REPORT OF SUBSURFACE EXPLORATION

Transcription

1 REPORT OF SUBSURFACE EXPLORATION GRAND RIVER DAM AUTHORITY HULBERT 69 KV SWITCHING STATION S. 440 Road Hulbert, Cherokee County, Oklahoma ENERCON PROJECT NO. GRDA006 MARCH 7, 2012 PREPARED FOR: C/O ENERCON SERVICES, INC STATE ROAD 434 SUITE 252 LONGWOOD, FLORIDA SUBMITTED BY: ENERCON SERVICES, INC. 500 TOWNPARK LANE SUITE 275 KENNESAW, GEORGIA 30144

2 March 7, 2012 Grand River Dam Authority c/o Enercon Services, Inc State Road 434 Suite 252 Longwood, Florida ENERCON Project No. GRDA006 Attention: Subject: Mr. Kenneth R. Lord, P.E. Report of Subsurface Exploration Hulbert 69 KV Switching Station South 440 Road Hulbert, Cherokee County, Oklahoma Dear Mr. Load: As authorized, Enercon Services, Inc. (ENERCON) has completed a subsurface exploration for the above listed project. The purpose of this exploration was to obtain subsurface data to assist in the design of the proposed substation. The scope of our exploration was established in correspondence and discussions with ENERCON project designers. This report describes the findings from this subsurface exploration and our recommendations. This report was prepared for the exclusive use of Enercon Services, Inc. and their client Grand River Dam Authority (GRDA). Our services were performed in accordance with generally accepted geotechnical engineering practices in the State of Oklahoma. No other warranty, expressed or implied, is made. EXPLORATION METHODOLOGY Subsurface conditions at the site were explored by five soil test borings at the approximate locations shown on Figure 1 Boring Location Plan. ENERCON personnel established the boring locations by estimating right angles and taping distances from existing site features identified from the provided site plan. Some adjustments were made to some of the requested boring locations due to overhead power lines. The revised locations of these borings are shown on the Boring Location Plan. The borings were not located by survey techniques. ENERCON has not been provided with ground surface elevations at the boreholes. The soil test borings were advanced to auger refusal at depths ranging from about 5 to 8 feet below the existing ground surface. Standard penetration testing was performed at the surface and at 5-foot intervals. After auger refusal was encountered, each boring was then advanced utilizing NQ size (approximately 1.9 inches in diameter) rock coring techniques to assess the continuity and character of the refusal materials. Drilling and sampling operations were performed in general accordance with ASTM and geotechnical industry standards. Brief descriptions of the field procedures are included in Appendix A. Soil and rock samples obtained during the exploration were returned to our laboratory and reviewed by a geotechnical engineer. The general descriptions of the soils are summarized on Boring Records in Appendix B. Classification of soils were not based on laboratory testing. Therefore so they should be

3 Hulbert 69KV Switching Station Report of Subsurface Exploration Hulbert, Cherokee County, Oklahoma Page 2 considered approximate. The stratification lines shown on the boring records represent the approximate boundaries between soil types. However, the transitions may be more gradual. Several soil samples and two rock core samples were selected for laboratory resistivity testing. The results of these tests are appended and discussed in a latter section of the report. SITE CONDITIONS The site is a 2.6-acre parcel of land, which is located west of South Road 440 about 0.2 miles south of the intersection of S. Road 440 and W. 775 Road in Cherokee County, Oklahoma. It is located approximately 4 miles south-southeast of the town of Hulbert, Oklahoma. The site is currently a fenced pasture covered with grass and weeds. In the southeast corner of the site is a small pond. We were unable to determine if this was a manmade feature or remnant of a sinkhole. An overhead power line crosses the site in a generally east-west direction through the central portion of the site. Site topography is nearly flat with a gentle slope down to the south. At the time of our exploration, the ground surface was moist to wet. SUBSURFACE CONDITIONS The conditions encountered at each boring location are detailed on the appended Boring Records. Each boring initially encountered a 2 to 3 inch thick layer of topsoil and surface vegetation root material. Below the surficial covering, a zone of cultivated soil was penetrated to a depth of about 3 feet. Cultivated soils are soils that have been loosened and disturbed by past plowing and tilling during agricultural use. These soils were typically described as very soft to firm dark brown clay with topsoil and roots. Several samples of the near surface soils were wet. Standard Penetration Resistance values in the cultivated zone varied from the weight of hammer (i.e. the dead weight of the sampling device and hammer forced the sample through the sampling interval without striking a blow) to 5 blows per foot (bpf). At boring B-3 and B-4, a thin zone of undisturbed residual soils was penetrated below the cultivated soils to a depth of about 4 ½ to 5 feet. Residual soils have been formed in place by weathering of the parent material. These residual soils were described as brown clay and exhibited standard penetration resistance value of 14 bpf. At boring B-1, B-2, and B-5 the cultivated soils extended to the top of weathered limestone. At boring B- 3 and B-4 the weathered limestone was found below the thin layer of residuum. The weathered limestone extended to auger refusal, which was encountered at depths varying from 5 to 8 feet below the existing ground surface. Each boring was advanced using NQ size rock coring techniques. The NQ rock core bit retrieves a sample that is approximately 1.9 inches in diameter. The recovered rock was typically a limestone with some chert lenses. Rock recovery (REC) varied from 55 to 100 percent of the core run length. The Rock Quality Designation () of the runs varied from 31 to 93 percent. Several clay filled voids were detected during coring. No open voids were detected to the depths cored. Groundwater was not encountered in the borings at completion of soil test drilling and prior to rock coring. Rock coring was performed, which that introduced water into the borehole. At completion of the coring, the boreholes were abandoned in place by grouting the boreholes. Therefore, the boreholes could not be checked for stabilized groundwater. Considering the shallow depth of refusal, it is unlikely

