PERMFILE122690

• Permit No: C1994082
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Doc Name: ASSUMPTIONS VALUES AND CALCULATIONS USED TO ASSESS WATER QUALITY IMPACTS FROM RESATU
• Section_Exhibit Name: TAB 17 ATTACHMENT 17-5
• Media Type: D
• Archive: No

3. Saturated thickness determined for premining alluvium along Annand Drew (YAAL[4 ),

Grassy Creek (YGAL 11i, YGAL15 ), and Sage Creek (YSAL1) were obtained from Table 7-4, •
Teb 7. Saturated thickness for Well GW-33A was calculated to be 35.7 feet.
Saturated thickness for Y-1 tributary alluvium was based on proportioning saturated
thickness et YGAL17 by the ratio of alluvial widths between the two locations (.40).
Estimates of saturated alluvial widths were obtained from Exhibit 16-3, Tab 16.
4. xydraulie gradients in the alluvium were determined by considering local gradients
using proximate, up- or downgredient alluvial well water level data. Hydraulic
gradients for the Annand Dr~3w alluvium (YAAL14) and Y-1 Tributary alluvium were
assumed to be equivalent to the proximate stream channel gradients.
5. Hydraulic conductivities were based on site-specific aquifer tests performed in
alluvium. Hydraulic conductivity for lower Grassy Creek Well GW-33A (downgradient of
Seneca II Mine) ossumed similar to value determined for YGAL15. Hydraulic
conductivity for Y-1 Tributary alluvium Bssumed to be similar to K determined at Well
YAAL14.
b. Alluvial mean TDS values were caLcul aced using TDS measurements obtained et
monitoring cells during the June through September growing season. Data for alluvial
Well GW-33A was obtained from the Seneca !I PAP and Seneca 11 Annual Hydrological

Re
orts (ANR
1993)
1992
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ll YGAL17
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ar to
Y-1 Tributary alluvium.
7. Discharge of resaturated spoil into the immediate downgradient alluvium (Annand Draw,
011 Tributary (YGAL16), Y-1 Tributary) calculated by estimating the additional
saturated thickness expected due to infiltration of spoil discharge, and holding
width, I and A constant. Additional saturated thickness (infiltration) for Annand
Drew (YAAL14, 3 ft) and 011 Tributary alluvium (YGAL16, 3 ft) estimated by averaging
water level rises measured during the spring snowmelt period (Appendix 7-2, Tab 7)-
Additional saturated thickness (infiltration) for Y-1 Tributary alluvium assumed to
be similar to water level rises measured at Well YGAL17.
•
17-5-4 Revised 06/19/95