inch (12.4 cm) reaming bit (i.e., must be <5 inches [12.7 cm] to fit inside the casing), requiring 2–4 days.Drilling at the Double Trouble site (39°53′44.732″N, 74°13′23.346″W; elevation 36.8 ft (11.2 m); Toms River USGS 7.5 minute quadrangle; Berkeley Township, Ocean County, New Jersey) began on 10 October 2008. Drilling operations were superintended by Gene Cobbs III, Head Driller, USGS Eastern Earth Surface Processes Team (EESPT). Jeff Grey was the assistant driller. The Double Trouble State Park (Mark Pitchell, Superintendent) provided space, water, and electricity. The drillers arrived in the morning of 9 October and began rigging up. An onsite water well drilled by the USGS provided water. On 9 October, a field trailer was set up as a portable laboratory with hookups to the park's electricity. A Canon Power Shot G5 Zoom digital zoom camera (7.8–22 mm lens; 5 megapixel resolution), Macintosh Macbook Pro, and the Delaware Geological Survey photography stand were set up to photograph 2 ft (0.61 m) core segments; the camera's default settings with no flash were used.
All cores were measured in feet (all depths are given in feet below land surface with metric conversions provided). We continue to adopt the ODP convention of top justifying depths for intervals with incomplete recovery for all field notes and photos.
The first core was obtained on 10 October using a Christensen 94 mm (HQ) system, 4.5 inch Christensen CH bit. For unconsolidated sands, an extended "snout" shoe was used to contact the sample 1.5–2.5 inches (3.8–6.4 cm) ahead of the bit; core diameter is 2.5 inches (6.5 cm) with a rock shoe and 2.1 inches (5.3 cm) with the snout shoe. The uppermost 5 ft (1.5 m) was augured away while setting surface casing. The first core was obtained at 0850 h on 10 October with 1.2 ft (0.4 m) recovered (5–6.2 ft; 1.5–1.9 m) from 5 ft (1.5 m) run in very loose quartz sand. The second run (10–15 ft; 3–4.6 m) recovered 1.4 ft (0.4 m), also in very loose sand. The drillers put on the extended shoe to try to improve recovery, but poor recovery continued. Run 3 (15–20 ft; 4.6–6.1 m) had 40% recovery, and Run 4 (20–25 ft; 6.1–7.6 m) recovered 1.7 ft (0.5 m) of medium to very coarse sand. Run 5 (25–30 ft; 7.6–9.1 m) recovered 4.3 ft (1.3 m) in slightly siltier sand. Fast coring with poor to moderate recovery, especially in very wet coarser sands, continued through the day in the Cohansey Formation. Examples of poor recovery include Run 6 (30–35 ft; 9.1–10.7 m), which recovered 1 ft (0.3 m) of soupy coarse sand, Run 9 (45–50 ft; 13.7–15.2 m), which recovered 0.8 ft (0.2 m) of medium sand, and Run 12 (60–65 ft; 18.3–19.8 m), which recovered only 1.5 ft (0.5 m) of sand. The drillers intended to set surface casing in the first clay encountered. A fine-grained bed encountered the nearby Berkeley Township MUA hole at 50 ft (15.2 m) was not present at Double Trouble. The day ended at 70 ft (21.3 m) depth with 22.55 ft (7.8 m) recovered from 65 ft (19.8 m) drilled (39.3% recovery).
Recovery on 11 October improved in generally medium to coarse sand with 30 ft (9.1 m) (Runs 14–18, 70–100 ft; 21.3–30.5 m) drilled and 18.8 ft (5.7 m) recovered in the morning. Sticky clay at the bottom of Run 19 (100–105 ft; 2.3 ft recovered [30.5–32.0 m; 0.7 m]) blocked the bit and outer core barrel, preventing the inner core barrel from latching into place. The rods were pulled in order to clean off the clay. Normal coring resumed at 1500 h from 105 to 110 ft (Run 20, 32.0 to 33.5 m) with 4.3 ft (1.3 m) of recovery. Run 21 (110–120 ft; 33.5–36.6 m) is believed to have slipped out of the core barrel and only 0.1 ft (2.5 cm) of core was recovered. The day ended at 120 ft (36.6 m) depth with 26.15 ft (8.0 m) recovered from 50 ft (15.2 m) drilled (52% recovery).