4 Hulbert 69KV Switching Station Report of Subsurface Exploration Hulbert, Cherokee County, Oklahoma Page 3 groundwater exists in the soil matrix. The site appears to be susceptible to having temporary perched groundwater on the shallow weathered rock surface. LABORATORY SOIL RESISTIVITY TESTING Portions of soil samples were selected for laboratory soil resistivity testing to be used for grounding design. These samples were submitted to GeoTesting Express for soil resistivity testing using the Wenner Four Electrode Method described in ASTM G-57. The results of these tests are as follows: Boring Number Sample Type Depth (ft) Sample Description Electrical Resistivity, ohm-cm 10,064 B-1 Grab Sample from Moist, brown silty clay with Ground Surface organics B-1 Rock Core 4 Hard light gray limestone *>3.2E+08 B-2 Grab Sample from Moist, brown silty clay with 9,946 Ground Surface organics B-3 Split Spoon Moist, brown silty clay with 15,416 trace organics B-3 Grab Sample from 3 Dry, light gray rock cuttings 1,492 Auger Cuttings B-4 Split Spoon Moist, brown silty clay 5,968 B-4 Split Spoon Moist, brown silty clay 1,343 B-5 Split Spoon Moist, brown silty clay with 4,774 organics B-5 Grab Sample from 5 Dry, light gray rock cuttings 1,831 Auger Cuttings and moist, brown clay B-5** Rock Core 7.5 Hard gray limestone with chert 1.16E+08 *test could not be completed because sample resistance exceeded the capacity of the resistance meter **results may have been influenced by jointing and fractures in specimen GENERAL DESIGN RECOMMENDATIONS Based on the results of our subsurface exploration, it appears that the site can be developed to support the proposed substation from a geotechnical standpoint. However, the presence of an upper layer of loose often wet cultivated soil, clayey residual soils, and the shallow depth to weathered rock and sound rock will impact design and construction. The presence of shallow weathered rock and sound rock will impact mass excavation, utility excavation, and foundation excavation. The premium cost of rock removal will impact the construction budget. The site has been used for agriculture and the upper soils appear to have been loosened by past land cultivation. In their current state, they are not suitable for support of foundations, slabs or pavements. Compaction of the upper cultivated soil zone is recommended to prepare the site for construction. The thickness of the cultivated zone will require that it be undercut and replaced in

