GENERAL37368

• Permit No: C1984062
• IBM Index Class Name: General Documents
• Doc Date: 8/4/1992
• Doc Name: Midterm Review Findings Document
• Permit Index Doc Type: Findings
• Media Type: D
• Archive: No

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plL'Ge 'd1L 'n th? G`i?rtiUrG?n dgUlf?r and p0Lentldl '/ertlCal Lr'dn5ml;;lOn through
faults tc ether aquifers i; a potential impact that may have undesirable
long-term com ?quences.
After revi2`N of *.he pertinent sections of the permit application related to
water issues, it is evident that some of the predictions and pos;ibi?
conseeuenr?s dealing with the hydrology ar? in error Gr are rontrddictory.
Identification of questionable areas is as follows:
Text - Page 2.05-69 says soil stabilization techniques such as chisel plowing
and contour furrows will create ccnditions of no runoff 'rpm a 10-year, 24-hour
event (infiltration estimate = (85%:> (1.41")>, i.e., no surface runoff is
expected from reclaimed lands.
OMLR Comment - From review of actual conditions at Mine IVO. 3, this prediction
is clearly inaccurate and needs change or modification based on actual data.
Tex* - Page 3.05-165 - No dewatering 'was bJ tak? plac? oe7au;e the pit w,.; nGt
inters?pt a saturated portion of the overburden aquifer.
OMLR Comment - Inspection of Map 1, T`.ventymile Park Hydrology, and Hap 2,
Geology, indicat?; that the pit would dnd did in fdct penetrate the cverburden
peizometric surface by 25 feet or more. Thi; section also needs modification
based on actual data.
Text - Page 2.05-154 stet?s that "mechani7al breakdown, eLC.,...'.vill increa<_e
permeability" but page 2.05-156, Lusby & Tcy (1975), read; "infiltraticn rat?i
of reclaimed Iand are lower than the ;ame land in pre-mining condition."
Page 2.05-167a rands "permeability in backfiii 'Mill exceed that of the
undisturbed aquif?r."
OMLR Comment - Thes? comment; contradict ?ash other. The appropriate text
shoula be romp`/ed basal on actual condition<_.
Text - Page 2.05-168a reads "...recharge to the backfiiled spoils aquif?r (140
acre-f??*. Ger ye=_r) ;nculd be ab;Jrbed by th? adjacent overburden aauifer."
GMLR GJmme^,L - rcm r?vie`N of the 1991 '.YaL?r level data f7r ;coil<. well
C)GB-SP-.7d, thl;r~l3; nCt tdk?^, p1dC?. IL 1S noted, h0'NeVEr, that th? ;pCli 'Heil
OGS-SP-1d 'n Ln? ;JULnErn m;,".2 d`?d hd; al'dd'/S been dry. Howe`/2r, re`/12'N Of
elevation information er-cvioed indicates that 008-SP-4a .+as Gositioned some 40
feet above the i0w?;t Olt elE`/d C1Jn 3fld Lh e!'efOr? dOeS HOC present r?i7dOle
information on ;peal aquifer de/elopment. This section concerning spoil aquifer
development ne?d; r?`/lied t0 dCCUrdt?ly r?pr?Sent dCtUdl conditions.
Te:<t - Page 2.07-i7id r?dd; "ThE leaching study a1sJ re;olt?d in a predicted
level Of S311n'. t in lea_hd `.? 'da .?r;...Lh? p"?~!1 Cted COnC?nLrdtlOn Of d15iOlVB~