On Sunday, 12 October, the drillers attempted to recover the rest of the core from Run 21. Run 21 recovered 0.65 ft (0.2 m), and Run 22 (120–125 ft; 36.6–38.1 m) recovered 4.75 ft (1.4 m; 95% recovery). Run 23 (125–130 ft; 38.1–39.6 m) recovered 4.6 ft (1.4 m), Run 24 recovered 3.7 ft (1.1 m; 64% recovery) from 130 to 135 ft (39.6 to 41.1 m), and Run 25 recovered 3 ft (0.9 m; 60% recovery) from 135 to 140 ft (41.1 to 42.7 m). Recovery was poor for Runs 26, 27, and 28, with 0.5 ft (0.2 m) from 140 to 150 ft (42.7 to 45.7 m), 0.9 ft (0.3 m) from 150 to 152 ft (45.7 to 46.3 m), and 0.35 ft (0.1 m) from 152 to 160 ft (46.3 to 483.8 m), respectively. Run 29 (160–165 ft; 48.8–50.3 m) recovered 2.7 ft (0.8 m; 54% recovery). Recovery improved to 96% on Run 30 (165–170 ft; 50.3–51.8 m). For Run 31, recovery was 90% (170–180 ft; 51.8–54.9 m; 9 ft [2.7 m] recovered), ending in granuliferous sand. The day ended at 180 ft (54.9 m) depth with 34.3 ft (10.5 m) recovered from 60 ft (18.3 m) drilled (57% recovery).
On Monday 13 October, the drillers flushed away the caved gravel penetrated at the end of the previous day. On the first run (Run 32; 180–182 ft; 54.9–55.5 m), the extended shoe could only penetrate 2 ft (0.6 m) into gravels, and 1.7 ft (0.5 m) was recovered. Run 33 (182–190 ft; 55.5–57.9 m) only recovered 0.7 ft (0.2 m) from gravels. On the next run the rods became sand locked and the drillers were forced to pull the rods. It took 2 hr to free the inner core barrel from the drill rod. The drillers had not advanced the rods below 190 ft (57.9 m); the gravels caving in the hole prevented coring. After clearing the barrel, the drillers reran the rods. They decided to run heavy mud in the hole and let it settle overnight. Examination of the gamma log from the nearby Berkeley Township MUA hole suggested that the gravels were thin (~5–6 ft; 1.5–1.8 m), which suggested that we may have penetrated the base of the gravels. Recovery for the day was 2.4 ft (0.7 m) from 10 ft (3.0 m) drilled (24%).
The drillers decided to run 6 inch (15.2 cm) PVC casing on Tuesday 14 October to case off the caving gravels. This depth is similar to where casing was set during drilling of the Transco Double Trouble well (drilled in 1951) that was cased at 207 ft (63.1 m). Despite repeated attempts on 14 and 15 October, the casing would not penetrate below 40 ft (12.2 m) in the Cohansey Formation sands. The drillers obtained 5 inch (12.7 cm) PVC casing on Thursday 16 October and ran it through the 6 inch (15.2 cm) casing to the bottom of the hole at 188 ft (57.3 m), successfully sealing off the Cohansey Formation sands and the caving gravels at ~180–185 ft (54.9–56.4 m).
The drillers ran the rods to the bottom of the hole on the morning of Friday 17 October. Coring resumed at 1000 h with good recovery in silty fine-to-medium sand. The drillers used the 10 ft (3.0 m) barrel for the day, although most runs were cut short because of difficult penetration. Run 40 (225–226 ft; 68.6–68.9 m) was sand locked, but the drillers were able to work the barrel free. Two groups of undergraduate students came to visit the site. The day ended at 250 ft (76.2 m; Run 43) depth with 46.9 ft (14.3 m) recovered from 60 ft (18.3 m) drilled (78% recovery).
Drilling on Saturday 18 October went very well. Ten foot (3.0 m) runs were undertaken between 250 and 310 ft (76.2 and 94.5 m), with recoveries of 85%, 37%, 91%, 93%, 98%, and 96%. A 7 ft (2.1 m) run was taken between 310 and 317 ft (94.5 and 96.6 m), with 4.8 ft (1.5 m) recovered. The next 3 ft (0.9 m) run recovered 0.9 ft (0.3 m), which was indurated in places. In the final run of the day from 320 to 330 ft (97.5 to 100.6 m), 6.1 ft (1.9 m) was recovered. The day ended at 330 ft (100.6 m) depth with 61.8 ft (18.8 m) recovered from 80 ft (24.4 m) drilled (77% recovery).
