1995-09-29_REVISION - M1977493

• Permit No: M1977493
• IBM Index Class Name: REVISION
• Doc Date: 9/29/1995
• Doc Name: Ground Water Monitoring Plan
• From: Climax
• To: DRMS
• Type & Sequence: AM6
• Media Type: D
• Archive: No

r
s + S
y
the upper end of Tenmile Creek valley, while the tailing impoundments are located in the
Tenmile Creek valley and the Eagle River Valley. A plan map of the mine site is presented in
• Figure 1. _
The Tenmile Creek, the East Fork of the Arkansas River, and the East Fork of the Eagle River
are inhabited by naturally reproducing and self-sustaining trout populations (Aquatics
Associates, 1994). In addition these watersheds support extensive macroinvertebrate
communities. Terrestrial ecosystems have been identified and are incorporated into the Climax
Reclamation Permit (Climax Molybdenum Co., 1977).
There are no users of ground water within four miles of Climax and thus the only beneficial use
of ground water in the vicinity of Climax Mine is for surface water recharge.
Site Geoloav
Climax Mine is located in the Mosquito-Tenmile Range of the southern Rocky Mountain
Cordillera. The ore bodies are hosted by two Precambrian rock formations, the Idaho Springs
Formation, and the Silver Plume Granite. The Idaho Springs Formation is a meta-sedimentary
rock, metamorphosed 1.7 billion years ago during a period of major geologic activity. Its major
components are biotite schist and gneiss. Silver Plume Granite occurs in stocks, dikes and sills
that intruded the Idaho Springs Formation approximately 1.4 billion years ago. These two
formations also are intruded, to a lesser degree, by early Tertiary diorite porphyry and quartz
monzonite approximately 60 million years old.
The Climax ore bodies lie just east of the Mosquito Fault, an important local structure that
• trends roughly north-south, and that dips approximately 60 degrees to the west. The fault, as
shown on Figure 1, runs north-northeastward across the Tenmile Creek valley over a distance
of approximately 30 miles. The Mosquito Fault presents a discontinuity between the
Precambrian bedrock on the east with the Paleozoic and Tertiary bedrock on the west.
Location and Description of classified stream segments
Arkansas segment 1 b, mainstream of the East Fork of the Arkansas River from the source to a
point immediately above the confluence above Birds' Eye Gulch, is classified as Aquatic Life
Cold 1 and Recreation 2.
The mainstream of the Eagle River from the source to the compressor house bridge at Bolden
is classified as Aquatic Life Cold 1, Recreation 1, Water Supply, and Agriculture.
The mainstream of Tenmile Creek below the Climax Parshall Flume in segment 13 is classified
as Aquatic Life Cold 2, Recreation 2, and Agriculture.
Site Hydrogeoloav
Ground water in the vicinity of the Climax mine site is generally present within a thin veneer of
alluvium and glacial till overlaying the bedrock, and ranges from near ground surface to a few
tens of feet below ground surface. Ground water occurrence within the bedrock is limited to the
upper fractured portion of the bedrock units. A hydrogeologic study of the underground
• workings (Titan, 1994) indicated that the bulk permeability of the bedrock is relatively low and
that the bedrock is not capable of transporting significant quantities of ground water.