APPCOR12906

• Permit No: C1980003
• IBM Index Class Name: Application Correspondence
• Doc Date: 11/23/1981
• Doc Name: PROPOSED DECISION AND FINDING OF COMPLIANCE & Letter
• Media Type: D
• Archive: No

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VI. Hydrologic Balance: (con't)
Total dissolved solids concentrations range from 1200 to 1510 mg/1 for the
springs. Waters containing 1500 mg/1 or greater of total dissolved solids
are considered substandard for irrigation according to the standards of
the Environmental Protection Agency and the National Academy of Science.
These waters would be poor for use in irrigation.
The Division requires that groundwater monitoring be continued through this
permit term. H-G Coal Company has agreed to a sampling frequency and list
of parameters for monitoring which was suggested by the Division. Details
of the groundwater monitoring program are in Section 2.05.6 of Volume I
of the application.
The operation is in compliance with the requirements of this section.
VII. Alluvial Valley Floors - Rules 2.06.8 and 4.24.
H-G Coal Company was requested during, the review to prepare and submit a
reconnaissance level alluvial valley floor study. The applicant responded
with the requested material. This alluvial valley floor study has been
submitted as an additional bound volume which is included with the application
and is on file with the Division (Alluvial Valley Floor Study, H-G
Coal Company Mine and Loadout Facility Near Hayden, Colorado, Bischop
Associates, Inc.) Although the Division does not wholly agree with the
study's conclusion that Dry Creek is not an alluvial valley floor near the
Loadout, the effect of the Loadout on this alluvial valley floor will be
minimal. This is discussed further in the follocaing section.
Alluvial Valley Floor Findings
1. Pursuant to Rule 2.06.8(5); the Division finds that the proposed surface
coal mining operations will not interrupt, discontinue, or preclude farming
on an alluvial valley floor.
Unconsolidated alluvial deposits mapped in Hayden and Dowden Gulches are
less than 10 acres in extent and are therefore not extensive enough to be
considered potential alluvial valley floors (see the AVF Preamble, Alluvial
Valley Floor Guidelines, Region V Office of Surface Mining, June 11, 1981).
Further, the only effects produced by the operation will be of an indirect
nature through surface or ground water effects. No part of the operations
will physically disturb any of the deposits as mapped.
Portions of Dry Creek have areas of unconsolidated alluvial deposits of
sufficient extent to be considered potential alluvial valley floors. In
general, however, Dry Creek does not experience sufficient flow to support
irrigated agriculture to any great degree, and most tooter used for irrigation
in Dry Creek is diverted from adjacent watersheds (see pages 17 and 18 of
the Alluvial Valley Floor Study).