2010-04-16_PERMIT FILE - C1996083A ‎(10)‎

• Permit No: C1996083A
• IBM Index Class Name: Permit File
• Doc Date: 4/16/2010
• Doc Name: pg 2.05-59 to 2.05-126
• Section_Exhibit Name: 2.05 Operation and Reclamation Plans Part 2
• Media Type: D
• Archive: Yes

0 2.05.6
The predicted gob pile leachate, based on the Upper B -Seam roof and floor
analyses presented in Volume III, Tab 6, has an average iron concentration of 26.8
ppm and average manganese concentration of 1.9 ppm. The predicted coal pile
leachate based on the Upper B -Seam Coal analyses presented in Volume III, Tab 6,
has an average iron concentration of 8.6 ppm iron and average manganese
concentration of 0.1 ppm. The iron and manganese baseline values for the river are
obtained from the Bowie No. 2 Mine, 2006 annual hydrologic report, average from
lower monitoring point. The following table presents the impact gob pile leachate
and coal pile would have if it flowed into the river at the rate of 46.9 and 4.7 gallons
per minute respectively.
PHC North Fork of the Gunnsion River
C7
•
TR -64
A Mow- -b
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.
The predicted pH of the gob pile leachate and coal, based on the data presented in
Volume III, Tab 6, are 9.2 and 9.3 respectively. The North Fork of the Gunnison
River has pH values in the 8.3 range. If the entire 55.6 gpm of leachate entered the
River, the pH of the River would increase from 8.3 to 8.305 which is insignificant.
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 Mesaverde
Formation are available within the permit area, 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. 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 09/09
Flow gpm
Flow cfs
Iron (ppm)
Mn (ppm)
North Fork
11,220
25.00
0.21
0.09
Gob Leachate Discharge
50.9
0.11
26.8
1.9
Coal Pile Leachate
4.7
0.01
8.6
0.1
Combined Flow
11,275.61
25.121
0.331
0.098
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.
The predicted pH of the gob pile leachate and coal, based on the data presented in
Volume III, Tab 6, are 9.2 and 9.3 respectively. The North Fork of the Gunnison
River has pH values in the 8.3 range. If the entire 55.6 gpm of leachate entered the
River, the pH of the River would increase from 8.3 to 8.305 which is insignificant.
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 Mesaverde
Formation are available within the permit area, 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. 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 09/09