Cool (~45°F) temperatures greeted the drillers on Sunday 19 October. The first run (330–340 ft; 100.6–103.6 m) was blocked off by indurated sandy clay and only recovered 3.2 ft (1.0 m). The next run (340–345 ft; 103.6–105.2 m) went 5 ft (1.5 m) in alternating sands and indurated zones, recovering 2.0 ft (0.6 m) of solid core and 3 ft (0.9 m) of slop from adding the rods; the base of the run was indurated and had blocked off the core. The slop was discarded. The drillers shortened the shoe. The next run (345–350 ft; 105.2–106.7 m) was also blocked off by an indurated zone and recovered 2.6 ft (0.8 m). The drillers shortened the shoe to just shy of a rock shoe. Run 56 (350–337 ft; 106.7–108.8 m), Run 57 (357–360 ft; 108.8–109.7 m), and Run 58 (360–365 ft; 109.7–111.3 m) recovered 2.4, 1.35, and 2.2 ft (0.7, 0.4, and 0.7 m), respectively, as alternating hard and soft layers hindered recovery. The appearance of clay helped recovery on Run 59 (365–370 ft, 3.1 ft; 111.3–112.8 m, 0.9 m), Run 60 (370–375 ft, 3.4 ft; 112.8–114.3 m, 1.0 m), and Run 61 (375–380 ft, 4.1 ft; 114.3–115.8 m; 1.2 m). We returned to 10 ft cores on Run 62 (380–390 ft; 115.8–118.9 m) and Run 63 (390–400 ft; 118.9–121.9 m) and cored 10 ft (3.0 m), recovering 7.3 and 2.7 ft (2.2 and 0.8 m), respectively. Run 63 blocked off from a clay layer and major change in lithology. The day ended at 400 ft (121.9 m) depth with 34.35 ft (10.5 m) recovered from 70 ft (21.3 m) drilled (49% recovery).
On 20 October, the drillers ran 3 ft (0.9 m) on Run 64 to capture the possible contact with the upper Shark River Formation, but surprisingly ran back into sands of the Toms River Member. Recovery improved on Run 65 (2.8 ft from 403 to 406 ft; 0.9 m from 122.8 to 123.7 m) and Run 66 (2.85 from 406 to 410 ft; 0.9 m from 123.7 to 125.0 m) as the sediments became clayier. The next run (Run 67; 410–415 ft; 125.0–126.5 m) recovered water-rich sands with surprisingly good recovery (3.5 ft; 1.1 m). Run 68 (415–420 ft; 126.5–128.0 m) provided excellent (4.45 ft; 1.4 m) recovery of sands and a spectacular contact. Recovery dropped on Run 69 (420–425 ft, 1.55 ft; 128.0–129.5 m, 0.5 m) and Run 70 (425–430 ft, 3.6 ft; 129.5–131.1 m, 1.1 m) as we ran back into granuliferous sands. The drillers ran 10 ft (3.0 m) on Run 71 (430–440 ft; 131.1–134.1 m), recovering 2.45 ft (0.7 m). The day ended at 440 ft (134.1 m) depth with 22.4 ft (6.8 m) recovered from 40 ft (12.2 m) drilled (56% recovery).
On 21 October, the first run (Run 72) recovered 2.5 ft (0.8 m) of 10 ft (3.0 m). Recovery improved on the next two runs (Run 73 [450–460 ft; 137.2–140.2 m] and Run 74 [460–470 ft; 140.2–143.3 m]): 9.8 and 8.4 ft (3.0 and 2.6 m), respectively. Run 76 originally cored the interval 480–485 ft (146.3–147.8 m). The drillers recovered no core, as the core slipped out of the barrel. They went back and drilled 5 ft (1.5 m) more (485–490 ft; 147.8–149.4 m) and recovered 10 ft (3.0 m). The entire core is logged as Run 76. Run 77 again fell out of the bottom of the barrel, and only 4.5 ft (1.4 m) was originally recovered. On the next run (Run 78; 500–505 ft; 152.4–153.9 m) much more than 5 ft (1.5 m) was recovered, and we placed the upper 2.6 ft (0.8 m) into Run 77 and the rest (4.8 ft; 1.5 m) into Run 78. The day ended at 510 ft (155.4 m) depth with 53.1 ft (16.2 m) recovered from 70 ft (21.3 m) drilled (75.9% recovery). The drillers pulled up 70 ft (21.3 m) overnight because of swelling clays.
