Laserfiche WebLink
<br />' S ' Alternative Reclamation Plan <br />i~i <br />SI-LB AGRA Project E92-7075 <br />Page 5 <br />1 <br />Production rock will be hauled to the plant by truck on a private, dedicated haul road. Trucks <br />' will be 85-ton dumps. The haul road location is shown on Map E and will cross four irrigation <br />ditches and State Highway 66 and the Burlington Northern Railroad track at grade. The road will <br />go over the St. Vrain River, cross land owned by Frontier Materials, Inc., then cross Boulder <br />County Road 49 and enter the cement plant property. <br />Improvements to public roadways will be performed as necessary and as required by the Boulder <br />County Public Works Department and the Colorado Department of Transportation. <br />The Hi-Cal bed is made up of limestone beds 1 to 2 feet in thickness separated by thin shale or <br />' clay partings. This bed has the highest lime content of any of the horizons at Dowe Flats and <br />therefore will be the most important of the horizons mined. In order to obtain sufficient material <br />from this bed to supply plant needs for the 25-year project life, a maximum 1,100-foot width pit <br />' is proposed. Maximum pit depth is estimated to be approximately 125 feet as measured from the <br />original ground surface. <br />' The 2nd Ridge consists of many thin limestone seams interbedded with shale. Reserves have been <br />calculated to a pit depth of 70 feet. <br />1 The 3rd Ridge has a thickness of about 30 feet. Recent studies have shown that the formation <br />' may be divided into three bands: a top higher-alkali portion nearly 8 feet thick; a center lower- <br />alkali band 15 to 16 feet in thickness; and a bottom zone of lower lime content which may be <br />upwards of 10 feet thick. These bands have traditionally been designated by chemical analysis. <br />They are very difficult to distinguish in the quarries by visual observation. Maximum pit depths <br />will likely be 60 feet. <br />' The 4th Ridge formation contains relatively high quantities of pyrite where it is fresh and <br />' unaltered. Near-surface weathering has removed the pyrite and has upgraded at least this portion <br />of the 4th Ridge to a useful material. Mining depths in this horizon will be somewhat shallower <br />than in the other limestone units, with a maximum of approximately 30 feet. <br />' A summary of mine data is shown on the attached spreadsheet. <br />AG RA <br />' Eerth & Environments/Group <br />