2012-03-07_HYDROLOGY - C1981033

• Permit No: C1981033
• IBM Index Class Name: Hydrology
• Doc Date: 3/7/2012
• Doc Name: Hillside Seep Memo
• From: Mike Boulay
• To: Sandra Brown
• Permit Index Doc Type: Correspondence
• Email Name: SB1
• Email Name: MPB
• Media Type: D
• Archive: No

STATE OF COLORADO
DIVISION OF RECLAMATION, MINING AND SAFETY
Department of Natural Resources
1313 Sherman St., Room 215
COLORADO
Denver, Colorado 80203
F
DIVISION O F
Phone: [phone]
RECLAMATION
FAX: [phone]
MINING
—
INTEROFFICE MEMORANDUM
SAFETY
John W. Hickenlooper
Governor
TO: Sandra Brown Mike King
n /� Executive Director
FROM: Mike Boulay !" 1� Loretta E. Pifieda
Director
DATE: March 7, 2012
SUBJECT: Hillside Seep at Bear No. 3 Mine
I have completed a review of mine files, project files and all other related information that is
available pertaining to the hillside seep that discharges from the toe of the hill slope located
above the Bear No. 3 Mine yard. The spring has flowed continually since November 17, 1997
and is postulated to issue from the backfilled portal of the abandoned Edwards B -seam coal mine
that operated in the same locale prior to the Bear Mine. This memo presents an analysis of the
water quality of the spring discharge and discusses potential impacts to the hydrologic balance.
My conclusions regarding the water source for the seep are given and recommendations for
future conveyance of the discharge are provided. A general overview of mining in the region,
site characteristics and pertinent information related to the seep development are described in the
Background section below.
Background
Based upon review of all available permit documents the following summary is provided. The
Bear No. 3 Mine was developed within a historic coal mining area. The Bear No. 3 facilities are
located one - quarter mile east of the town of Somerset, Colorado adjacent to the North Fork of
the Gunnison River. The area upslope and to the south of the Bear No. 3 Mine has been mined
extensively in the past. The coal mined from Bear No. 3 is located in the Somerset coal field.
The North Fork of the Gunnison River has cut a deep canyon across the northern part of the coal
field. Coal mined from this location is from the coal- bearing Mesaverde Formation of Upper
Cretaceous Age. Specifically the B and C Seams of the Lower Coal Member of the Mesaverde
Formation were mined. See Attachment 1 Generalized Stratigraphic Column taken from the
Bear Mine permit document for reference. The B and C Seams outcrop on the hillside slope
above the Bear Mine yard and this is where portal entries were established as described further
below. The dip of the coal seams is to the northeast at generally less than 5 degrees. Mining was
accomplished in the up -dip direction to the south, so theoretically any groundwater or mine
inflows encountered would drain back to the portal entry toward the outcrop and North Fork of
the Gunnison River. The level of the North Fork of the Gunnison River is about fifteen feet
below the B -seam outcrop and roughly 65 feet below the C -seam.
Office of Office of
Mined Land Reclamation Denver • Grand function • Durango Active and Inactive Mines