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<br />one: (970) 878-3574 <br />t Fax: (970) 878-5866 <br />~~~ ` <br />Mr. Paul S. Osborne ``-_7 L C _ '~ ~ L7 v RECEIVE <br />Ground Water Program <br />U.S. EPA Region VIII, Mail Code BP-W-GW ACT Z 7 20a~ ~/ <br />999 18"' Street, Suite 300 <br />Division of Minerals and , <br />Denver, CO 80202-2466 <br />Subject: ~ e CFA 11 mpletion Status d Logging Results for Subsidence <br />Monitoring We113M-TDR <br />Dear Mr. Osborne, <br />As a result of recent 3M-TDR subsidence monitoring well (SMW) completion <br />activity and discussions with the BLM and EPA, this letter provides well <br />completion details and cement bond, CCL, caliper logs. Geologic interpretation of <br />the drilled hole indicates the top of the L-5 zone and the Bottom of the R-6 zone is <br />at 1784 feet from surface (FFS), the $-Groove is from 1572 to 1602 FFS and the <br />A-Groove from 1380 to 1396 FFS. A Lang Exploratory Drilling rig (reverse <br />circulation) performed the drilling and completion. In summary, drilling began <br />9/30/03 and total depth 1845 FFS achieved 10/4/03. An 8 3/4" hole was drilled. <br />Next, 4 1/2" casing with four TDR cables banded to the outside every 40 feet, were <br />run in the hole to 1840 feet. Ends of the TDR cables were installed 55, 75, 95 <br />and 115 feet above the Dissolution Surface (1896 feet). A two-stage cement job <br />was performed, the DV tool was at 1385 FFS). Premium cement (150 sacks) and <br />50/50 POZ (185 sacks) were utilized for cementing, with ~98% excess. Cement did <br />not come to surface. <br />Per NSI logging interpretation, good quality cement is present up to 1768 FFS, <br />providing coverage above the L-5 and ~16 feet into the R-6 zone and therefore <br />isolating the poor water quality associated with the Dissolution Surface and L-5 <br />zone. Possibly, poor quality cement is evident up to 490 FFS. The effect of the <br />four cables on the cement bond log (CBL) may influence the CBL results. Another <br />type of log will be run to hopefully provide better interpretation above the top of <br />good cement at 1768 FFS. Initially after cementing and follow-up readings after a <br />week, the TDR cables indicate all four cables are performing satisfactorily and <br />clearly indicate end-of--cable results. <br />