The creation of Big Bucks Pit, a shaft entrance to Barberry Cave
Nevin W. Davis
Well, it's done. We have yet a third entrance to Barberry Cave. In a period of less than 41 months, three entrances to an entranceless cave have been dug. This must be some sort of record! Especially considering that the length of the survey is only 2.72 miles. I need to go back to 28 May 1993 to explain the chain of events which lead to the opening of Big Bucks Pit.
It was on this date that the saga of Barberry Cave began. Mike Nicholson, Gregg Clemmer and I set out to clear the trash and barberry bushes which clogged a little crack in the bottom of a sink on a neighbor's farm 4000 feet south of my house (Clemmer 1993). On this Memorial Day weekend perhaps 70 man hours of effort were expended to reveal the entrance to a cave which over the next 9 months grew to 0.96 miles of survey. It was obvious to those involved that the cave held great potential. After all one side passage was only 1400 feet from Butler Cave and the air blowing over the Near Sump at the downstream end of the survey would entice even the most confirmed skeptic. There was only one problem. Access to the cave was through the Hemlock Highway. This crawlway required 75 to 90 minutes to pass and at the end the explorer was only 420 feet from where he started! That could be up to 3 exhausting hours stolen from a cave trip. Something needed to be done to facilitate the exploration of the cave.
As luck would have it there was a sink filled with field stone about 100 yards from the entrance. It was over some side passages at the far end of the Hemlock Highway not far from Feeder Meeter Pit. A cave radio location on Pancake Weekend 1994 (Rosenfeld 1994) confirmed the location and depth and a second dig was started. For five weekends from 19 March 94 till 5 June 94 stones were tossed and a 12 foot long tank with its ends cut out was installed to stabilize the excavation. At this point known passage had not been intersected. On 7 June 94 after making a careful drawing of the excavation and the cave survey, I was able to take my trusty digging bar and plunge it through the wall of the dig at the bottom of the tank into surveyed cave. By 28 June a 2 foot diameter lateral culvert had been installed into known cave and the whole area was backfilled and graded. About 365 man hours were involved in the whole project and it did provide excellent access to the cave. Between 25 June and 4 Dec 1994 the cave grew from 0.96 miles to 1.94 miles (Schwartz 1994, 1999). The Tank Entrance was certainly proving its worth.
Pleasant sunny days are often followed by dark rainy days and so it was with our little cave project.
The Barberry Rescue
The following is the first paragraph from the Prologue of Jeff Uhl's article "But I Don't Want a Rescue" (Uhl 1994).
"On Friday 13 January five people (Nevin W. Davis, Tommy Shifflett, Mike Artz, Mike Ficco, and Ben Schwartz) entered Barberry Cave. They intended to camp beyond the Near-Sump, explore and survey for several days, and exit the cave at 13:00 on Monday 16 January. On Saturday 14 January there was a very heavy rain storm on the area. This unexpected event flooded the Near-Sump and stranded the five cavers inside."
What followed was the biggest excitement to occur in the area in the last 100 years. The Rescue Squad and all their buddies in surrounding counties along with major news media converged on Barberry Cave. The resulting media event was something cavers can do without.
We were ambushed in our own cave project! As a result of the publicity and efforts of well meaning would-be-rescuers we were locked out of the cave. My neighbor, the land owner, has not spoken to me in person or even made eye contact since the "Event." Clearly if we were going to continue exploration of this beautiful and strategically located cave we needed another plan. Read that ---another entrance!
The project begins
Most of the large passage in the cave underlies my property, Springhouse Farm. At one location the ceiling above a 45 foot high pile of breakdown is only 70 feet from the surface. So choosing this location for our third entrance, on 11 November 95 I signed a contract with W. F. Caldwell Well Drilling to sink a 10 inch diameter bore hole into the cave.
Bill Caldwell's air rotary rig was set up on the "spot" the morning of 8 December 95. It took some time to clear the snow from the equipment and get the Detroit Diesel engines running. At about 2 in the afternoon Phil Lucas and I were counting down the feet until the drill would break through. I said, "He's got about 6 inches to go".
The drill inched downward. Then with a small lurch and a change in the sound he was through. The hole was then reamed to 10 inches. Because of an impending snow storm, Caldwell packed up his equipment and was on the road in 10 minutes. Phil and I lingered long enough to lower Marks Products GeoVision Jr., a well video camera, down the hole to confirm our location in the cave. It was "bingo" right on the mark. In the process we noticed that you could hear the sound from the 3 foot high waterfall in the cave just downstream from the well.
