2017-04-14_REPORT - M1974004 - Laserfiche WebLink

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Martin Marietta Materials Spec-Agg 2017 Annual Report material to the south of the fault is more difficult to blast. Large rock block fragments in the vicinity of the fault are often observed. A mapped reverse fault trending roughly north-south is located within the quarry property and constitutes the boundary between the metamorphosed Precambrian bedrock to the west and the Pennsylvanian sedimentary rocks to the east(Smith, 1964; Scott, 1972). The quarry property straddles this boundary, with the majority of the processing plant and the entire asphalt plant located east of the fault(Figure 3). The bedrock material east of the fault is dominantly composed of upturned sandstones and shales of the Fountain Formation (Scott, 1972). West of this fault, the material is mapped as migmatitic quartzo- felspathic gneiss with intrusions of granitic pegmatite veins (Scott, 1972). Two other approximately north-south trending faults have been exposed in the northern quarry walls, as shown on Figure 3 and discussed in the previous 2013 report (Lachel, 2013). They roughly parallel the Golden Fault, which is a major fault that forms the north-northwest trending hogback immediately east of the quarry property. These two faults remain unchanged since there is no mining activities in the main pit area. 4.0 MINING PLAN AND PROGRESS Mining activities have typically been focused in two distinct areas: the Main Pit and the Southern Expansion Area (Figure 2). It is our understanding that minimal or no mining activity except possibly some groundwater pumping has occurred in the Main Pit Area since the last report. Significant mining activity has taken place in the Southern Expansion Area since our last annual report and between our July and December 2016 site visits (Photos 1 to 3). The current temporary benches are being advanced to approximately EL 6,630 ft(Figure 2, Station 17-06)with reclamation occurring in stages following excavation along permanent benches. Three temporary benches were actively being mined during our site visits, including an upper bench near the western margin of the Southern Expansion Area (see stations 17-01 and 17-04 in Figure 2). The next lower bench is being mined starting from the eastern side approximately 35 feet lower than the upper bench and working to the west(see Stations 17- 02 and 17-05 in Figure 2). An additional area of recent mining was observed in the southeastern portion of the Southern Expansion Area (see Stations 17-06 in Figure 2). This area may represent the start of a new lower bench of the Southern Expansion Area. Based on the current mine plan developed by Martin Marietta (formerly Lafarge West, Inc.) in December, 2003, and the current Colorado Division of Minerals and Geology mine plan, we understand that the mine will eventually be excavated to the topographic configuration shown in Figure 2, with an approximate final mine floor elevation of EL 6,200 ft. The orientations of the final planned highwalls are the basis for our rock structural discontinuity assessment, as discussed in Section 6.0. February 27, 2017 Page 3 Lachel &Associates, Inc. Project 16C64003 00 ©2017 All Rights Reserved