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<br />Aggregate Industries Morrison Quarry GEI Consultants, Inc. <br />Geotechnical Addendum, 2016 Annual Report 1 January 2017 <br />1. Introduction <br />This report summarizes geotechnical observations gathered on January 12 and 13, 2017 at the <br />Morrison Quarry, operated by Aggregate Industries (AI). This report supplements the <br />“2016 Notice of Intent to Continue Mining Operations / Annual Report” for the Morrison <br />Quarry. Rock characteristics such as joint and foliation orientation, shear zones, faults, and <br />instability zones were mapped for areas mined in 2016. Recommendations provided for mine <br />highwall configurations provided are based on GEI Consultants, Inc. (GEI) observations and <br />data analysis. This addendum provides information required by Permit Amendment #5 <br />(carried over from Permit Amendment #3 and #4) to Mining Permit M-1973-021. <br />1.1 Observational Method <br />The observational method for the Morrison Quarry is described in detail in Mine Plan <br />Amendments #3 and #4. This step-wise approach to slope design uses new observational data <br />to regularly update quarry highwall configuration. This methodology is used as a practical <br />approach to mine highwall design for rock mass with variable condition that is difficult to <br />classify. Newly obtained data is compared to baseline data obtained during previous <br />geotechnical addendums for analysis. This method has been used for slopes in the North, <br />Central, and South Quarries of the Morrison Quarry. <br />The annual geotechnical addendums allow for Colorado Division of Reclamation, Mining, <br />and Safety review of existing and evolving quarry conditions. <br />1.2 Site Description <br />The Morrison Quarry is located west of Colorado Highway 8 and approximately a ½ mile <br />north of U.S. Highway 285 in Morrison, Colorado. The site location is shown in Fig. 1. The <br />mine site is located west of the Dakota hogback along the Front Range west of Denver, <br />Colorado. <br />The Morrison Quarry consists of three cells; the North Quarry, the Central Quarry, and the <br />South Quarry. Active mining no longer occurs within the North or Central Quarries. The <br />North Quarry currently holds water utilized as mine process water. Within the North Quarry <br />footprint, the North Repository acts as a repository area for undesirable material such as waste <br />aggregate from mine operations or damaged or inoperable mine equipment. The North Quarry <br />was mined to an approximate bottom elevation of 6220 feet above mean sea level (MSL) <br />utilizing highwalls and benches at a nominal 1:1 ([horizontal:vertical] H:V) slope. Equipment <br />was placed in/removed from the North Repository during 2016 but no waste aggregate was <br />placed.