2016-04-15_HYDROLOGY - C1996083 (6)

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` 970-249-6828 ■ 800-865-9847 (fax) ■ 222 South Park ■ Montrose, CO 81401 ■ www.dowl.com Alaska ■ Arizona ■ Colorado ■ Montana ■ North Dakota ■ Oregon ■ Washington ■ Wyoming COWL April 4, 2016 Huddleston -Berry Engineering and Testing, LLC 640 White Avenue Grand Junction, CO 81501 Attention: Mike Berry, PE SUBJECT: Summary Report, First Quarter 2016, Vibrating Wire Piezometers through March 2016, Bowie Mine No. 2, Coal Waste Disposal Area No. 3 Dear Mr. Berry, DOWL conducted quarterly monitoring of installed vibrating wire piezometers at Coal Waste Disposal Area No. 3 (CWDA No. 3), Bowie Resources, LLC. This report is intended to cover the time period of January through March 2016. VWP data was obtained on 3-21-16. A graphic plot of measured pore pressures over time is presented on the attached Figure 1, and numerically in Table 1 below. Table 1 summarizes the initial, prior and current readings and the difference in individual pore pressures since installation and prior readings. Table 1. Summary of Pore Pressure Readings VWP ID # Initial Pore Pressure 10/31/14 (psi)(psi) 12/19/15 Pore Pressure (psi) 3/21/16 Pore Pressure (psi) Difference Since Installation Difference Since Last Reading (psi) VWP-A Deep 10.4 7.0 4.4 -6.0 -2.6 VWP-A Shallow 4.7 4.6 4.5 -0.2 -0.1 VWP-13 Deep 1 0.2 1 0.1 1 -0.1 1 -0.3 -0.2 VWP-13 Shallow 13.9 14.7 13.7 -0.2 -1.0 VWP-D 7.1 7.0 6.3 -0.8 -0.7 If you have any questions regarding this letter or the instrumentation monitoring at CWDA No. 3, please don't hesitate to contact me at (970) 497-8827 or o62g dorf@dow/.com. Respectfully Submitted, DOWL Wayne Pandorf, P.E. Sr. Geotechnical Engineer Enclosure: Figure 1 — Vibrating Wire Piezometer Data Graph Bowie CDWA 3 Q1 2016 VWP Report 4-4-16 Project #7131.74526.01 Page 1 of 1