On 22 October, the drillers ran the rods back into the hole, but the inner core barrel became stuck. They eventually freed the barrel by rotating the rods and circulating mud. When the inner barrel surfaced at 1000 h, it was covered with sticky clay scraped off of the hole while the rods were lowered. The drillers drilled from 510 to 520 ft (Run 80; 155.4 to 158.5 m) and had difficulty freeing the inner core barrel; by pumping and twisting, they worked the inner barrel free but almost disengaged the overshot. The core arrived safely at the surface at 1200 h with full recovery. The drillers noticed that the quad latch was slightly wobbly. Run 81 (520–530 ft; 158.5–161.5 m) was made without incident, recovering 8.9 ft (2.7 m); Run 82 (530–539.5 ft; 161.5–164.4 m) picked up the 1 ft (0.3 m) lost on the previous run. We adjusted the depths in the field; photos and labels reflect recovery of 10.5 ft (3.2 m) from 529 to 539.5 ft (161.2 to 164.4 m). Run 83 ran 10.3 ft (3.1 m; 539.5–549.8 ft; 164.4–167.6 m) and recovered 9.9 ft (3.0 m). The day ended at 549.8 ft (167.6 m) depth with 39.2 ft (11.9 m) recovered from 39.8 ft (12.1 m) drilled (98% recovery).
On 23 October, drilling went exceptionally well. The lower Shark River Formation clay-silt cored very easily, allowing for exceptional recovery. Run 84 recovered 10.2 ft (3.1 m; 100% recovery) between 549.8 and 560 ft (167.6 and 170.7 m). Recovery was 92% from 560 to 570 ft (170.7 to 173.7 m; Run 85), 99% from 570 to 580 ft (173.7 to 176.8 m; Run 86), 98% from 580 to 590 ft (176.8 to 179.8 m; Run 87), 90% from 590 to 600 ft (179.8 to 182.9 m; Run 88), and 89% from 600 to 609 ft (182.9 to 185.6 m; Run 89). The drillers drilled to 610 ft (185.9 m) to finish the rod and try and retrieve the 1 ft (0.3 m) lost in the last run. They recovered 4 ft (1.2 m) of core. The bottom 2 ft (0.6 m) was added to the previous run, making recovery 100% for 600–610 ft (182.9–185.9 m). The top 2 ft (0.6 m) was labeled as 606–608b (184.7–185.3 m) until the higher cores can be corrected. The day ended at 610 ft (185.9 m) depth with 60.1 ft (18.3 m) recovered from 60.2 ft (18.3 m) drilled (99.8% recovery). The drillers pulled up 160 ft (48.8 m) of rods at the end of drilling.
On 24 October, the drillers ran the 160 ft (48.8 m) of rods that were removed the previous evening. They cleaned out the inner core barrel, pumped the hole, and commenced drilling at 1130 h. Run 91 (610–620 ft, 185.9–189.0 m) recovered 5.85 ft (1.8 m). The next run (Run 92, 620–627 ft; 189–191.1 m) cored 7 ft (2.1 m) and recovered 7.65 ft (2.3 m). The top of this core was probably left in the hole from the previous run. Run 93 recovered 4.05 ft (1.2 m) from 627 to 630 ft (191.1 to 192.0 m). Run 94 recovered only 5.55 ft (1.7 m) from 630 to 640 ft (192 to 195 m). The final run of the day (Run 95, 640–647 ft; 195.1–197.2 m) recovered 7.2 ft (2.2 m). The day ended at 647 ft (197.2 m) with 30.3 ft (9.2 m) recovered from 37 ft (11.3 m) drilled (82% recovery).
