Appendix F3 Mine Deformation Study

AGUA MANSA COMMERCE PARK SPECIFIC PLAN DRAFT EIR CITY OF JURUPA VALLEY Appendices Appendix F3 Mine Deformation Study December 2019 AGUA MANSA COMMERCE PARK SPECIFIC PLAN DRAFT EIR CITY OF JURUPA VALLEY Appendices This page intentionally left blank. PlaceWorks MINE DEFORMATION STUDY FINITE ELEMENT ANALYSIS REPORT for AGUA MANSA COMMERCE PARK 1500 Rubidoux Boulevard Jurupa Valley, California Prepared For: Crestmore Redevelopment LLC 1745 Shea Center Drive, Suite 190 Highlands Ranch, CO 80129 Prepared By: Langan Engineering & Environmental Services 32 Executive Park, Suite 130 Irvine, California 92614 18 August 2017 700045406 18 August 2017 Mine Deformation Study Page i of i Finite Element Analysis Report Agua Mansa Commerce Park Langan Project No.: 700045406 TABLE OF CONTENTS 1. INTRODUCTION 1 2. PROPOSED DEVELOPMENT 1 3. BACKGROUND INFORMATION 1 3.1. Crestmore Mine 2 3.2. Site Geologic Setting 2 4. FINITE ELEMENT MODEL 3 4.1. Subsurface Conditions Model 3 4.2. Model Development 4 4.3. Material Properties 5 4.4. Mine Geometry 7 4.5. Mesh Generation 7 4.6. Loading Conditions 7 4.7. Staged Construction Modeling 8 5. RESULTS OF FINITE ELEMENT MODEL 9 5.1. Mesh Generation Ground Surface and Mine Roof Movements 9 5.2. Induced Stresses on Mine Pillars 9 5.3. Model Verification/Calibration 10 6. CONCLUSIONS 11 7. LIMITATIONS 12 FIGURES Figure 1 – Finite Element Model Boundaries and Cross-Sections Figure 2 – Finite Element Model Boundaries and Geometry Figure 3 – Mine Levels Isometric and Plan View Figure 4 – Construction Modeling Stages 1, 3, 5, and 6 Figure 5 – Mine Roof and Ground Surface Vertical Movements – Stage 3 Figure 6 – Ground Surface Vertical Displacements Figure 7 – Mine Roof Vertical Movements – Stages 5 and 6 Figure 8 – Effective Stress Diagrams – Unloading Conditions Figure 9 – Stage 6 Horizontal Room-Roof Stress at mine level 210 Figure 10 – Stage 6 Maximum Vertical Stress at Pillars APPENDIX A – Reference Documents 3 August 2017 Mine Deformation Study Page 1 of 12 Finite Element Analysis Report Agua Mansa Commerce Park Langan Project No.: 700045406 1. INTRODUCTION As requested by Crestmore Redevelopment, LLC (Crestmore) on 26 June 2017, Langan Engineering and Environmental Services, Inc. (Langan) has performed geotechnical and geological engineering services for the proposed project (Aqua Mansa Commerce Park) located at the former Riverside Cement Plant (“site”). This “Mine Deformation Study Finite Element Analysis Report” summarizes the previous document reviews and the results of the deformation study performed using finite element methods. The purpose of the study was to estimate potential changes in stress-strain conditions (i.e., pressure distributions and associated deformations) at the belowground mine chambers and corresponding ground surface deflections due to the proposed development of the Aqua Mansa Commerce Park. This report summarizes the mine background information including a brief description of the mining at the site and a summary of the proposed development, a description of the finite element analysis, the results of the analysis and a summary of conclusions. Additional details regarding the site geotechnical conditions are presented in the report titled “Preliminary Geotechnical Investigation Report”, prepared by Langan, dated 28 April 2017 and the “Mine Study Report” prepared by Langan, dated 25 April 2017. 2. PROPOSED DEVELOPMENT Based on a review of plans and exhibits provided by Crestmore, including a Draft Preliminary Site Plan dated 7 September 2016 and a April 2017 topographic map prepared by DRC Engineering, the proposed development consists of a commercial/ industrial complex that includes up to 4 single story industrial buildings (identified as Buildings 1 through 4) with potential mezzanine levels totaling a combined footprint of approximately 3.6 million square feet. Site development will require installation of new utilities, and mass grading that could include cuts of up to 35 feet and fills of up to 75 feet. 3. BACKGROUND INFORMATION The former Riverside Cement Plant is located near the intersection of Aqua Mansa Road and Rubidoux Boulevard in Riverside County, California. The northern part of the site is overlain by fill and is vegetated with shrubs, grass and trees. The remainder of the site contains fill stockpiles including material stockpiles, berms and filled former quarry areas. Ground surface elevations vary from approximately 835 feet above mean sea level (amsl)1 to approximately 985 feet amsl. 1 Elevations are based on the National Geodetic Vertical Datum of 1929 (NGVD 1929) as referenced from DRC Engineering, Inc. “Encumbrance Map, Vacant Commercial Property, Jurupa Valley, California” dated 2 March 2016 18 August 2017 Mine Deformation Study Page 2 of 12 Finite Element Analysis Report Agua Mansa Commerce Park Langan Project No.: 700045406 The Riverside Cement Plant operations included quarries and an underground mining operation (i.e., the Crestmore Mine) that was used to obtain limestone for use in manufacturing cement. The quarries were located south of the proposed buildings; additional information about the location of the quarries is presented in the previously cited reports. Underground mining was initially performed beneath the Chino Quarry, which is located about 700 feet south of the proposed development. Mining progressed north and east as successively lower mining levels were excavated. 