2007-10-30_REVISION - M1977208

• Permit No: M1977208
• IBM Index Class Name: Revision
• Doc Date: 10/30/2007
• Doc Name: Response to adequacy review letter
• From: Cemex
• To: DRMS
• Type & Sequence: TR9
• Media Type: D
• Archive: No

Oct 30 2007 7:49RM Cemex Inc. 303 823 2199 p,4
Ms. Erica Crosby
October 29, 2007
Page 3
although the absence of selettiutn in the ground water is a positive sign that supports
limited hydraulic connectivity.
GEMEX Response: CFMEX agrees.
h. Concluaione
On page 4-1, reference is made that a hydraulic "connection is not evident at
compliance well CEM-005."
Response: An insufficient number of samples (has] been collected from CEM-005
to confidently draw that conclusion. However, DRMS acknowledges that the
presence of only 4 feet of water in the 400-ft deep CEM-005 well is a strong
indication of low hvdrauhc connection.
CEMEX Response: CEIKEX agrees. Ar indicated in e. about, we wild tantinue to monitor the depth
to mater at CEM-0O5.
2. The report notes the degradation of shotcxete lining within the Boulder Feeder Canal
and possibly water migrating to the C-Pit as noted by seeps in the highwall and well
vegetated areas. Based on the report, it appeals [hat water from irrigation ditches (s)
migrating into the C-Pit. Ia order to reduce the water flowing inro the C-Pit and corning in
contact with the cement kiln dust (CKDj, CEMEX will need to provide a plan to limit the
seepage flow oEwater into the C-Pit.
CEMEX Response: CEIt1EX proporer to addnrr the ditch seepage issue in a rtcp-wire fashion,
initurlly focusing an to/utianr to known problems and asrerring the results, prior to spending rzroun~er on
calving potenfial problems shat haveyet tv be proven.
Obrervationt made ibis part irrigation rcaron along the Boulder Feeder Cana! rautb of the bn'dge crornng to
B-Pit indicated that rerpage from the Canal in tbu rea<l~ which ar built on an engineerzd fill, make iu way
to the 54-inch arlverY under the Canal, dirchmging to the pond southwest of C-Pit. (See Figure 2 of the
TA-8 Ilepart, andphatas to Appendix c.J In adds'tion, the rauthwert pond bar siren reverxtl feet averibe
rvurre of the rummer, and it currently at its highut pvinz Conversativnr with the Northern Coivrado
Water Canrervancy District (_r~Tartbern) haue anfirmed that fdow in the Feeder Canal in reatnt weeks bas
been running at 20-SO CFS, and will rontinue to run at approximately 10 GFS until November 6, 2007,
at which time it wiU be shut down far ibis rtaran.
In contrast to the continudng flow in the Feeder Canal flow in the Swede Ditch (that it rontained in the
CMP culvert along the dap of the nrerttrn C-Pit higbwall) ceaed in mid September, 2007 Field
observations an October 23, 2007 cnnftrmed that reefw8e mntlnuer to enter C-Pit through fractures and
bedde'ng planer in the western highwald CE161EX has theroforz concluded that the primary if not sole
rourzr of this highwa!lseepage u from the Feeder Canal and not the Swede ditch.
CEMF.X proporer the following ar an initial phase of work to address seepage into C-Pit:
I2'ne 800 feet of the rvuthern reach of the Feeder Canal (that t} built on the fill embankment rauth
of the B-Pit bridge) with clay, :rr the arts known to be kake'ng into the 54-inch exlveK. Discussions
regarding thin plan have alrtady taken place with Nortlxrn, who will cooperate with CEMEX in
tin's effort. This k'ning project will be <ompkted prior ao the 2008 irrigation reason, at which time
the bigbwa/1 and C-Pis water levek wilr be monitored to arrest the effect of lining this reach of the
Canal
Deft Response to 10-5-07 Adequacy ]tcview_TR-9_REV2