On 27 December 1995 Gregg Clemmer brought his family out to Springhouse Farm for a look at the bore hole. This time when we lowered GeoVision Jr. it was attached to a working VCR and we videoed the well and the 50 foot high cave at the bottom.
Since we planned to sink a shaft following the well, Caldwell had not cased it through the soil zone. His well log showed a depth to bedrock of 13 feet so Ben Schwartz secured a piece of casing from his father that was 14 feet long and we lowered it into the well. In the middle of January after a thaw and storm I noticed that water was standing only a foot below the surface. Our well had collapsed! A review of the well video revealed that contrary to the driller's log, bedrock was actually more like 26 feet below the surface. Another emotional roller coaster ride was in progress. The well is drilled (the high) the well collapses (the low point). This wasn't to be our last disaster!
The information that bedrock was 26 feet down was both good and bad. It meant that there were 13 less feet of rock to sink a shaft through but it also meant that we would have to shore 26 feet of earth before bedrock was reached. While pondering various options I talked to Paul Cunningham. He suggested that we hire his track hoe to dig a hole and install a 4000 gallon (24 feet long x 65 inches in diameter) tank which had been laying around his farm for 20 years. The ends could be partly cut out and the tank would span 24 of the 26 feet through the soil zone.
On 20 March we had the tank, we had the track hoe, we had David Armstrong to operate it but I had to teach so Ben Schwartz took over the supervisory role.
At 1:00 PM I got a frantic call at work that there were rock ledges in the way and I should come home. It seems that the well hole in traversing the soil zone had gone parallel to a subsoil cliff piercing a ledge at 13 feet and continuing on downward to bedrock at 26 feet. We needed to remove some of the ledges and move the bottom of the cliff back a few feet to center the tank on the well. You ask, "How did we know where the well was located, after all it had collapsed?" I had rigged a wire high above the well from which a plumb bob could be suspended. Thus the well could be relocated anytime we wished.
With the help of an air compressor and rock drill we made short work of the offending ledges and by the end of the day the tank was set and nearly plumb and probably centered on the well. Two days later the excavation was completely back filled. Our problem now was 6 feet of water in the tank.
Draining the tank
On 23 March the water had mostly gone away so Ben Schwartz and Mike Ficco entered the liquid mud world at the tank bottom and eventually uncovered our precious well. The rest of the weekend was spent starting the shaft which would follow the well into Barberry Cave. With three weekends work we were 6 feet below the tank. If you'll remember it was 26 feet to bedrock and our tank was 24 feet long. We had a 2 foot seam of mud on the tank - bedrock interface. The tank was supported on bedrock at only one point on its circumference. This problem needed to be cured.
Most of the weekend of 20 April was spent cutting rebar and welding it in place between the tank and pins driven into holes drilled into bedrock. Plywood shoring was placed behind this grid. We knew that this was only a temporary solution to the mud problem but we were eager to advance the shaft downward.
By 10 May 1996 our shaft had advanced to 18 feet below the tank. All the rubble from the excavation was dumped down the well. Pieces too large for the well were broken smaller. Also I should mention that at times during the previous 5 weeks as much as 5 gal/min of water entered the shaft from a soil pipe on the southwest side of the excavation just under the tank. The water made for damp working conditions but in the end just cascaded down the well.
On 15 May we had 2 inches of rain. I descended the shaft observing perhaps 60 gal/min of water entering. The sound of the resulting waterfall was audible for at least 200 feet away. On 16 May we had 1.5 inches more rain and my visit this time was greeted with silence. The tank had filled to within 12 feet of the top with water!
Obviously the well was blocked. I managed to pull up a 50 foot cable ladder which was hanging in the shaft. It was severely stuck but I managed to remove it with large clods of mud sticking to the bottom. The subsoil around the tank had liquified. Our temporary shoring could not take the force and suffered a collapse. There was no option of removing the plug at the well because if we did, draining the water would remove the buoyancy and all of the waterlogged mud behind the shoring would cascade into the excavation.