5 Hulbert 69KV Switching Station Report of Subsurface Exploration Hulbert, Cherokee County, Oklahoma Page 4 compacted lifts. Considering the moisture content of the material and depending on the prevailing weather at the time of construction, it may be more cost effective to waste the cultivated soil and replace it with suitable borrow. Laboratory testing to determine the expansive characteristics of the clayey residual soils was not performed. This testing was not in the work scope and the thickness of the material is fairly insignificant. Penetration of these materials to the higher quality weathered rock encountered at shallow depths is recommended for shallow foundations. The site area is underlain by limestone rock, which is susceptible to solution activity and formation of voids in the subsurface materials. The voids form from soil migration into the solution opening in the underlying rock. Where these voids collapse, sinkholes form and loss of support can occur to structures supported above them. At the subject site the borings did not detect voids in the soil layer and the depth to rock is fairly uniform. Since structures will be support at or within a few feet of rock, the risk of an undetected soil void resulting in sinkhole formation and loss of foundation support appears to be low. SITE AND SUBGRADE PREPARATION Prior to proceeding with construction operations, the existing surficial grasses and miscellaneous vegetation should be cleared. Heavily organic topsoil should be stripped and wasted off site or used in landscaping areas. The few feet of soil below the topsoil is dark brown and will have a similar appearance to the heavily organic topsoil. This upper soil does not appear to be heavily organic and need not be stripped due to organic content. As mentioned in the GENERAL section of this report, the upper layer of soil has been loosened by past cultivation and will require compaction. We recommend it be removed and replaced at a compaction of at least 95 percent of the maximum dry density of the Standard Proctor (ASTM D-698). At the time of this exploration, the soils were wet to moist and would require drying to permit compaction. Depending on the moisture condition of the soils at the time of construction and the prevailing weather, it may be more cost effective to waste the upper three feet of cultivated soil and replace it with a suitable moisture soil then to dry the existing materials on site. Following the removal of the cultivated soil, the exposed subgrade should be proofrolled with a 20 to 30 ton tandem axle dump truck or similar piece of rubber tired equipment. Proof-rolling consists of applying repeated passes to the subgrade with this equipment. The purpose of the proof-rolling is to identify soft, weak, or excessively wet soils that may be present at the time of evaluation. Unsuitable or unstable materials identified during the subgrade evaluation or proof-rolling operations should be undercut and replaced with compacted fill or stabilized in-place. We do not know if any site development will occur in the area of the small on site pond. The scope of the field exploration did not include evaluation of conditions in this area. If development or filling of the pond is planned, additional evaluation of this area may be warranted.

6 Hulbert 69KV Switching Station Report of Subsurface Exploration Hulbert, Cherokee County, Oklahoma Page 5 EARTHWORK After subgrade evaluation and subgrade preparation measures have been implemented, the site may be brought to the design subgrade levels with structural fill. Structural fill or backfill should be clean soil, free of excessive organic matter. Material containing rocks or stones greater than 3 inches in diameter should not be used. Structural fill should be placed in maximum 6 to 8 inch loose lifts, and compacted to at least 95 percent of the soil s maximum dry density as determined by the Standard Proctor Compaction Test (ASTM D-698). Backfill in trenches or other confined spaces, where light portable compaction equipment is required, should be placed in maximum lift thicknesses of 4 inches and compacted to at least the same level of compaction. All fill material should be placed in horizontal lifts and adequately keyed into the existing subgrade. Crushed stone backfill discussed in this report should meet the requirements Subsection , Aggregate for Aggregate Base (Type A, Type B, or Type C) of the Oklahoma Department of Transportation 2009 Standard Specifications for Highway Construction. Crushed stone backfill should be compacted to at least 95 percent of the maximum dry density of Modified Proctor (ASTM D-1557). During fill placement, field density tests should be performed by a qualified soils technician working under the direction of a geotechnical engineer to check that the degree of compaction being achieved is in accordance with project specifications. FOUNDATIONS We understand that the substation structures will be supported on both shallow spread footings and drilled piers. Due the condition of the upper cultivated soils and thin layer of clayey residual soils encountered in the borings, shallow foundations should penetrate these materials and bear on the underlying weathered rock. Alternately the foundations may be over-excavated down to the weathered rock and backfilled with compacted-crushed stone or additional concrete. An allowable bearing capacity of 6,000 psf can be used for foundations bearing on the weathered rock or on compacted crushed stone underlain directly by weathered rock. A minimum foundation width of 3 feet is recommended for this bearing capacity. An embedment depth of 2 feet is recommended as a precaution against frost heave. It is recommended that a geotechnical engineer evaluate all foundation excavations to assess that conditions are similar to those encountered in the borings and that the bearing soils are capable of supporting the design bearing pressures. If the foundation subgrades are to be over-excavated and backfilled, the engineer should evaluate the base of the undercut. Drilled piers should be extended at least 2 feet into the weathered rock or sound rock. Support can be obtained through end bearing, side frictional resistance or both. For end bearing in weathered rock an allowable capacity of 6000 psf can be assumed. For end bearing in competent rock, an allowable end bearing capacity of up to 40,000 psf can be used. For bearing pressures greater than 6,000 psf, evaluation of drilled percussion holes that extend 2 pier diameters below the base of the drilled pier should be performed by a geotechnical engineer. The geotechnical engineer should use a scratch rod to confirm the underlying materials are satisfactory for support of the anticipated foundation stresses. For side frictional resistance we recommend the length of pier in soil be ignored. The portion of the pier in weathered rock can be designed assuming a side friction of 1,000 psf for compressive loads and 700 psf for tension loads. The portion of the pier below auger refusal in sound rock can be designed assuming a side

