Draft Environmental Impact Statement for Roca Honda Mine

Chapter 3. Affected Environment and Environmental Consequences
Several small pools of water apparently gather along some of the drainages off Jesus Mesa. These
may support small communities of wetland plants, indicating that they are moist much of the
year. Species present include scratchgrass (Sporobolus contractus), mesa dropseed (S. flexuosus),
straw-color flat-sedge (Cyperus strigosus), sand dropseed, rush (Juncus sp.), pale spikerush
(Eleocharis macrostachya), and even cattail (Typha domingensis).
The drainages on the west and north sides of Jesus Mesa have sandier soils and support desert
grassland. In these drainages the most common plants are hairy and blue grama, rubber
rabbitbrush (Ericameria nauseosa var. graveolens), and sage (Salvia prob. incisa). There are
occasional stabilized and semistabilized sand dunes throughout the permit area, especially to the
west, northwest, and southeast of the mesa. These areas support a variety of sand-dependent
plants, including sandhill muhly (Muhlenbergia pungens), spectacle pod, sand sage (Artemisia
filifolia), spiderwort, Bigelow’s rubber rabbitbrush (Ericameria nauseosa var. bigelovii), kiss-mequick,
and field wormwood (RHR, 2009d).
In Section 16, desert grassland and very open piñon-juniper woodland communities dominate.
The largest drainage basin begins at the base of Jesus Mesa and runs south-southwest. Smaller
drainages generally run southeast from the highest point in Section 16 on unnamed mesa at 7,292
ft elevation (mesa 7292). On both the west and east sides of mesa 7292, drainages are found with
steep slopes and cliffs up to 50 feet in height.
The area east of mesa 7292 is grazed desert grassland. The dominant grasses are hairy and blue
grama, with several areas of ring muhly (Muhlenbergia torreyi); however, much of the area is
dominated by carpets of garden purslane with other annuals in abundance. The most plentiful of
these annuals are Colorado rubberweed (Hymenoxys richardsonii var. floribunda), wild potato
(Solanum jamesii), and both spotted and thyme-leaf spurge (Chamaesyce maculata and C.
serpyllifolia). Another plant found in abundance is dodder (Cuscuta sp.), which is apparently
parasitizing the garden purslane (RHR, 2009d).
The rest of the Roca Honda permit area is very open piñon-juniper woodland with areas of desert
grassland. Oneseed juniper is much more common than piñon, but is usually widely scattered.
There are very few understory shrubs, although flat sagebrush is common along the rims of the
mesas where there is more exposed bedrock. Cliffrose occurs occasionally along the drainages.
Garden purslane is quite common here, with kissme-quick replacing it in sandier areas. Colorado
four o’clock is common both under the Utah junipers and in the open.
There is one seasonal cattle pond in the center of Section 16. The dominant plants in this artificial
pond include Mexican fireweed (Kochia scoparia), Russian thistle (Salsola tragus), and golden
crownbeard (Verbesina encelioides), rubber rabbitbrush (Ericameria nauseosa var. graveolens),
saltcedar (Tamarix chinensis), and foxtail barley (Hordeum jubatum) (RHR, 2009d).
Vegetation Communities Along the
Proposed Water Reuse Pipeline Route
As related in chapters 1 and 2, RHR originally intended to discharge treated mine water into an
unnamed arroyo that is tributary to San Mateo Creek on the southern edge of the proposed surface
facilities within Section 16. However, concerns were expressed during and after scoping about the
potential for remobilization of toxic materials and radionuclides in tailings and alluvial sediments
downstream along San Mateo Creek in the vicinity of the Homestake Mining Company Mill
DEIS for Roca Honda Mine, Cibola National Forest 199