Laserfiche WebLink
1.0 INTRODUCTION <br />This report summarizes geotechnical observations conducted February 20 and 26, 2007 on the <br />active and inactive mine areas at the Morison Quarry operated by Aggregate Industries (AI). <br />This report is intended to supplement the "2006 Notice of Intent to Continue Mining <br />Operations /Annual Report" for the Momson Quarry. Joint and foliation attitudes were <br />mapped for azeas mined in 2006 in order to characterize the rock mass exposed. Other features <br />affecting stability such as shear zones, faults, or failure surfaces, were described and mapped <br />as well. The field data collected was used to make recommendations regarding the <br />configuration of future mine slopes. This addendum, therefore, provides information required <br />by Permit Amendment #5 {carved over from Permit Amendment #3 and #4) to Mining Permit <br />M-1973-021. <br />1.1 Observational Method <br />Previous Permit Amendments describe the "Observational Method", which is a process of <br />observing highwall development to evaluate the rock mass stability and recommend slope <br />angles. The default slope configuration at the quarry is conservatively defined at IH:1 V <br />highwall height to bench width. Ongoing observation of the rock mass is used to alter the <br />default slope configuration when necessary for safety or desirable for production. Annual <br />Geotechnical Addendums as well as Technical Revisions to the Permit convey the information <br />gathered using the Observational Method to the Colorado Division of Mines and Geology for <br />review. <br />1.2 Site Deserintion <br />The Morrison Quarry is located west of Colorado Highway 8 approximately one mile north of U.S. <br />Highway 285 in Jefferson County, Colorado as shown on Figure 1. The site is situated in the Front <br />Range foothills west of the Dakota hogback. Mount Falcon Open Space Park is located west of the <br />site. The Quarry currently consists of a central mined area, the Central Quarry, in which active <br />mining no longer occurs, and a north mined area, the North Quarry, where active mining occurred <br />in 2006. The Central Quarry has been mined to an approximate elevation of 6330 feet above Mean <br />Sea Level {MSL) utilizing highwalls and benches and also contains a stabilized slope located in the <br />southeast section of the quarry. The North Quarry has been mined to an approximate elevation of <br />6260 feet above MSL utilizing highwalls and benches. Other activity in the North Quarry included <br />slope reclamation consisting of placing stripped overburden and weathered rock material on slopes <br />above approximately elevation 6500 feet above MSL. <br />2.0 2006 MINING SUMMARY <br />2.1 Centro! Ouarrv <br />Mining in the Central Quarry was completed as of December, 2001. The Central Quarry is <br />currently being used as a raw water reservoir for the use of the Town of Momson and Aggregate <br />Industries with an approximate water level elevation of 6430 feet above MSL at the time of this <br />report. As such, no major rock disturbance or mining occurred in the Central Quarry in 2006. <br />F:U919_038~Annual_Repart_2006Wnnual_Report 2006.doc - 1 - Apnl 207 <br />