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8 FIGURE

9 B B CL Existing Overhead Power Lines 21 B-3 B B Hulbert 69 KV Switching Station S 440 Road and W 775 Road Hulbert, Oklahoma LEGEND: Approximate Boring Location Scale: 1 = 54± Source: Soil Boring Location Plan, GRDA (dated 09/09/2011) Figure 1 Boring Location Plan ENERCON Job No.: GRDA006

10 APPENDIX A TEST PROCEDURES

11 TEST PROCEDURES The general field procedures employed by Enercon Services, Inc. (ENERCON), are summarized in the American Society for Testing and Materials (ASTM) Standard D420 "Investigating and Sampling Soil and Rock". This recommended practice lists recognized methods for determining soil and rock distribution and groundwater conditions. These methods include geophysical and in-situ methods as well as borings. Standard Drilling Techniques To obtain subsurface samples, borings are drilled using one of several alternate techniques depending upon the subsurface conditions. Some of these techniques and typical drilling methods used are presented in the following paragraphs: In Soils: a) Continuous hollow stem augers. b) Rotary borings using roller cone bits or drag bits, and water or drilling mud to flush the hole. In Rock: a) Core drilling with diamond-faced, double or triple tube core barrels. b) Core boring with roller cone bits. Hollow Stem Augering: A hollow stem augers consists of a hollow steel tube with a continuous exterior spiral flange termed a flight. The auger is turned into the ground, returning the cuttings along the flights. The hollow center permits a variety of sampling and testing tools to be used without removing the auger. Rotary Borings: Rotary boring uses a high speed revolving cutter and circulating liquid or air to remove the cuttings. Typically, water or drilling mud is used to remove the cuttings. Several types of bits are used to penetrate through the soil mass, including tri-cone roller bits for hard soil/soft rock. Core Drilling: Soil drilling methods are not normally capable of penetrating through hard cemented soil, weathered rock, coarse gravel or boulders, thin rock seams, or the upper surface of sound, continuous rock. Materials that cannot be penetrated by auger or rotary soil-drilling methods at a reasonable rate are designated as refusal materials. Core drilling procedures are required to penetrate and sample refusal materials. Prior to coring, casing may be set in the drilled hole through the overburden soils to keep the hole from caving and to prevent excessive water loss. The refusal materials are then cored according to ASTM D2113 using a diamond-studded bit fastened to the end of a hollow, double or triple tube core barrel. This device is rotated at high speeds and the cuttings are brought to the surface by circulating water. Core samples of the material penetrated are protected and retained in the swivel-mounted inner tube. Upon completion of each drill run, the core barrel is brought to the surface, the core recovery is measured, and the core is placed in boxes for storage and transportation to our laboratory. Sampling and Testing in Boreholes Several techniques are used to obtain samples and data in soils in the field, however the most common methods in this area are: a) Standard Penetrating Testing b) Undisturbed Sampling c) Dynamic Cone Penetrometer Testing d) Water Level Readings

