HYDRO31322

• Permit No: C1980001
• IBM Index Class Name: Hydrology
• Doc Date: 6/6/2007
• Doc Name: Authorization to Discharge Under the Colo Discharge Permit System
• From: Department of Health Department
• To: DRMS
• Permit Index Doc Type: NPDES
• Media Type: D
• Archive: No

Pittsburg and Midway Coal Company Edna Mine Water Quality Assessment CO-0032638
Table A-3
TVS-Based Metals Water Quality Standards for CO-0032638
Based on the Table Value Standards Contained in the Colorado Department of Public Health
and Environment Water ualit Control Commission Re lotion 33
Calculated Using the Following Value for Hardness as CaC03: 400 mg/1
Parameter Zn Stream Water
_QualilySfdndard ,
" '-Formalk Used ~.;

C
d
D
1
d
ACllte
17
Ug/1 (1.128(ln(hardness))-3.828)]
[1.13667.0.041841n(hardness)][e
a
mium,
1SSO
Ve ChrOIDC 6.2 ug/1 [1.10167-0.041841n(hardness)][e (0.7852(In(hardness))-2.715)]
TnValentChrOmmm, Aeute 1773llg/1 e(0.819(ln(hardness)}F2.5736)
Dissolved Chronic 231 ug/1 e (0.819(ln(hardness))+0.5340)
HeXaValent ChrOmlllm, Acute 16 ug/1 Numeric standards provided, Tormula not applicable
D1SSO1Ved ChrOn1C 11 Ug/l Numeric standards provided, formula not applicable

Di
l
d
C ACUte 5~ Ug~l e (0.9422{lu(hardness))-1.7408)
opper,
sso
ve ChTOn1C 29 Ug/1 e (0.8545(In(hardness))-1.7428)

L
d
Di
l
d Aerate 281 Ug/1 [1.46203-O.1457121n(hardness)][e(1.273Qn(hardness)}1.46)]
ea
,
sso
ve ('hrOn1C 11 Ug/1 [1.46203-0.1457121n(hardness)][e(1~273(In(hardness))-4.705)]

M
Di
l
d ACUte 4738 ug/1 e(0,333I(In(hardness)}+6.4676}
anganese,
sso
ve ChrOri1C 2618 Ug/1 e(0.3331(ln(hardness))+5.8743)

Ni
l
Di
l
d
k ACiute 1513 Ug/1 e (0.846Qn(hardness)}+2.253)
c
e
,
sso
ve ChrOn1C 168 Ug/1 e (0.846(In(hardness))+0.0554)

l
i
i
l ACUte 18 Ug/1 Numeric standards provided, formula not applicable
en
um, D
sso
ved
Se
Chronic
4.6 ug/1
Numeric standards provided, formula not applicable

l
Sil
Di
d ACUte 22 Ug/1 ~z e(1,72(In(hardness))-6.52)
ver,
ve
sso C17rOn1C 0.81 Ug~l e(1.72(In(hardness))-10.51)

Di
Zi
l
d Acute 379 Ug~l e {0.8473(In{hardness)}t0.8618)
nc,
ve
sso Clll'OIDC 382 Ug/1 e (0.8473(In(hardness)}F0.8699)
To conduct an assessment of the ambient water quality in Trout Creek upstream of the Edna Mine
Outfall 007, data were gathered at the Edna Mine Water Quality station TR-A located on Trout
Creek, approximately one mile upstream from Outfall 007. Data were compiled for a period of
record from Apri12000 through October 2004. For other metal pazameters, a compazable watershed
was used in the absence of upstream or downstream data for Trout Creek. USGS Station Numbers
09244464 (Hubberson Gulch near Hayden, CO}and 09060500 (Rock Creek near Toponas, CO) are
deemed to be representative of upstream quality. For example, Hubberson Gulch flows through a
coal-mining region about I S miles west of the Edna Mine and Rock Creek has similar origins. These
watersheds aze comparable to the Trout Creek watershed and the in-stream hardnesses are similar.
The period of record for this station is March 1978 through May 1982. These data were combined to
Appendix A (wQn sr vers;on a-3 Fnst> Page 6 of 19 Last Revised September 2, 2005