Any options were soon removed as the tank sank a foot and large cracks began to open at the edges of the track hoe excavation. This was all accompanied by a strange splashing sound coming through the walls of the tank. An emergency call to Phil Lucas at Water Sinks produced all manner of ropes, come-alongs, and slings to secure the tank from falling into the widening collapse. Soon after the tank was secured the surface on the west side of the tank gave way to a roiling caldron of liquid mud. The 18 foot excavation below the tank was certainly filled with liquid mud. I was depressed!
By 25 May the water had drained from the tank to reveal a large dent in the bottom and the fact that our tank was now an ellipse with a major axis of 70 in and a minor axis of 60 in. By this time I had also used my tractor front loader to back fill the collapse on the outside of the tank. We were back to where we were on 22 March except now the well was covered with 18 feet of muck not 18 inches.
If we were going to continue this madness, we needed to remove the mud. To remove the mud, the water problem had to be solved. Without a drain, anytime it rained the shaft would fill with water. On 25 May Ben, Gregg, and I used compressed air and water to jet a one inch diameter steel pipe through the mud to the well collar. We even managed to blow air down the well.
With this encourgement Ben and I constructed a 8 inch diameter, 700 lb pipe which we hoped could be jetted through the mud to the well. By 23 June with the expenditure of 110 man hours the pipe was sitting on rocks 6 inches from the bottom of the shaft and not quite over the well. Water would not drain from the 8 inch pipe into the well so this effort was a failure. Back to the drawing board. We had invested so much time and money at this point that project failure was not an option.
Water was a problem we could deal with by pumping and bailing as long as there were no severe storms. The mud had to be permanently walled off. A new plan evolved.
The culvert solution
We would dig out the mud bucket by bucket 8 feet below the tank. At this point we were 7 feet into bedrock. We would repair the temporary shoring between the tank and bedrock, wash the limestone walls, lower a 11 foot long 42 inch diameter culvert through the tank to the top of the mud, and fill the space on the outside of the culvert to the tank and the limestone walls with concrete. This all had to be done quickly with all supplies at the site before excavation could begin. By 4 July we were ready. Between 4 and 9 July the 8 feet of mud was removed, the shoring was repaired, and the walls were sprayed clean. Of course any water which entered naturally or otherwise had to be pumped or bailed out.
10 July saw Jean Hartman, John Rosenfeld, John Sweet, Ben Schwartz and I installing the 42 inch diameter culvert through the tank. The bottom of the culvert was supported by a wooden platform laying on the mud floor. The tank and culvert overlapped by 3 feet and this space would be filled with concrete locking the two together. The top of the culvert was covered by a tight fitting lid which would prevent the concrete thrown down the middle of the tank from entering the culvert diverting it instead to the space between the limestone walls and the culvert. The remainder of the day we mixed one cubic yard of concrete with a small mixer and dumped it into our excavation. This tested our forms, our theory, and it served to lock the bottom of the culvert in place for the big pour the next day. Between 8:40 and 10:30 AM the next morning, John Sweet, Ben Schwartz and I mostly watched as 6 cubic yards of concrete were poured around the outside of the culvert and into the annular space between the tank and the culvert. When we were finished the concrete was 11 feet deep. Surely this would wall off the mud.
The next ten days were spent with little things like removing the lid from the culvert and cleaning up. Mike Futrell did his bit by sawing through the platform upon which the culvert rested and removing at least the central part to give us access to the mud below. We had probably walled the mud back but the water was a persistent problem.
Every time we did something on the bottom, the first order of business was to bail water. The fact that the well was sealed caused another problem. The air on the bottom became foul after a short time digging. We had to rig a blower to replace the air every few hours. A moveable bulkhead was installed above the diggers head to provide protection should something fall.
On four different long days, 27-28 July and 4-8 August, 8 people took turns filling, lifting, and dumping 5 gallon mud buckets. At 6:30 PM on 8 August I had the pleasure of removing the last rocks blocking the top of the well. I was greeted with a breath of fresh cave air. For the first time in 84 days our well was open. There was still about 1/2 cubic yard of mud clinging to the walls however.
10 August saw me back at the dig. The first order of business was to remove the remaining mud and toss it down the well. Then I removed the bulkhead and as my final act, washed the entire tank, culvert and 10 feet of limestone shaft with high pressure water until no traces of mud remained. We were now back to where we were on 16 May before mother nature intervened, except that now the subsoil was walled back with steel and 7 cubic yards of concrete. Ingenuity had prevailed on this battle but there remained 28 feet of rock to tunnel through.