12 The procedures utilized for this project are presented below. Standard Penetration Testing: At regular intervals, the drilling tools are removed and soil samples obtained with a standard 2 inch diameter split tube sampler connected to an A or N-size rod. The sampler is first seated 6 inches to penetrate any loose cuttings, then driven an additional 12 inches with blows of a 140 pound safety hammer falling 30 inches. Generally, the number of hammer blows required to drive the sampler the final 12 inches is designated the "penetration resistance" or "N" value, in blows per foot (bpf). The split barrel sampler is designed to retain the soil penetrated, so that it may be returned to the surface for observation. Representative portions of the soil samples obtained from each split barrel sample are placed in jars, sealed and transported to our laboratory. The standard penetration test, when properly evaluated, provides an indication of the soil strength and compressibility. The tests are conducted according to ASTM Standard D1586. The depths and N-values of standard penetration tests are shown on the Boring Records. Split barrel samples are suitable for visual observation and classification tests but are not sufficiently intact for quantitative laboratory testing. Water Level Readings: Water table readings are normally taken in the borings and are recorded on the Boring Records. In sandy soils, these readings indicate the approximate location of the hydrostatic water table at the time of our field exploration. In clayey soils, the rate of water seepage into the borings is low and it is generally not possible to establish the location of the hydrostatic water table through short term water level readings. Also, fluctuation in the water table should be expected with variations in precipitation, surface runoff, evaporation, and other factors. For long-term monitoring of water levels, it is necessary to install piezometers. The water levels reported on the Boring Records are determined by field crews immediately after the drilling tools are removed, and several hours after the borings are completed, if possible. The time lag is intended to permit stabilization of the groundwater table which may have been disrupted by the drilling operation. Occasionally the borings will cave-in, preventing water level readings from being obtained or trapping drilling water above the cave-in zone. The cave-in depth is measured and recorded on the Boring Records. Boring Records The subsurface conditions encountered during drilling are reported on a field boring records prepared by the Driller or an ENERCON representative. The records contains information concerning the boring method, samples attempted and recovered, indications of the presence of coarse gravel, cobbles, etc., and observations of groundwater. It also contains the field representative's interpretation of the soil conditions between samples. Therefore, these boring records contain both factual and interpretive information. After the drilling is completed, a geotechnical engineer or geologist classifies the soil samples and prepares the final Boring Records, which are the basis for our evaluations and recommendations. Soil Classification Soil classifications provide a general guide to the engineering properties of various soil types and enable the engineer to apply his past experience to current problems. In our investigations, samples obtained during drilling operations are examined in our laboratory and visually classified by an engineer. The soils are classified according to consistency (based on number of blows from standard penetration tests), color and texture. These classification descriptions are included on our Boring Records. The Key to Symbols and Classifications in Appendix B presents criteria that are typically used in the classification and description of soil and rock samples for preparation of Boring Records.

13 APPENDIX B BORING RECORDS LABORATORY TEST REPORTS KEY TO SYMBOLS AND CLASSIFICATIONS

14 BORING RECORD BORING NO.: B-1 PROJECT NOTES Hulbert 69 KV Switching Station Borehole backfilled and grouted after delayed groundwater reading LOCATION S. 440 Road and W 775 Road, Hulbert, OK MANUFACTURERS DESIGNATION OF DRILL RIG SHEET NUMBER DRILLING AGENCY CME-550, Auto Hammer 1 OF 1 Mohawk Drilling, Inc. DRILLING METHOD Hollow Stem Auger DIRECTION OF HOLE Vertical DEPTH TO GROUND WATER AT TIME OF BORING Not Encountered ASTM D-1586 DEPTH TO GROUND WATER - DELAYED READING Not Obtained BOREHOLE DIAMETER 6 IN STARTED COMPLETED SAMPLING METHOD Split Spoon and NQ Rock DATE OF BOREHOLE ELEVATION OF TOP OF BOREHOLE Not Provided 2/7/2012 2/9/2012 DEPTH (FT) CLASSIFICATION OF MATERIALS 2 inches Top Soil Cultivated Soil - Very Soft dark brown silty CLAY with sand SAMPLE TYPE BOX OR SAMPLE NO. SS 1 ROCK RESULT REMARKS 0.25 tsf unconfined compression estimated with pocket penetrometer BLOWS PER 6" INCREMENT SPT N (BPF) Weathered Limestone sampled as very hard tan brown fine CLAY Auger Refusal at 4 feet SS 2 50 / 0 in Hard to moderately hard gray limestone with chert NQ REC Clay seam 7 to 8 feet Highly fractured 8 to 10 feet NQ REC REC 76 Highly fractured and weathered 14 to 15 feet NQ Highly fractured 18 to 20 feet 21.0 Coring terminated at 20 feet ENERCON Project #WALTON051