3.1. Crestmore Mine Underground mining at the site began in about 1930. Block caving method was used from 1930 through 1954 in the mine area beneath the Chino Quarry. As the mine progressed deeper, room pillar mining was used from 1955 until about 1986, when the mining ceased and the “rooms” were allowed to fill with water. The limestone formation dips to the east and pitches to the northeast, and the room and pillar mining followed that trend; thus, each successively lower mining level was offset somewhat to the north and east. Available mapping dated between 1960 and 1970 indicates that ten mine working levels are documented for the Crestmore Mine. The shallowest of those mine workings beneath proposed Building 1 occurs at a mine floor elevation of 440 feet amsl. Shallower mine workings exist at mine floor elevations of 572 feet and 542 feet; however, the mine workings at the elevations of 572 and 542 feet are located outside the proposed Building 1 footprint. Deeper mine workings are mapped at mine floor elevations of 400, 330, 290, 220, 130, 35, and -60 amsl. 3.2. Site Geologic Setting The site is located on the Perris Block in the eastern end of the Jurupa Mountains on the south side of the San Bernardino Valley, which lies within the Peninsular Ranges geomorphic province of California. The Perris Block is the central block of three major fault-bounded northwest- southeast trending blocks of the northern part of the Peninsular Ranges. The Perris Block is bounded to the east by the San Jacinto Fault Zone, to the north by the Cucamonga Fault Zone, and to the west by Elsinore Fault Zone; and, it is considered to be internally un-faulted and therefore structurally stable. The Perris Block is underlain by lithologically diverse pre-batholithic meta-sedimentary rocks intruded by plutons of the Cretaceous age Peninsular Ranges batholith. Limestones (aka, the mined “ore bodies”) are present as two generally irregular, roughly parallel, lenticular sedimentary members dipping primarily east-northeast and pitching to the northeast The upper and lower limestone bodies are referred to as Sky Blue and Chino Limestones, respectively and 18 August 2017 Mine Deformation Study Page 3 of 12 Finite Element Analysis Report Agua Mansa Commerce Park Langan Project No.: 700045406 are mineralogically similar. However, the upper member was highly fractured and water bearing in contrast to the lower member. The limestone members are enveloped and cut by intrusive igneous rocks that resulted in alteration due to contact metamorphism of the limestone, which became coarsely crystalline and locally predazzite marble. The country rock within the boundary of the site consists predominantly of quartz-biotite diorite. Although quartz monzonite pegmatites occur commonly as small or thin dikes in the porphyry and country rock and extended generally less than 2 or 3 feet into the limestone. The contact rock predominantly consists of Hornfels. In addition, available Riverside Cement structure logs (taken from diamond drill holes during the original mine investigation) indicate at least 4 predominant joints sets are present in the roof rock mass. The majority of the joints are described as being rough or cemented. Erosional depositional surfaces are developed on the Perris Block and Quaternary age non- marine sediments of varying thickness discontinuously mantle the basement rock. In particular, the northern portion of the site (i.e., beneath the proposed buildings) is underlain by Holocene to late Pleistocene age alluvial fan deposits consisting of gray alternating layers of mixtures of sands, silts, and clays having varying proportions of gravel and cobbles with occasional boulders. Locally, near the surface are man-emplaced uncontrolled fills consisting of talus materials and intermixed cement materials from the cement manufacturing operations. 4. FINITE ELEMENT MODEL The finite element analysis was performed using the program Midas GTSNX 2017 v.2.1. Midas GTSNX is a finite element analysis software package that was developed specifically to perform fully coupled analyses for geotechnical applications.

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