental Impact Statement for Roca Honda Mine

Chapter 2. Alternatives, Including the Proposed Action
fumes. Carbon monoxide and diesel fumes would be generated by mechanized equipment used
within the mine to extract ore. Radioactive radon gas, one of the “daughter products” in the decay
sequence of U-238 (the most abundant form or isotope of uranium), would be generated by the
mine itself as the uranium-bearing rock in the formation is exposed to air when the working faces
are opened up in the mine.
RHR is proposing construction of up to five
ventilation shafts approximately 9 feet in
diameter to facilitate effective mine ventilation
at the Roca Honda Mine. Final configuration
and location is subject to change depending on
conditions encountered at the time of operations.
Three of these ventilation shafts are proposed to
be constructed in the southeast quarter of
Section 9, and two are proposed to be
constructed in the northwest and southeast
quarters of Section 10.
Secondary escape routes are also critical to
facilitate safe underground mining. These
secondary escape routes provide a means for
workers to escape from the mine in the event of
an incident that disabled the production shaft or
prevented underground access to the production
shaft. Some ventilation shafts would also be
designed for use as secondary escape ways.
Ancillary Surface Facilities
Additional ancillary surface facilities are proposed to support the underground mine operation
such as:
• Haul and access roads
• Head frames, hoists, and ventilation shafts
• Soil stockpiles, rock stockpiles, ore pads, and nonore stockpiles
• Fuel, chemical, explosives, and equipment storage areas
• Drill pads to support development drilling and monitoring well construction
• Utility lines, pipelines, storm water control facilities, and fencing.
Radon
Radon is a naturally occurring element with the
symbol Rn and an atomic number of 86. The
atomic number refers to the number of protons in
the nucleus of every atom of a given element.
Radon is produced in soil, rock, and water by the
natural (radioactive) breakdown, or decay, of two
other naturally occurring chemical elements –
namely uranium, with an atomic number of 92,
and thorium, atomic weight 90.
Rn is a radioactive, colorless, odorless, and
tasteless gas. The most stable isotope of radon,
Rn-222, has a half-life of 3.8 days, after which
half of the original amount has disintegrated into
yet another element of the U-238 decay chain,
polonium, through radioactive decay, in this case
alpha decay (emission of a helium nucleus).
Radon is estimated to cause about 21,000 lung
cancer deaths per year, and is the second-leading
cause of lung cancer after smoking (EPA, 2010).
These facilities would be constructed during the development phase starting with facilities in
Section 16 and proceeding to facilities in sections 9 and 10. Major ancillary surface facilities are
planned to be constructed in the north half of Section 16 and the southeast quarter of Section 10.
A series of haul roads, mine access roads, and ventilation shaft access roads are proposed to
support the mining operation.
42 DEIS for Roca Honda Mine, Cibola National Forest