2017-08-08_REVISION - M1973021 - Laserfiche WebLink

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2. South Quarry Investigations 2.1 Pre-2017 Geotechnical Investigations Several subsurface investigations have been performed in development and support of highwall configuration design of the South Quarry, ranging in depth from about 30 feet to about 700 feet in depth. Subsurface investigation campaigns were performed in 2005 by Lyman Henn, in 2007 by Al, in 2007 and 2008 by GEI, and in 2011 by Tetra Tech. In 2005, Lyman Henn advanced seven HQ diameter boreholes and one NX diameter borehole (LH-01 —LH-07). The borings were advanced to depths ranging from about 27 feet to about 195 feet. Retrieved rock cores were measured for percent recovery and the percent rock quality designation(RQD), retained in core boxes and photographed. The rock types encountered included granitic and biotitic gneiss, with some pegmatitic intrusions encountered. Samples from the borings were submitted for laboratory testing, consisting of L.A. Abrasion testing. The boreholes advanced by Lyman Henn are summarized in Table 1. In 2007, Al advanced three vertical NQ diameter boreholes (2007 PHI-1 —2007 PH1-3). The borings were advanced to depths ranging from about 300 feet to about 500 feet. Retrieved rock cores were measured for percent recovery and retained. Tetra Tech estimated percent RQD based on photographs of the rock cores. The rock types encountered were logged as low grade migmatite, psammite, and meta pelite. The rock types and descriptions are essentially the same as granitic and biotitic gneiss encountered in other subsurface investigation campaigns. Samples from the borings were submitted for laboratory testing, including Micro Deval and L.A. Abrasion testing. The boreholes advanced by Al in 2007 are summarized in Table 1. In 2007 and 2008, GEI advanced three vertical HQ diameter boreholes and four HQ diameter boreholes inclined at 70' from horizontal (2007 PH 2-1 —2007 PH 2-3 and 2008 PH 3-1 — 2008 PH 3-4). The borings were advanced to depths ranging from about 300 feet to about 685 feet. The core was measured for percent recovery, retained in core boxes, and photographed. Tetra Tech estimated percent RQD based on photographs of the rock cores. The rock types encountered included granitic and biotitic gneiss,with some pegmatitic intrusions encountered. Samples from the borings were submitted for laboratory testing, including Micro Deval and L.A. Abrastion testing. The boreholes advanced by GEI are summarized in Table 1. In 2011, Tetra Tech advanced one vertical HQ diameter borehole to a depth of 690 feet (TT-01). The core was measured for percent recovery, percent RQD, retained in core boxes and photographed. The rock types encountered included granitic and biotitic gneiss, with some mafic dike intrusions, pegmatitic intrusions, and sillimanitic gneiss. Samples from the Aggregate Industries Morrison Quarry GEI Consultants, Inc. South Quarry Highwall Design Technical Revision 5 August 2017