_REVISION - M1973021 (3) - Laserfiche WebLink

Home Browse Search

Aggregate Industries, Morrison Quarry Amendment No. 7 to Permit M-1973-021 Morrison, CO October 2021 | 18 Instead, mining will continue at the 40-foot highwall configuration with a minimum 40-foot bench configuration. Phase III Quarry Development Narrative Mining and reclamation will proceed from the present configuration (Exhibit C.2), using the same mining methods described in AM05. One modification to mining methods is the use of a portable crushing plant, referred to as the Road Base Processing Plant, located on the northern end of the South Quarry, to process rock for use in road development and reclamation activities. This plant will be removed and used at other sites when it is no longer needed (refer to Exhibit C.2 for its current location). The sequence of mining activities remains unchanged from AM05, which described mining as generally occurring on two "fronts" simultaneously: one continues South Quarry development, and one develops the West Quarry. Exhibit D.2 presents the Phase III buildout configuration plan view and Exhibit D.2a through Exhibit D.2c present the Phase III buildout configuration cross sections. The mining plan assumes a bottom elevation of El. 6,505; these numbers reflect planned benching in this area and average groundwater well water levels surrounding the South Quarry. The configuration reflects currently mined bench configurations and the maximum bench configurations identified in the previous section for areas where future mining will occur. Of note, the bench configurations identify some exceptions to the maximum configurations to tie future mining benches into completed benches in the South Quarry. Any changes in the identified bench configurations identified in this Mining Plan will be documented via the technical revision process for purposes of documenting other than minor effects upon the approved Reclamation Plan. West Quarry Haul Road Construction of the West Quarry Haul Road, a structure necessary to re-establish access to the upper benches of the South Quarry and commence West Quarry development, is underway and is scheduled for completion in late fall 2021. The Haul Road plans were summarized in Technical Review (TR07) and approved in July 2020. TR07 included the haul road design specifications and proposed configuration, but recognized that the final road alignment was pending and would be finalized in conjunction with AM07. Since the start of construction, fill material limitations have resulted in a change to the road alignment to maximize the use of cut material. Appendix 2 presents the final West Quarry Haul Road design, and Exhibit D.1 presents the final West Quarry Haul Road configuration. As mining and reclamation continues in the South and West Quarries, the haul road will be removed and reclaimed as benches progress eastward. South Quarry Development The South Quarry will be developed to a maximum depth before groundwater is encountered. Groundwater monitoring wells located north, south, and east of the South Quarry (MW2019-03, MW2019-02, and MW2019-01) show average water level elevations of 6,495, 6,581 and 6,459 feet, respectively. Based on these water levels, it is assumed that South Quarry base elevations