On 25 October, drilling from 647 to 655 ft (197.2 to 199.6 m; Run 96) recovered 4.3 ft (1.3 m), whereas the next run from 655 to 660 ft (199.6 to 201.2 m; Run 97) recovered 4.3 ft (1.3 m). On the following run, from 660 to 670 ft (201.2 to 204.2 m; Run 98), the drillers had problems catching the core. When the core was brought to the surface, 10.2 ft (3.1 m) was recovered. From 670 to 680 ft (204.2 to 207.3 m; Run 99), 8.1 ft (2.5 m) was recovered. Run 100 went 9 ft (2.7 m) with 8.5 ft (2.6 m) recovered. After the next run was completed from 688.5 to 698.5 ft (209.9 to 212.9 m; Run 101), the core fell out of the shoe. Recovery was excellent (92%), and the upper 2.1 ft (0.6 m) (688.5–690.6 ft; 209.9–210.5 m) and lower 1.3 ft (0.4 m; 696–697.3 ft; 212.1–212.5 m) were recovered in place, but the core in between is not in place. The final run of the day was from 698.5 to 708 ft (212.9 to 215.8 m; Run 102). The 10 ft (3.0 m) run could not be completed, as there was 0.5 ft (0.2 m) of core left in the hole from the last run. Recovery from this run was 9.5 ft (2.9 m). The day ended at 708 ft (215.8 m) depth with 55.1 ft (16.8 m) recovered from 60 ft (18.3 m) drilled (91.8% recovery).
The drillers ran the rods back into the hole and started drilling on the morning of 26 October. The first run (708–719 ft; 215.8–219.2 m) had almost full recovery (10.7 ft; 3.3 m). The second run (Run 104, 719–729.5 ft; 219.2–222.4 m) initially pulled 5.2 ft (1.6 m). The drillers went back in the hole for Run 105 (729.5–735 ft; 222.4–224.0 m) and recovered 10.5 ft (3.2 m). The core was apportioned between Runs 104 (5.1 ft; 1.6 m) and 105 (5.4 ft; 1.6 m). Drillers encountered problems with sticking rods, and they ceased drilling. They pulled all rods, cleaned the sticky clays off the outside of the rods, and put all but 60 ft (18.3 m) back in the hole, using the headlights of their truck to finish operations. The day ended at 735 ft (224.0 m) depth with 26.4 ft (8.0 m) recovered from 27 ft (8.2 m) drilled (98% recovery).
On the morning of 27 October, drillers added the remaining 60 ft (18.3 m) of rods and resumed drilling by 0900 h. After drilling a 5 ft (1.5 m) run (Run 106; 735–740 ft; 224.0–225.6 m), the inner core barrel stuck in the outer barrel and required pulling and pumping to free the core barrel. The inner barrel was freed, and core for Run 107 was up by 1100 h (1.4 ft [0.4 m] recovered). Run 107 drilled 8.5 ft (2.6 m; 740–748.5 ft; 225.6–228.1 m), short of the full 10 ft (3.0 m), and recovered 10.5 ft (3.2 m) of core including 2 ft from the previous run. We assigned the upper 2.0 ft (0.6 m; 738–740 ft; 224.9–225.6 m) of Run 107 to the bottom of Run 106. Run 108 drilled 7.5 ft (2.3 m; 748.5–756 ft; 228.1–230.4 m). However, the core barrel was empty when it came up at 1350 h, so the drillers changed to the rock shoe and put the inner core barrel back in to attempt to recover the lost core. After 3.0 ft (0.9 m) of additional drilling (still referred to Run 108), the drillers successfully retrieved the core at 1430 h. In all, Run 108 (748.5–759.0 ft; 228.1–231.3 m) recovered 10.55 ft (3.2 m) from 10.5 ft (3.2 m) drilled. The drillers continued to run a rock shoe to reduce the chance of core loss from the bottom of the core barrel. The final run of the day, Run 109 (759.0–769.5 ft; 231.3–234.5 m), was completed at 1600 h with 10.7 ft (3.3 m) recovered. The drillers pulled up 40 ft (12.2 m) at the end of the day. The day ended at 769.5 ft (234.5 m) depth with 33.15 ft (10.1 m) recovered from 34.5 ft (10.5 m) drilled (96% recovery).
