PERMFILE130951

• Permit No: C1981022A
• IBM Index Class Name: Permit File
• Doc Date: 9/16/2005
• Section_Exhibit Name: 2.04 Environmental Resources
• Media Type: D
• Archive: Yes

Scrrim - 2.04.7
Analysis values indicate a neutral to moderately alkaline pH and low to moderately high EC and TDS
• values, with TSS and total iron and manganese values ranging from low to moderately high,
depending on flow conditions, az summarized by Table 2.04.7-T8, Ephemeral and Intermittent
Drainages Surface Water Quality Summary. Generally, the quality of intermittent and ephemeral
surface water flows u good in the mine permit and adjacent areas, with water quality degrading
somewhat (elevated TSS, TDS, iron, and Mn) due to high sediment levek during and immediately
following spring snowmelt runoff and major thunderstorm events.
Surface Water Rights and Use -Due to quality and yield considerations, surface water and
associated alluvial/colluvial units are the primary water supplysources in the area. In the mine perrnit
and adjacent areas, beneficial uses are limited to the North Fork of the Gunnison River, Thompson
Geek, and Hubbard Geek
Existing water rights documentation, az updated by the Colorado Division of Water Resources in
August 1997 and s~~~*+~~~ed in Table 2.04.7-T4, Water Rights Summary- Mute and Adjacent Areas,
indicates a total of twenty-one surface water rights in the mine and adjacent areas. Of the identified
surface water rights, az shown on the Surface Water Hydrology Map, (Map 2.04-M6); five are
associated with mine ponds used for drainage and sediment control and water for dust control; one is
associated with the Blue Ribbon Reservoir No.l; one a associated with an individual domestic water
supply (Walter Gallob HGT No.l); and the rert+~irirg rights are associated with irrigation ditches,
canals, and pipelines. As indicated by Table 2.04.7-T4, allocations for the identified surface water
rights range from 0.11 (Hawk's Nest Water Supply to 244 cfs (Blue Ribbon Reservoir No. 1).
Alternative Water Supply Information - OMI's ongoing and proposed future operations will not
result in contamination, diminution, or intemuption of surface or underground water sources which
are subject to beneficial use. The potential for contamination is addressed through operation of
• OMI's drainage and sediment control and mine water discharge systems, with all duchargea being
subject to and consistently meeting applicable CDPS effluent standards. The potential for diminution
or interruption is addressed through OMI's existing water rights and design and implementation of
controlled mine development and extraction. OMI's water supply withdrawal and use levels are well
within permined allocations under OMI's senior water rights. With mine water discharge, OMI is a
net contributor to flows in the North Fork of the Gunnison River. Additional details relative to the
potential for contamination, diminution, or interruption of water supplies is presented in Section
2.05.6(3), Protection of Hydrologic Balance.
2.04.8 -Climatology Information
This settion of the permit application describes general climatic conditions in the vicinity of the Mme
Pertnit and adjacent areas az a basis for understanding and evaluation of muting-related impacts and
development of appropriate operation, reclamation, and restoration plaits. Most of the informuion
presented in this section u based on historical recomis and information from the closest active
meteorological stations providing temperature, precipitation, and wind data. Because these stations
are located in reasonable proximity to the Mine Permit Area and local climatic conditions do not vary
significantly, this data provides a reasonable representation of site climatic conditions.
General Climatology and Environment
Because the mine area u close to the Continental Divide, climate in the mine area u strongly
influenced by both topography and regional weather patterns. Generally, warm moist air rrtazses from
the Gulf of Mexico moving to the northeazt drop much of their moisture on the southern mountains,
with limited moisture reaching the Grand and North Fork Valleys. These same air masses tend to
• deflect moist air masses from the Pacific to the north, resulting in the semi-arid clirrtate of this area.
During winter, the Pacific au masses are reinforced and deflected to the south by arctic air rttazses
from the north resulting in increased precipitation az snowfall in the area
PR04 2.04-78 Revised August 2000