REP37770

• Permit No: C1981038
• IBM Index Class Name: Report
• Doc Date: 3/19/1993
• Doc Name: MEMO CONCERNS OR ISSUES GENERATED FROM 1991 AHR INFLOW SUSIDENCE REPORT REVIEW
• From: DMG
• To: ORHCARD VALLEY AHR FILE C-81-038
• Permit Index Doc Type: HYDROLOGY REPORT
• Media Type: D
• Archive: No

• • III IIIIIIIIIIIIIIII
.STATE OF COLGw--w~
DIVISION OF MINERALS AND GEOLOGY
Department of Natural Resources
131; Sherman SL, Room 215
Denver, CO AO203
Phone. [phone]
FA%: (3031 8 32-8106
Memo to File
Date: March 19, 1993
To: Orchard Valley AHR File, C-81-038
From: Kent Gorham
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Rov Romer
Governor
LLChael B. I ung
Divieun Director
Re: Concerns or issues generated from 1991 AHR/Inflow/Subsidence Report Review
I have completed review of the above reports. COVCC will be submitting a technical
revision soon to reduce their monitoring program. My thoughts are as follows:
1. Any plan should be developed to be comprehensive for the next permit term. Areas
not to be mined can ,for the most part, be discontinued with conditions that they
will be revisited later. The water monitoring plan should be integrated with the
subsidence monitoring or control plan.
2. The three wells at the loadout should be checked quarterly for field and one well
should be sampled full suite annually.
3. The aquifer below the mine workings should be monitored using at least one well
downgradient.
4. Water users and water rights need to be factored into the reduction of the water
monitoring plan.
5. Water quality in ponds is meaningless.
6. Flow and field parameters in springs should be monitored regardless of being year-
round springs. After all, how did the name "spring" come about? This applies only
to those springs within or adjacent to affected areas.
7. Spring 18-5 should be monitored.
8. Annual verification of well depth shall be included in the monitoring requirements.
9. Springs or ponds over subsided or affected areas need to be monitored until they
have returned to their average historic condition.
10. Precipitation data (annual) needs to be reported over the period of baseline
collection through the current water year.
KAG/bjw
m:\oss\bjw\kep.memo