On 28 October, nasty, rainy, and windy conditions prevailed, and the drillers ran the 40 ft (12.2 m) to the bottom of the hole with an inner core barrel. The core barrel came up full as they recut the bottom section. The drillers then ran 10.5 ft (3.2 m) of new core on Run 110 (769.5–780 ft; 234.5–237.7 m), recovering 9.8 ft (3.0 m). The drillers reported that two sections were swelling, 480–510 ft (146.3–155.4 m; lower Shark River Formation) and 730–740 ft (222.5–225.6 m; Vincentown Formation). The next run (111, 780–785 ft; 237.7–239.5 m) encountered very high mud pressures, and the core in the shoe jammed the catcher, causing the run to be terminated after 5 ft (1.5 m). Trouble continued on the next run (112, 785–792 ft; 239.3–241.4 m), recovering 5.5 ft (1.7 m). The drillers reported very high mud pressures (800 psi) while drilling; when running for core, pressure dropped to 200 psi. Continued high drilling pressures, it was feared, would blow the pump, causing us to lose the rods and possibly the hole. The drillers believed the hole was not straight and the rods were shimming around the swelling clays at the base of the Shark River Formation (480–510 ft; 146.3–155.4 m). The drilling team considered three options.
inch (12.4 cm) reaming bit (i.e., must be <5 inches [12.7 cm] to fit inside the casing), requiring 2–4 days.Co-Chief Scientists Sugarman and Miller favored option 3 with the following priorities: (1) save the hole for logging and (2) recover the Cretaceous/Paleogene (K/Pg) boundary. The drillers pulled the rods to 450 ft (137.2 m) and began to ream the hole with the idea of coring Thursday.
On Wednesday 29 October, the drillers successfully reamed the hole from 450 to 792 ft (137.2 to 241.4 m) and ran 8 ft (2.4 m) on Run 113 (792–800 ft; 241.4–243.8 m). The core was described by geologists onsite on 30 October.
Freezing conditions on 30 October delayed the first core until 0915 h. The drillers ran 5 ft (1.5 m) but only caught 1.1 ft (0.3 m) of slightly deformed core that may be from the previous run; the new core slipped out of the barrel. The next 5 ft run (1.5 m) recovered 8.6 ft (2.6 m) of core. We combined these two 5 ft (1.5 m) runs into Run 114 (800–810 ft; 243.8–246.9 m). We decided to keep making 10 ft (3.0 m) runs because the 5 ft (1.5 m) runs tended to slip out. The drillers had difficulty getting the inner barrel to release on Run 115 (810–820 ft; 246.9–249.9 m). Both Runs 115 and 116 (820–830 ft; 249.9–253.0 m) came up with virtually full recovery. Run 117 (830–840 ft; 253.0–256.0) recovered 10.6 ft (3.0 m), and the drillers noted a difference in drilling beginning 7–8 ft (2.1–2.4 m) into the run. Onsite, R. Olsson found Cretaceous planktonic foraminifers at the base of the core. The K/Pg boundary was interpreted to be at a surface in the core at 838.85 ft (255.7 m). We decided to run two more cores to get below the boundary for logging. Run 118 (840–850 ft; 256.0–259.1 m) recovered 7.6 ft (2.3 m) and Run 119 (850–858 ft; 259.1–261.5 m) recovered 10.6 ft (3.2 m), including 2.6 ft (0.8 m) from the previous run that had a thick rind on it. The day ended at 858 ft (261.5 m) depth with 57.5 ft (17.5 m) recovered from 60 ft (18.3 m) drilled (96% recovery).
On the morning of 31 October the mudlines were frozen and the drillers decided to forgo further drilling. Recovery for the hole was 635.2 ft (193.6 m) from 858 ft (261.5 m) drilled (74% recovery). Eighty-five core boxes were moved to the Rutgers Core Repository for further study.
On 31 October, P. McLaughlin (DGS) arrived onsite and obtained a gamma log through the rods to 844.6 ft (257.4 m) using the Rutgers University Department of Geology's Century Geophysical Corporation drawworks and the DGS's Century Geophysical slimline Natural Gamma Tool. The rods were pulled, and two logging runs were made on formation. The first was performed using the DGS's Century Gamma-Electric Multitool (Model 8144A). This logging tool simultaneously records a gamma ray log and a suite of electric logs, including spontaneous potential (SP), short normal resistivity (16N), long normal resistivity (64N), point resistance, and lateral resistivity. The first open-hole run was to 848.8 ft depth. Because the upper 200 ft of the hole is cased, a second run was made using the DGS's Century Gamma-Induction Logging Tool to 845 ft; this tool simultaneously records gamma and magnetic induction conductivity logs in both the open and PVC-cased portions of the hole, and the induction log can be converted into a pseudoresistivity log.
The hole was plugged with concrete on 1 November, and the hole was abandoned.
