GENERAL33376

• Permit No: C1982057
• IBM Index Class Name: General Documents
• Doc Date: 9/4/1991
• Doc Name: PROPOSED DECISION & FINDINGS OF COMPLIANCE FOR PR1
• Permit Index Doc Type: FINDINGS
• Media Type: D
• Archive: No

The 'Wadge coal is in a confined condition in most cf the wells which have keen
monitored. At well GW-42-S 2'W-SW, a dcwndip well due •.aest of the south pit
area, the Waage appears to be semi-_-J.^.'ined. While pumping this well,
drawdown was obszrv?d in an adjdc?^~ a/?`oureen comp ?tion Nell. This
CCSer'/dtlOn 1nd1Cdt2S that tae'? '>, at tail iCC3ti0n, 3 hydrologic C::nneCLiv'n
between the 'Wadge arc the ovzrbu~aen.
P.quifer tests xer2 oerformed at `:+C .ve'15. One xell failed during ±he test.
The trdnsmissivity calculated a[ tie osier weal was 'j.03 FT2 per day, wnile
stcrativity has been estimated to o? on the Greer of 1 X i0-4.
Four n?lls 41ere Sdtfipled iCr xd'?" CU3!'ty CndraC`?riSLiCS. T!/C1C3'1y, thB
QUdiity Of this wdt?r vdri?S from C~ac? tJ 0'3C?. G?^er311y, Sulfate.
mahganese and total d15S0iVed S~~1lei ?<C??d bCLh J.S. [P.4 ahd Na*icnal AC3demY
e` Scienczs recommended drinking wat?^ crit?rid. Thesz Grit?ria, 'xhich are
generally accepted by the wat?r intluStry, may be found in 'Jolume 3, Tab 7,
Table 7-13, Page 7-34 of the pewit appiicdtion. Thesz watzrs arz unsuitable
for use as a drinking supply, but may be uszd for livestock watering. These
water; also post a high salinity haza-d to intolzrant plants, and therefore
may be unsuitable for use as irriga~ion wdt?r.
Wadge Coal Overburden
Slx wells dr? US2d t0 meniL'?r 'dd'?` QUaIIL'/ 3hd decth tC 'wdt?r In the
Williams Fork Formation 0`%?rCUrd2^ aCCv? `ill Wddg? COdI seam. The WlilldmS
Fork is a 50 to 500 fzet thick s?quznc? of sandstone, siltstone, shale, and
thin coal, including the Lznro.< Coa! S?3m.
Ground water in the Williams Fork *?nC: tJ flax daxndlp. Tn? rov?mint of
water and the horizontal extent of tie forma~icn is limited by outcrops in the
edstzrn and antral carts of ch2 oarmi_ area.
Generally, the Williams Fork '.s round :c o? in an unconrined state, however,
lccaily or seasonally the formation may ?rhibit semi-confine conditions.
S?dsonal fluctuations are probably the rzsult of recharging and de'xat?ring a
perched aquif?r within the formation.
Although aquifer tests were not performEd on the overburden at the site,
aquifer characteristics have be?n 2xtraccldtzd from Colorado Yampa Coal.
locat~ad about 15 miles scuta?ast. Da-3 ~bta?nod from thesz t?sts indicat?
that trdh5m1S51'/lty `/d1UeS fJr `~? 7v?~7Ur~72.^. C^U~C Y3hge ~n;m 3 t0 2~ y3~I0nS
pef dii% der fCOL (Q_4 rp 2.7 r~~ tl?` 7i!/~. xFl~? S~.~ra'IVity may V3^! from
1 x 10-~ t0 I !( 10-' 3i 1CC3i C:hd'L`.CnS Cn3^.C?.
One 'xE?11 'Nd5 SdmC:?^~ for 'da`.2'' ]U3!`."/. =''3~ iS2i Cf :hls mdgn?SiUT - C3iC~um
bicarbonate '•+Id t?f ShCw"c ?12'/dtEd 12'/?i, 7' 1rJh, manganese, TES, and Z'nC.
The high zinc values ar? probably dv? :, contamination from the galvanized
well sore?n. The high iron, TDS i:nd .T.d ^•yan2 i? '/31110_S pr?C1Ud? this `xd=?r dS 3
drinking supply. Williams Fork 'xa:?- `; suicadi? *or stock watering antl
irrigdtl0n or salt tolerant p'3nLi.
- 16 -