PERMFILE114605

• Permit No: C1982056A
• IBM Index Class Name: Permit File
• Doc Date: 12/11/2001
• Section_Exhibit Name: 2.06 Special Categories of Mining
• Media Type: D
• Archive: Yes

Monitoring; Stations of Sites within [Ite conFluence area of the above creeks are listed below:
• Station 301 is located on Trout Creek upgradient of the conFluence with Middle Creek, Flow: 14-IG
cfs in summer; TDS: average 320 mg/I (Figure 33, AHR 1993; data sheets)
• Station 69 is located downgradient from the confluence of Middle Creek, but upgradient from the
confluence of Fish Creek. Flow: 5 cfs in summer; TDS: average 578 mg/I (Figure 33, AHR 1993;
data sheets)
• Site 1002 is located on Fish Creek and is the last site above the conFluence with Trout Creek. Water
in Fish Creek Flows through Site 16 and Site I15 before reaching Site 1002. Flow: 3.35 cfs in
summer; TDS: average 1828 mg/I (Table 3 this report).
The calculations used [o determine [he theoretical impact of each stream on total dissolved solid (TDS)
concentrations in Trout Creek are discussed below:
Trout Creek (TC) background (Site 301) combined with Middle Creek (MC) (Site 29):
(TC flow x TC TDS conc) + (MC flow x MC TDS conc) =Average TDS Concentration
(TC flow + MC flow)
The calculations used to determine the theoretical TDS concentration in Trout Creek at site 1005 downstream from
the confluence of Trout Creek and Fish Creek are as follows:
(S.Ocjs x 433mg / L) + (3.35cjs x 1,828mg / L) -
- Average TDS Concentration = 922mg / L TDS Concentration
• (S.Ocjs + 3.35cjs)
This theoretical calculated average of 922 mg/L is comparable to the value of 982 mg/L actually measured in
August 1994 at site 1005 downstream from the confluence of Fish Creek and Trout Creek.
EASTERN MINING DISTRICT
Prior work has been conducted on the alluvial valley Floor determination, and the Division has made a positive
finding of the existence of alluvial valley Floor downstream on Foidel and Middle Creeks. Twentymile is in the
process of generating data to modify the designation of the mid-reaches of Foidel and Middle Creeks as alluvial
valley floors due to the land use criteria.
Map ] 5, Alluvial Valley Floors and Water Rights, presents the alluvial valley floor designations. As shown on the
map, the confluence area of Middle and Foidel Creeks is the major alluvial valley floor in the area. This area,
along with the other mid-reaches of Foidel and Middle Creeks, will be undermined and subsided; but, based upon
the work done by Twentymile (refer to Fish Creek alluvial valley floor study. Technical Revision No. 14),
agricultural activities will not be interrupted, precluded, or discontinued on the valley Floor. The present
monitoring work Itas not shown any changes to the stream and its valley floor. During late August or early
September 1993, longwall mining of panel number 9 Right will commence: this will provide further data as [o the
impact to [lie stream and valley floor. As projected, approximately I.5 feet of subsidence will occur in the stream
channel. However, as indicated in the projections, no impacts are anticipated to the stream and the valley Floor.
(1 Sc•Js x 320mg / L) + (2.Ocfs x 1,7~6mg l L)
= 489mg / L TDS Concentration
(15cfs + 2.Ocfs)
MR 97- I ~4 2.06-23 12/09/97