REP43740

• Permit No: C1980007
• IBM Index Class Name: Report
• Doc Date: 6/3/1996
• Doc Name: B East Mains Mine inflow report
• From: MOUNTAIN COAL CO
• To: DMG
• Permit Index Doc Type: MINE INFLOW REPORTS
• Media Type: D
• Archive: No

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Mountain Coal Company
West Elk Mina
Poet Office Box 591
Someroet, Colorsdo 81434
Telephone [phone]
Fax [phone]
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May 29, 1996
Mr. David Berry
Mr. Mike Boulay
DIVISION OF MINERALS AND GEOLOGY
Office of Mined Land Reclamation
1313 Sherman Street, Room 215
Denver, CO 80203
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Re: West Elk Mine, Permit No. C-80-007, B East Mains Inflow Summary of Events
Dear Dave & Mlke:
As you know Mountain Coal Company (MCC) experienced a large inflow of water in the fifth
entry of the B East Mains upon mining through a faulUfracture between cross-cuts #17 and #18
on March 16, 1996 (refer to attached map.) The inflow was estimated at approximately 350 gpm
initially, increasing to a maximum of approximately 800 gpm from the roof and floor within 48
hours (see graph attached.) The fault area, a series of small faults oriented in a N60°E duection,
was initially encountered in the sixth entry between cross-cuts #16 and #17, but contained little
water. MCC had not observed the fault nor water in previous exploration in the area, nor from
lineament or other geotechnical evaluations of the surface lands.
The water from the fault was measured at 83~'. Lab analysis showed that the water is typical of
other "bedrock water" obtained from MCC's B-seam monitoring wells (e.g., JMB-12). The
water was slightly alkaline, contains sodium bicarbonate, and exhibits higher conductivities and
TDS (i.e., >2,000 µmhos/cm and >1,500 mg/L, respectively) than surface or shallow,
colluvia!/alluvial ground water (see analysis results attached). A brief review of past drilling
records also showed some down hole temperatures measured at 75'F to 85~'.
MCC worked to quickly contain and control the inflow for the safety of our miners and to restore
mining in the section. Pumps and piping were installed to discharge the flows from the mine. All
discharges from the mine were contained and treated (settled) in ponds MB-1 and MB-2R and
released in accordance with CDPS permit parameters.
On Apri108, 1996, MCC encountered the same fault in the fourth entry (the next entry to the
north). No water was observed through the mining and subsequent roof bolting cycle in this
entry. Approximately 30 minutes later, a block of coal, approximately 5' wide by 6' long, lifted
from the floor and water "gushed up" from the floor about two feet high. Based on the pumps