APPCOR10035

• Permit No: C1981032
• IBM Index Class Name: Application Correspondence
• Doc Date: 12/15/1980
• Doc Name: HYDROLOGIC MONITORING OF CURTIS CREEK
• From: NORTHERN COAL CO
• To: MLRD
• Media Type: D
• Archive: No

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Suite 200, 740 So. Cobratlo BNtl.
P. 0. Boi 17583, Terminal Annn
Denver, Cobrado 80217
Tekphone 303753-BfiOD
December 11, 1980
Northern
Coal
Company
Mr. Jim Herron
Colorado Division of Mined Land Reclamation
723 Centennial Building
1313 Sherman Street
Denver, Colorado 80203
RE: Hydrologic Monitoring of Curtis Creek
Dear Mr. Herron:
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We have been reviewing the hydrologic situation relative to mining
under Curtis Creek and have developed a program for hydrologic and
subsidence monitoring which we feel will satisfy your requests.
First, I would like to outline what we perceive to be, as a result
of our meeting with the CMLR staff, the four primary issues to be
addressed in this monitoring program. They are: (1) subsidence
monitoring; (2) monitoring of volume of water encountered in the
mine; (3) surface water flow monitoring above the subject area; and,
(4) ground water monitoring. I would like to take each of these
issues and discuss in detail why it is important and how Northern
intends to address each particular monitoring parameter.
I. Subsidence Monitoring
As we have stated earlier, initially four main entries will be
advanced to the east under State Highway 13 and Curtis Creek.
The main entries will be used to transport people and materials
for the life of the mine. In order to maintain the integrity
of the entries, large barrier pillars will be left on either
side of the main entries. In a normal situation, main entry
pillars would be removed after mining is completed as the equip-
ment is pulled from the mine. However, in this instance, in
order to insure that the geologic structure underlying Curtis
Creek is not altered, pillars will not be removed under Curtis
Creek or State Highway 13/789. (See attached map ME-7960-10-1/2
which depicts the location of pillars under Curtis Creek and
State Highway 13/789.)
The concept of leaving the pillars in place under Curtis Creek
and the highway will insure that no subsidence will occur in
this area which will adversely affect either Curtis Creek or
the State Highway. In order to monitor for even the slightest