15 BORING RECORD BORING NO.: B-2 PROJECT NOTES Hulbert 69 KV Switching Station Borehole backfilled and grouted after completion of drilling LOCATION S. 440 Road and W 775 Road, Hulbert, OK MANUFACTURERS DESIGNATION OF DRILL RIG SHEET NUMBER DRILLING AGENCY CME-550, Auto Hammer 1 OF 1 Mohawk Drilling, Inc. DRILLING METHOD Hollow Stem Auger DIRECTION OF HOLE Vertical DEPTH TO GROUND WATER AT TIME OF BORING Not Encountered ASTM D-1586 DEPTH TO GROUND WATER - DELAYED READING Not Obtained BOREHOLE DIAMETER 6 IN STARTED COMPLETED SAMPLING METHOD Split Spoon and NQ Rock Core DATE OF BOREHOLE ELEVATION OF TOP OF BOREHOLE Not Provided 2/7/2012 2/9/2012 DEPTH (FT) CLASSIFICATION OF MATERIALS 3 inches of Top Soil Cultivated Soil - Firm brown silty CLAY, moist SAMPLE TYPE BOX OR SAMPLE NO. SS 1 ROCK RESULT REMARKS 1.0 tsf unconfined compression estimated with pocket penetrometer BLOWS PER 6" INCREMENT SPT N (BPF) Weathered Limestone - Sampled as very hard tan brown CLAY Auger Refusal at 5 feet Hard gray limestone with weathered joints Very hard fractured limestone with chert SS 2 50 / 0 in NQ REC Very slow coring rate (2 in./hr.) from 14 to 14.2 feet 15.0 Coring terminated at 14.2 feet ENERCON Project #WALTON051

16 BORING RECORD BORING NO.: B-3 PROJECT NOTES Hulbert 69 KV Switching Station Borehole backfilled after completion of drilling LOCATION S. 440 Road and W 775 Road, Hulbert, OK MANUFACTURERS DESIGNATION OF DRILL RIG SHEET NUMBER DRILLING AGENCY CME-550, Auto Hammer 1 OF 2 Mohawk Drilling, Inc. DRILLING METHOD Hollow Stem Auger DIRECTION OF HOLE Vertical DEPTH TO GROUND WATER AT TIME OF BORING Not Encountered ASTM D-1586 DEPTH TO GROUND WATER - DELAYED READING Not Obtained BOREHOLE DIAMETER 6 IN STARTED COMPLETED SAMPLING METHOD Split Spoon and NQ Rock Core DATE OF BOREHOLE ELEVATION OF TOP OF BOREHOLE Not Provided 2/7/2012 2/8/2012 DEPTH (FT) CLASSIFICATION OF MATERIALS 2 inches of Top Soil Cultivated Soil - Soft red brown sandy CLAY, wet SAMPLE TYPE SS BOX OR SAMPLE NO. 1 ROCK RESULT REMARKS 0.75 tsf unconfined compression estimated with pocket penetrometer BLOWS PER 6" INCREMENT SPT N (BPF) Residuum - Very stiff dark brown CLAY, moist Weathered Limestone - Sampled as very tan brown CLAY SS tsf unconfined compression estimated with pocket penetrometer / 1 in 8.0 Auger Refusal at 8 feet Moderately hard to hard light gray limestone with weathered joints REC NQ Very hard light gray limestone Coring terminated at 20 feet REC NQ REC NQ ENERCON Project #WALTON051

17 BORING RECORD BORING NO.: B-4 PROJECT NOTES Hulbert 69 KV Switching Station Borehole backfilled and grouted after delayed groundwater reading LOCATION S. 440 Road and W 775 Road, Hulbert, OK MANUFACTURERS DESIGNATION OF DRILL RIG SHEET NUMBER DRILLING AGENCY CME-550, Auto Hammer 1 OF 1 Mohawk Drilling, Inc. DRILLING METHOD Hollow Stem Auger DIRECTION OF HOLE Vertical DEPTH TO GROUND WATER AT TIME OF BORING Not Encountered ASTM D-1586 DEPTH TO GROUND WATER - DELAYED READING Not Obtained BOREHOLE DIAMETER 6 IN STARTED COMPLETED SAMPLING METHOD Split Spoon and NQ Rock Core DATE OF BOREHOLE ELEVATION OF TOP OF BOREHOLE Not Provided 2/7/2012 2/9/2012 DEPTH (FT) CLASSIFICATION OF MATERIALS 2 inches of Top Soil Cultivated Soil - Very soft brown CLAY, wet, with topsoil and roots SAMPLE TYPE BOX OR SAMPLE NO. SS 1 ROCK RESULTS REMARKS 0.50 tsf unconfined compression estimated from pocket penetrometer BLOWS PER 6" INCREMENT 1 WH WH SPT N (BPF) Residuum - Stiff dark brown CLAY, moist Weathered Limestone - Sampled as very hard tan brown CLAY SS tsf unconfined compression estimated from pocket penetrometer Auger refusal at 8 feet 9.0 Hard light gray medium to fine grained limestone NQ REC Coring terminated at 18 feet ENERCON Project #GRDA006

