1988-04-11_PERMIT FILE - C1981008A ‎(15)‎

• Permit No: C1981008A
• IBM Index Class Name: PERMIT FILE
• Doc Date: 4/11/1988
• Doc Name: Probable Hydrologic Consequences
• Section_Exhibit Name: Tab 17
• Media Type: D
• Archive: Yes

Mine Plan. An average daily ground water inflow of 5,229 ft3/day was calculated for year
5. To assess the impact of this inflow on Calamity Draw and the San Miguel water quality
during mining, it was assumed that the entire flow was discharged into Calamity Draw and
the San Miguel River and that the TDS level for the overburden aquifer was representative
of the chemical load. Tables 17-5A and 17-58 show the water quality impact computations
for Calamity Draw and the San Miguel River, respectively. The computations are based on
equations presented by Ferreira (1984) and are explained in detail in the section of this
Tab on "Potential Impact of Replaced Spoils on Surface Water Quality". The duration of
the water quality impacts is relatively short term (5 years) and the significance of the
impact is negligible as TDS increases in the range of only .08 to 1.5 percent are
projected. These projected changes in TDS levels will in no way affect the present and
potential uses of the surface water and are so small that they will not be measurable.
Water quality impacts to Tuttle Draw and the San Miguel River at its confluence with
Tuttle Draw are addressed in the section on "Potential Impact of Replaced Spoils on
Surface Water Quality" as pumpage of ground water inflow at the Nucla mining area is not
necessary.
Impact of Spoil Water Quality on the Ground and Surface Water Quality.
Introduction. This Tab contains a determination of the Probable Hydrologic Consequences
of the existing and proposed mining plan on the quantity and quality of surface and ground
water in the permit and adjacent areas. The following discussion is divided into six
sections. They are as follows: 1) overburden, interburden and underburden
characterization; 2) the controls on ground water quality, including mechanisms for the
production of acid, mineralogy and neutralization potential; 3) geochemical modeling; 4)
the effects of irrigation on the ground and surface water chemistry; 5) potential impacts
of replaced spoil on ground water quality; and 6) potential impacts of replaced spoil on
surface water quality.
Regional and site-specific geologic and hydrologic data were collected and analyzed to
assess the effects of mining on the potential contamination and diminution of ground and
surface waters; the presence of acid-forming or toxic-forming materials and their effect
on ground and surface waters; the downstream availability and quality of water which is
used for domestic, agricultural, industrial or any other such purpose; and the potential
impacts to the hydrologic balance. The study area includes the Nucla and Nucla East
mining areas and the surrounding region bounded to the south and west by the San Miguel
17-30 Revised 04/11/88