The breakthrough
Between 15 August and 18 October a total of 12 people helped with the tunneling operation. We maintained a square shaft about 40 x 40 inches with the well almost centered in the shaft. After 224 man hours on 20 different days we had about 8 feet of well remaining. As luck would have it I was alone on 18 October as I worked with a pneumatic hammer at the bottom of the shaft. One wall was particularly soft and before long I had mined a 4 x 4 foot hole in the shaft wall into a 4 foot wide ceiling crack in the cave. I could sit on a foot wide ledge and peer into the blackness toward the floor 60 feet below. We had achieved our goal.
I decided to have some fun since I knew Ben planned to help the next day. I called him and asked, "You definitely are going to help me tomorrow?" "Yes," He replied. "Don't bother, let's go caving instead," I said. We did do some work on the shaft on 19 October. Ben used the high pressure water to wash the rock dust and loose rocks from the shaft walls. We then set two 3/8 inch bolts and rigged a rope. What a spectacular rappel out of the ceiling past a 40 foot high flowstone cascade. We spent the rest of the day touring what was formerly a very remote area of the Burnsville karst.
The tank now has a locked lid on it and liability releases must be signed to enter. By the end of summer 1997 I intend to reinforce the tank and install electric power to the entrance. I may even construct a small building over it.
Left: Nevin rappels through the 4000 gallon tank which lines the first
part of the shaft.
Right: Looking up the final rappel. After descending through the tank, a
section of culvert, then a bedrock shaft, Nevin has climbed down a short steel ladder to
the second rig point (R in the photo above). The natural fissure in the
cave ceiling provided a shortcut, so that the drill hole (D above) did
not have to be fully excavated. (Photos by John Ganter)
Statistics of the Big Bucks Dig
- 1235 person hours were involved from 11 March til 19 October 1996.
- Work continued on 72 different days.
- There were a total of 31 people involved excluding contract labor.
- Over 57% of the person hours were contributed by two people: The author and cave owner 453 hours and Ben Schwartz with 252 hours.
- The total cost to date: $4097.
- Total monetary contributions to the project: $3465.
It's difficult to understand how so much effort could be expended on one cave and this report doesn't even go into the exploration effort.
To put this into prospective consider that over 1670 person hours have gone into the three entrances not considering the special cave trips, the contract labor, and the planning time, to yield 2.72 miles of survey. I think that works out to 8.6 feet for each person hour of digging. That's a pretty poor average. Not only did the person hours escalate for each successive entrance but the costs also escalated. They went from maybe $30 for the first to about $100 for the second and a whopping $4097 for Big Bucks.
I think the reason for the tenacity was that mother nature just kept throwing challenges at us and we weren't going to give up!
I'd like to close this report with a special thanks to the people who made Big Bucks possible. Without the money and labor contributed by those listed below Big Bucks just would not have been born.
List of persons involved in the project
In order of their contributions
1. N. W. Davis 17. Tommy Shifflett 2. Ben Schwartz 18. Keith Wheeland 3. Fred Wefer 19. Ed Kehs 4. Jean Hartman 20. Mike Nicholson 5. Judy Davis 21. Jeff Uhl 6. Phil Lucas 22. Al Grimm 7. Gregg Clemmer 23. Ron Simmons 8. Mike Ficco 24. Mike Futrell 9. Frank Marks 25. Andrea Futrell 10. John Rosenfeld 26. Jack Igoe 11. Les Good 27. Myron Cook 12. Berta Kirchman 28. John Wilson 13. Jay Longenderfer 29. Keith Christenson 14. Cori Schwartz 30. Scott Jones 15. John Sweet 31. Rocky Ward 16. N. C. Davis
References
Butler Cave Conservation Society (BCCS)
Clemmer, G. (1993). Yet Another "B" Cave: The Ongoing Saga of Masochists in the Cove. BCCS Newsletter 19: 3
Rosenfeld, J. (1994-95). Burnsville Cove Pancake Weekend. BCCS Newsletter 20: 17
Schwartz, B. (1994-95). From the Pool Room to the Other Side - New Discoveries in Barberry Cave. BCCS Newsletter 20: 49
Schwartz, B. (1999). Exploring Barberry Cave. NSS News, Sept. 1999.
Uhl, J. (1994-95). But I don't Want a Rescue! BCCS Newsletter 20: 36
First published in the BCCS Newsletter