18 BORING RECORD BORING NO.: B-5 PROJECT Hulbert 69 KV Switching Station NOTES Borehole backfilled and grouted after completion of drilling S. 440 Road and W 775 Road, Hulbert, OK MANUFACTURERS DESIGNATION OF DRILL RIG SHEET NUMBER DRILLING AGENCY CME-550, Auto Hammer 1 OF 1 Mohawk Drilling, Inc. DRILLING METHOD Hollow Stem Auger DIRECTION OF HOLE Vertical DEPTH TO GROUND WATER AT TIME OF BORING Not Encountered ASTM D-1586 DEPTH TO GROUND WATER - DELAYED READING Not Obtained BOREHOLE DIAMETER 6 IN STARTED COMPLETED SAMPLING METHOD Split Spoon and NQ Rock Core DATE OF BOREHOLE ELEVATION OF TOP OF BOREHOLE Not Provided 2/7/2012 2/8/2012 DEPTH (FT) CLASSIFICATION OF MATERIALS 3 inches of Top Soil Cultivated Soil - Soft dark brown CLAY with roots SAMPLE TYPE BOX OR SAMPLE NO. SS 1 ROCK RESULT REMARKS 1.5 tsf unconfined compression estimated with pocket penetrometer BLOWS PER 6" INCREMENT SPT N (BPF) Weathered Limestone- Sampled as very hard tan brown CLAY 5.0 Auger Refusal at 5 feet Hard coarse grained gray limestone with weathered joints REC. NQ clay sem 8 to 9 feet clay seam 9.5 to 10 feet Very hard gray fine grained limestone with chert REC NQ REC NQ REC NQ highly fractured from 18 to 19 feet 21.0 Coring terminated at 20 feet ENERCON Project #GRDA006

19 Client: Enercon Project: Hulbert Switching Station Location: Hulbert Oklahoma GTX#: 1793 Test Date: thru Tested By: jm Checked By: MCM Laboratory Measurement of Soil Resistivity Using the Wenner Four-Electrode Method by ASTM G 57 Boring ID Sample ID Depth, ft. Sample Description Electrical Resistivity, ohm-cm Electrical Conductivity, (ohm-cm) -1 B Ground Moist, brown silt with organics 10, E-05 B Ground Moist, brown silt with organics 9, E-04 B " Moist, brown silt with organics 15, E-05 B-3 Rock Dust From Auger Recovery 3' Dry, ligth gray rock dust 1, E-04 B ' Moist, brown silt with organics 5, E-04 B ' Moist, brown silt with organics 1, E-04 B ' Moist, brown silt with organics 4, E-04 B-5 Rock Dust From Auger Recovery 5' Dry, light gray rock dust and Moist, brown clay 1, E-04 Notes: Electrical Conductivity is calculated as inverse of Electrical Resistivity (per ASTM G 57) Test conducted in standard laboratory atmosphere: F Samples B-1 Rock Dust at 4' and B-3 at 5' could not be run due to small amount of recovery

20 Client: Enercon Project: Hulbert 69 KV Switching Station Location: Hulbert, Oklahoma GTX#: 1793 Tested By: jm Test Date: 02/21/12 Checked By: MCM Laboratory Measurement of Rock Resistivity Using the Two-Electrode Method by ASTM G 187 Boring ID Sample ID Depth, ft Sample Description Electrical Resistivity, ohm-cm Electrical Conductivity, (ohm-cm) -1 B-1 * --- 4' Rock Core >328,614,237 >3.04E-09 B-5 ** ' Rock Core 1.16E E-09 Comments: Test Equipment: Nilsson Model 400 Resistance Meter Test conducted in standard laboratory atmosphere: F Test specimen soaked in distilled water for 90 minutes prior to testing. * Sample resistance exceeded the capacity of the resistance meter. ** Sample resistance may be influenced by cracks and shear planes present in material. See Photos.

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