PERMFILE55100

• Permit No: C1996083A
• IBM Index Class Name: Permit File
• Doc Date: 9/25/2003
• Doc Name: pages 2.05-59 through 2.05-116
• Section_Exhibit Name: Rule 2.05 Operation and Reclamation Part 2
• Media Type: D
• Archive: Yes

2.05.6
PHC North Fork of the Gunnsion River

r1
L J
PR-08
A PPRaVEt)
9~~ s/o.3
Flow m Flow cfs Iron m ~ Mn pp~
North Fork 11,220 25 0.37 0.016
Gob Leachate Dischar a 5.3 0.01 332 7.5
Coal Pile Leachate 4.7 0.01 9 1
Combined Flow 11,230 25.02 0.53 0.020
Based upon the above calculation, if leachate from the gob and coal piles reached
the North Fork of the Gunnison River, it will not have a significant impact on the
quality of water in the river. A full suite analysis of the alluvial wells will be obtained
twice per year to determine if the coal or gob pile leachate has an impact on the
water quality in the wells.
The predicted pH of the gob pile leachate ranges from 8.0 to 8.7 which should not
have an adverse effect on the North Fork of the Gunnison River which has pH
values in the 8.5 range. The one sample available to predict the pH of the coal
leachate is 9.1 which is a little high. However, based on the predicted low flow of
coal pile leachate (4.7 gpm) the high pH value should not adversely impact the river.
Flooded mine workings could also impact the water quality in the area. When the
mines are sealed they will slowly fill with water. Although no data for permeability
or transmissivity of the saturated portions of the coal bearing member of the
MesaverdeFormationareavailablewithinthepermitarea, the experience by others
(Brooks, 1983) suggests the Mesaverde Formation transmits little water. Therefore,
the abandoned mine workings would not be expected to transmit water to the
surrounding strata. The quality of the water in the flooded mine workings could be
similar to the water in old Oliver Mine No. 1 located east of Somerset, CO which
mined in the D-Seam in the 1940's and 1950's. This mine is discharging water that
is monitored by Oxbow Carbon & Minerals as spring 8. This "spring" water has a
conductivity in the range of 3,000 to 4,000 umhos/cm (ref. OCM 1994 Annual
Hydrologic Report}. The salinity characteristics of the Oliver No. 1 Mine discharge
are similar to the assumed quality of the mine water discharge presented above.
Based on the above discussion, if the mine workings fill with water and discharge
through the portals, the impact on the North Fork of the Gunnison River would be
less than or equal to the mine water discharge analysis presented above.
2.05 - 75i - 07/03