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Lyons Quarry ��` <br /> 112d Reclamation Permit Operations Z <br /> Technical Revision <br /> 1 Introduction <br /> 1 .1 Purpose and Objectives <br /> The purpose of this document is to support the request to the Colorado Division of Reclamation <br /> Mining and Safety (DRMS)for a Technical Revision JR)to the 112c Reclamation Permit Operations <br /> for Lyons Quarry (File number M-1977-141). The objectives of this document are to provide a <br /> narrative and updated Exhibits that explain the requested revisions to the approved Reclamation <br /> Plan based on changes in the mining operations at Lyons Quarry. Revised Exhibits include the <br /> following: <br /> Exhibit E— Reclamation Plan <br /> Exhibit F—Reclamation Plan Map <br /> Exhibit L— Reclamation Costs <br /> Rule 6.5—Geotechnical Stability Exhibit <br /> The purpose for executing this effort is to allow for revised slope configurations of the quarry <br /> highwall areas to be in compliance with the standards set forth in the DRMS Mineral Rules and <br /> Regulations for the Extraction of Construction Materials (July 15, 2019); Section 3.1.2 which states <br /> in part: <br /> (3.1.2.1) Grading shall be carried on so as to create a final topography appropriate to the <br /> final land use selected in the Reclamation Plan. <br /> (3.1.2.3)All grading shall be done in a manner to control erosion and siltation of the affected <br /> lands, to protect areas outside the affected land from slides and other damage. If not <br /> eliminated, all highwalls shall be stabilized. <br /> (3.1.2.7) Maximum slopes and slope combinations shall be compatible with the configuration <br /> of surrounding conditions and selected land use (OMLR, 2019). <br /> Specifically, Aggregate Industries requests to grade and stabilize the highwall areas to meet the <br /> slope stability and surrounding topography requirements by excavating, processing and either <br /> backfilling or exporting the overburden sandstone material from the site. The dacite highwalls will be <br /> stabilized by scaling and using rock bolts to allow for appropriately distanced and protected, public <br /> viewing of this unique geologic formation as well as provide suitable habitat for avian and bat nesting <br /> areas. This revised plan will not go beyond the already disturbed mining boundary and will <br /> dramatically reduce the amount of blasting and extensive material handling required by the current <br /> approved plan (M-1977-141 Technical Revision #2); which specifies stabilizing the highwall by <br /> backfilling against the near-vertical slopes. <br /> A summary of the approved design in M-1977-141 Technical Revision#2 involves a backfill buttress <br /> against the dacite formation to blend with the cut slopes in the overburden sandstone. The <br /> sandstone would be excavated using drill and blast methods to achieve overall 1.5H:1V <br /> (horizontal-.vertical) slopes. Fill slopes in the pit highwall area would be placed and compacted to <br /> March 2021 1 1 <br />