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Inclinometers <br />Three inclinometers, designated BG05-04, BG05-05, and BG05-07, were installed at CWDA #2 <br />in August 2005. The inclinometers were installed through the coal refuse and approximately 20 <br />feet into the native foundation soils. The physical locations of the inclinometers are shown on <br />the attached Instrumentation Site Plan (Map 1). Baseline readings were taken on 8/10/05 and <br />subsequent readings have generally been taken quarterly since that time. Displacement curves <br />for each of the three inclinometers for the current and prior three readings are presented as <br />attachments to this letter in Figure 3. Axis "A" reflects deformation with depth in the direction of <br />anticipated movement (downslope), while Axis "B" is orthogonal to Axis A. As described in <br />previous reports, we are of the opinion that historic displacements indicated on the plots for the <br />approximate upper ten feet of the inclinometers are likely due to placement of cover soil on the <br />face of the waste bank during normal operations for maintenance and revegetation. The March <br />2017 reading for BG05-05 appears anomalous either due to operator error or equipment <br />tolerances. <br />If you have any questions regarding this letter or the instrumentation monitoring at CWDA #2, <br />please contact me at (907) 562-2000 or iho//and(@dow/.com. <br />Respectfully Submitted, <br />DOWL <br />Enclosures: Map 1 - Instrumentation Location Plan <br />Figure 1 — Active and Damaged Piezometer Data Graph (2005-2014) <br />Figure 2 — Active Vibrating Wire Piezometer Data Graph (to present) <br />Figure 3 — Inclinometer Displacement Curves <br />Bowie CWDA #2 Q2 2017 VWP & Inclinometer report.dooc <br />Project #7131.74>ox.01 <br />Page 2 of 2 <br />;:; 40723 :0 <br />o •�Z, <br />ss�O1V .. E. <br />Jeremiah E. Holland, P.E. <br />Geotechnical Engineer <br />JEH/Ijb <br />Enclosures: Map 1 - Instrumentation Location Plan <br />Figure 1 — Active and Damaged Piezometer Data Graph (2005-2014) <br />Figure 2 — Active Vibrating Wire Piezometer Data Graph (to present) <br />Figure 3 — Inclinometer Displacement Curves <br />Bowie CWDA #2 Q2 2017 VWP & Inclinometer report.dooc <br />Project #7131.74>ox.01 <br />Page 2 of 2 <br />