REV06625

• Permit No: C1980001
• IBM Index Class Name: Revision
• Doc Date: 1/9/1990
• Doc Name: EDNA MINE MID-TERM C-80-001
• From: MLRD
• To: JEFF CLAPTON
• Type & Sequence: MT2
• Media Type: D
• Archive: No

A ~•
III IIIIIIIIIIIII III
999
STATE OF COLORADO
MINED LAND RECLAMATION DIVISION oF.~o~
Department of Natural Resources F~7~
7313 Sherman Sf.. Room 215 t•~~`' F,1
Denver, CO 80203 C~~;J~7/
303 B66-3567 .,e ~bs
FAX: 303 832-B 106
Roy RomeG
(ioramor
Fretl R. Banta,
DATE: January 9, 1990 Division Deector
T0: Jeff Clap ton
FROM: Cathy Begej ~'~
RE: Edna Mine Mid-Term C-80-001
Does the drilling performed in 1984 and 1989 modify P & M's
representation of the piezanetric surface, as shown on Exhibit 2.5-11?
Please modify this map if appropriate.
Please update Section 2.2.4.1, Well Logs and Geophysical logs, with logs
obtained during exploration drilling programs and W.W.and L stability
studies during the past ten years. Then, plot the sites on Exhibit 2.1-2
and/or 2.5-2 as appropriate.
3. Prepare a table which summarizes completion data for wells in the
monitoring program. Identify the elevation of the top of the casing,
the total depth, the location of perforated casing, the casing diameter
and the casing canposition.
4. The proposed mining plan involves mining in the Oak Creek drainage
basin. Please modify the hydrologic monitoring plan to include surface
and ground water monitoring of Oak Creek and its alluvium to ensure that
the impacts to Oak Creek are as predicted.
The permit application identifies four aquifers; the Trout Creek
Sandstone, the Wadge coal seam, the overburden, and the alluvium of
Trout and Oak Creeks. Since the permit was written, consultants for
P & M have identified an aquifer in the lower coal. Prepare a monitoring
plan to identify impacts from mining in each of the identified aquifers.
Include a site which provides data from an undisturbed site in each of
the aquifers, a control, as well as sites which can be used to measure
those impacts predicted in the Probable Hydrologic Consequences section
and in the stability reports prepared by the consultants per Rules
2.05.6(3)(b)(iii) and 4.05.13(1)(a) and (b ). Monitoring shall be
adequate to plan for modification of surface mining activities if
necessary, to minimize disturbance of the prevailing hydrologic balance.
Please update Table 2.5-7 and Exhibit 2.5-11 to reflect any changes in
the adjudication file over the last nine years. Please modify the
listing to indicate the appropriate date assigned to each decree.