M E M O R A N D U M. Mr. Jonathan K. Thrasher, P.E., Mr. Ian Kinnear, P.E. (FL) PSI

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1 M E M O R A N D U M TO: FROM: Mr. Mark Schilling Gulf Interstate Engineering Mr. Jonathan K. Thrasher, P.E., Mr. Ian Kinnear, P.E. (FL) PSI DATE: November 11, 2014 RE: Summary of Findings Geotechnical Study Proposed Alexander City Compressor Station (CS-1) Sabal Trail Project Alexander City, Tallapoosa County, Alabama PSI Project No The purpose of this memo is to provide a summary of findings of the geotechnical study that we are currently carrying out in connection with the noted project. The Compressor Station site being evaluated is Option 1 located on the south side of Brick Plant Road approximately one-half mile east of the intersection of Brick Plant Road and Campground Road. A plan view of the site is included on Sheet 1. The geotechnical study included drilling and sampling twelve engineering borings and eight hand auger borings. The approximate locations at which the borings were completed are shown on Sheet 1. Following the completion of drilling, we staked the borings in the field and the surveyors have established coordinate and ground surface elevation information for each exploration. This survey is included on the attached Table 1. The engineering borings were sampled following Standard Penetration Test (SPT) procedures of ASTM D SPT samples were recovered continuously to a depth of 10 feet and at 5 foot intervals thereafter to boring termination. The engineering borings were extended to depths of up to 43.5 feet below existing grade. Drilling was carried out by a PSI drill crew with a Project Engineer in the field to log the materials recovered from the explorations. An ATV rig with a safety hammer was used to drive the SPT sample spoon. Samples recovered from the SPT borings were visually stratified in our Orlando laboratory following guidelines contained in the Unified Soil Classification System (USCS). Boring logs are attached. Select samples have been tested in our laboratory and the results of these tests are included on the boring logs adjacent to the depth interval at which they were recovered. The eight hand auger borings were advanced to depths in the range 8 to 10 feet below grade. Soil samples were recovered from the flights of the augers at regular intervals. The hand auger borings were completed to assess the shallow soil and groundwater table conditions in the planned pavement areas. Boring logs indicating the results of the hand auger borings are also attached. Professional Service Industries, Inc rd Street Orlando FL Phone 407/ Fax 407/ Engineering Certificate of Authorization 3684

2 Gulf Interstate Engineering November 11, 2014 PSI Project No Page 2 of 2 The results of the borings indicate an overburden consisting of predominantly sandy clays and clayey sands underlain by silts and silty sands. Generally, the clay/clayey soils extend up to about 13.5 feet below the existing ground surface while the silts and silty sands persist to or near the boring termination depths. The clay/clayey soils typically have medium-stiff to very-stiff consistencies, the silts typically have medium-stiff to very-stiff consistencies and the sands typically were typically in a medium-dense to dense condition. It should be noted that some of the soils recovered as silty sands from near the termination depths in the deeper explorations are most likely weathered bedrock that was affected by the drilling process. We recovered only a few small fragments of the bedrock material and were only able to penetrate the material a few inches. Based on a review of the published geologic information for the area and the rock fragments recovered, the bedrock probably consists of schist or gneiss though quartzite may also be present. The local geologic formations are typically very hard which was confirmed by the difficulty drilling through the bedrock, even when using a specialized drill bit. Drilling was continued for up to 23 minutes with less than one inch of advancement. Typically, the structure borings were terminated after encountering bedrock through which we could not readily progress. SPT blow counts in the schist/gneiss were typically 50 blows for four inches or less of sample spoon penetration. On Table 2 (attached) is a summary of the top rock versus depth for the deeper borings completed for this study. This site is located in an area that has a very low risk of sinkhole potential and consequently, no geophysical testing was carried out for this facility. Groundwater was not observed in the majority of the borings. In borings BH-6 and BH-16, water was encountered at depths of 6 and 8 feet, respectively, below the existing surface. The observed water levels in these two borings were likely due to temporary perching of water in isolated zones of sandy soils. We trust that the foregoing and accompanying attachments are of assistance to you at this time. Let us know if you have any questions and/or comments or if you require additional information. Best Regards, PROFESSIONAL SERVICE INDUSTRIES, INC. Certificate of Authorization No Jonathan K. Thrasher, P.E. Project Engineer Alabama License No Ian Kinnear, P.E. (FL) Chief Geotechnical Engineer (Compressor Station 1 Data Memo) Attachments Tables 1 and 2 Sheet 1 Location Plan Boring Logs

3 Gulf Interstate Engineering T-1 PSI Project No TABLE 1 GPS Coordinates and Elevations of Boring Locations Alexander City Compressor Station (CS-1) Alexander City, Alabama Boring No. Boring Type Latitude Longitude Elevation (feet) BH-1 Auger BH-2 SPT BH-3 Auger BH-4 Auger BH-5 SPT BH-6 Auger BH-7 SPT BH-8 SPT BH-9 SPT BH-10 SPT BH-11 Auger BH-12 SPT BH-13 Auger BH-14 Auger BH-15 Auger BH-16 SPT BH-17 SPT BH-18 SPT BH-19 SPT BH-20 SPT Note: GPS coordinates and ground surface elevations provided by Ken McDonald with GIE.

4 Gulf Interstate Engineering T-2 PSI Project No Boring No. TABLE 2 Elevations of Top of Rock Alexander City Compressor Station (CS-1) Alexander City, Alabama Boring Depth Surface Elevation (feet) (feet) Top of Rock Elevation (feet) BH BH BH BH BH BH BH BH Note: Surface elevations provided by Ken McDonald with GIE.

M E M O R A N D U M. Mr. Jonathan K. Thrasher, P.E. and Mr. Ian Kinnear, P.E. PSI

M E M O R A N D U M. Mr. Jonathan K. Thrasher, P.E. and Mr. Ian Kinnear, P.E. PSI M E M O R A N D U M TO: FROM: Mr. Mark Schilling Gulf Interstate Engineering Mr. Jonathan K. Thrasher, P.E. and Mr. Ian Kinnear, P.E. PSI DATE: November 11, 2014 RE: Summary of Findings Geotechnical Study