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970-249-6828 ■ 800-865-9847 (fax) ■ 222 South Park ■ Montrose, Colorado 81401 ■ www.dowl.com <br />Alaska ■ Arizona ■ Colorado ■ Montana ■ North Dakota ■ Oregon ■ Washington ■ Wyoming <br />Bowie CWDA #2 Q4 2017 VWP & Inclinometer report.docx <br />Project #7131.74699.01 <br />Page 1 of 2 <br />December 29, 2017 <br />Mike Berry <br />Huddleston-Berry Engineering and Testing, LLC <br />640 White Avenue <br />Grand Junction, CO 81501 <br />SUBJECT: Summary Report, 4th Quarter 2017, Inclinometer and Active Vibrating <br />Wire Piezometer Data October – December 2017, Bowie Mine #2, Coal <br />Waste Disposal Area (CWDA) #2 <br />Dear Mr. Berry: <br />DOWL conducted quarterly monitoring of inclinometers and vibrating wire piezometers (VWP) at <br />Coal Waste Disposal Area #2 (CWDA #2), Bowie Resources, LLC. This report is intended to <br />cover the time period of October through December 2017. VWP and inclinometer data was <br />recorded on 12/20/17. Per CDRMS and your instructions, vibrating wire piezometer readings for <br />all active piezometers are taken quarterly along with inclinometers. <br />Vibrating Wire Piezometers <br />The physical locations of the piezometers are shown on the attached Instrumentation Site Plan <br />(Map 1). As seen from this map, five of the original VWP’s were damaged and some were <br />replaced. Currently, there are five active VWP’s and three of them are associated with the three <br />inclinometers on this CWDA. The graph of historical data from 5/16/05 through 5/21/14 is <br />presented for reference as Figure 1. A graph of measured pore pressures of only active <br />piezometers is presented on the attached Figure 2 and is presented numerically in Table 1 <br />below. <br />Table 1. Summary of VWP Pore Pressure Readings <br />VWP ID # <br />Initial <br />Pore <br />Pressure <br />(psi) <br />9/20/17 <br />(Q3) Pore <br />Pressure <br />(psi) <br />12/20/17 <br />(Q4) Pore <br />Pressure <br />(psi) <br />Difference <br />Since <br />Installation <br />(psi) <br />Difference <br />Since Last <br />Quarter <br />(psi) <br />VWP-05 6.8 2.2 2.1 -4.7 -0.1 <br />VWP-06 11.3 13.2 13.0 +1.7 -0.2 <br />VWP-08 8.2 9.6 9.4 +1.2 -0.2 <br />VWP-09 2.8 2.8 2.8 0.0 0.0 <br />VWP-10 -1.9 -1.8 -1.8 +0.1 0.0