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NORWEST Suite 1830, Hastings Street <br /> Vancouver, <br /> ver, BC V6E 3X2 <br /> Tel: (604)602-8992 <br /> COR PORAT ION www.norwestcorp.com <br /> ■o <br /> Ong /�I organirational Quality• <br /> 1,���/j Management Program <br /> Memorandum <br /> To Transit Mix Concrete Co. Project# 591-6 <br /> CC Peter Kimball,Tim Peterson, Paul Kos Date March 13, 2018 <br /> From Alvin Tong <br /> Subject Hitch Rack Ranch Quarry Waste Stockpile Stability Analyses <br /> 1. INTRODUCTION <br /> Norwest Corporation (Norwest) was retained by Transit Mix Concrete Co. (Transit Mix) to provide state- <br /> permit-level design and engineering support for the proposed Hitch Rack Ranch Quarry (HRRQ) granite <br /> quarry in Colorado, USA.The proposed quarry is located approximately 15 miles south of Colorado Springs, <br /> CO, in El Paso County. The site is currently serviced by Little Turkey Creek Road via Colorado State Highway <br /> 115 and is currently unimproved with relatively steep hills rising to the north and south. Little Turkey Creek <br /> flows generally west to east through the middle of the proposed quarry location. The quarry operation <br /> will be located south of Little Turkey Creek. <br /> As part of permit application,the state requires stability analyses to be completed on the topsoil and fines <br /> stockpiles for the project. Currently, there are six stockpiles planned for the project: Topsoil Stockpile 1 <br /> to 4 (TS1 to TS4) and Fines Stockpiles 1 to 3 (F1 to F3). TS2, TS3 and F1 are located west of the open pit, <br /> TS1,TS4, F2, and F3 are located in mined out pits. The general arrangement plan is shown on Figure 1 and <br /> shows the extents of mining when F1, F2,and F3 have reached their maximum extents.This memorandum <br /> presents the stockpile stability analyses completed, as well as the development of the geotechnical <br /> parameters, and the design recommendations to maintain sufficient slope stability for the stockpiles. <br /> 2. 2015 AND 2017 SITE INVESTIGATION <br /> Norwest completed drilling programs in 2015 and 2017 in the nearby areas. The 2015 holes were <br /> completed using a diamond coring method, intended to characterize the rock condition for pit wall <br /> evaluation. The 2017 holes were completed using the air rotary method, intended to characterize <br /> groundwater conditions in the project area. Some overburden was recovered from the drilling program, <br /> but the recovery was marginal. Visual inspection of the soil describes the overburden as "up to 4 feet of <br /> coarse grained brown top soil with rock clast". <br /> Regional information from public accessible database was used to supplement the geotechnical <br /> information from 2015 and 2017 investigations. Regional information is deemed sufficient for this permit <br /> level design as the project site is relatively small, limiting the variability of the geomorphology on site. In <br /> Calgary/Vancouver/Saskatoon/Salt Lake City/Denver/Charleston <br />