Fall 2003 Update
October was a good month for cave digging. Working alone most of the time, I managed to get another 100 hours of work done. It takes 20 minutes to get 3 buckets of dirt out of the hole, 9 buckets an hour with easy digging, usually less. It takes about 30-40 buckets to remove enough dirt to build another set. It takes about 3 hours for me to cut the beams for the set and another couple hours to place the beams and backfill. I’m working evenings and weekends on this. I dig into the unknown.
The only way I have of “knowing” what’s around me is by probing with a re-bar. The dirt is still loose and soft. You can probe 6 feet into soft clay, forward and down, pushing the rod by hand into the soft clay. The material is loose with many small open water drainage channels that are more pronounced around the boulders. I have dug a tunnel from the bottom of the shaft about 5 feet in a southerly direction and the material is getting looser. Under the tunnel I have dug down through the soft clay to boulders, very leached serpentine. This has been filled with loose rock to facilitate drainage. So far we haven’t had enough rain to bring the water up enough to show in the shaft.
On a weekend late in October, the final telephone connections were made. We got a dial tone and made our first phone call. The Cave Next Door is connected to the world thanks to many hours of hard work by many volunteers. The phone number is 541.592.3155.
December
I made a trip to the Mistress shaft on Dec.11, my birthday. I met JD there. We checked the dig and probed it thoroughly. About a foot back from the face at the top of the wall a basketball-sized rock had fallen out. Removing dirt from this area exposed rough serpentine rock all across the top of the face. Probe holes were driven down and across the face. The lower down the face, the deeper we were able to probe. I don’t know if the rock is a big boulder or bedrock, but it seems to be the source of the rough serpentine boulders I’ve been taking out of the clay. I could also be the obstacle that caused the sinkhole to move sideways. As the sinkhole formed from inside, it would have had to move around this overhang, be it rock or bedrock, as it collapsed up to the surface. This would explain the soft sinkhole deposits on the south side of the shaft into which I dug the tunnel. It was not possible for us to determine if the rock was steeply dipping to the north-east. This would have indicated it was bedrock and could possibly be the hanging wall of a steeply dipping cave entrance, into which the sinkhole collapsed.
Now in my digging I am guided by a couple general principles. One is: to get into the cave by digging horizontally would mean that I am already inside the mouth of the cave, somehow. Say, inside the talus slope that was formed when the sinkhole collapsed. I don’t think that the sinkhole could stay open for very long if the collapsed material had to move sideways into the cave. Gravity doesn’t work sideways.
^^^^^^^^^^^^^^
l l sink
l l
l l
cave l l
talus l l
======== tunnel
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For some weeks now I have been thinking that the loose clay I was digging in indicated precisely that, but the appearance of this rock or bedrock, the short distance I can probe forward or left, and the long easy probes angling down and forward would seem to indicate that I need to dig down. My second guiding principle: the cave has to be underneath me. Perhaps the situation is more like this: (You’re just going to have to imagine this one. I don’t have any idea how to draw it. Martha) Such a scenario, a steeply dipping entrance, would be similar to the 110 entrance to the Oregon Caves. It would also explain the sound of the falling rock I heard last summer. I heard it roll and tumble a ways before it seemed to fall into a void, thumping on the bottom a couple of seconds later. Now I couldn’t dig the shaft any deeper. I hit boulders. I dug sideways until I found rock (bedrock?) and then I could probe down again. So I think it is time to start digging down again, following the loose sinkhole material.
I talked to Jefferson Public Radio this morning, December 7, to a fellow called Liam Moriarity. We are planning a series of interviews form the dig starting early next year and continuing until whenever.
February 2004
Here it is, February and I haven’t started the dig yet. The hole has been active though. Material seems to be working down between the shaft and sinkhole wall, with dirt coming into the tunnel below. As far as I can tell, the only thing that is moving is the loose sinkhole dirt in the “Bell bottom” section with the dirt washing out into the tunnel and rocks staying above. Two days ago, I spent a ½ day working in the shaft. I filled the hole that had appeared alongside the shaft, with Port Orford shoring. It took about 10 posts to fill the hole in. I did some banging and shoving hoping to hear something break loose, nothing. But the hole from above sure looked a lot bigger than the pile of dirt that came out in the tunnel. If such was the case, then some of the subsidence could have been going into the cave. I heard nothing to indicate that such was the case. I believe the main reason for this dirt moving is that the rock at the end of the shaft is bedrock, which is where the ground water is moving and washing the soft dirt out of the sinkhole deposits allowing the rocks to settle, creating the hole I had to fill. The shaft is wet. The sump under the floor seems to be working as the floor is dry. I have made three or four trips into the Mistress packing in an electrical system. A small hydro-turbine, battery, wires, lights, plumbing, etc.
March 2004
It has been interesting watching the ground water rise. You could see it changing by watching the back wall get wet and wetter as December became January. The early rains seemed to be heavier in the valley than in the mountains, so it was the middle of December before the back wall showed water. The water didn’t start running down the wall in the normal wet season pattern until a good snow pack developed and then soaked up rain in the latter part of January. Now the bottom 7 feet of the shaft’s N and E walls are running water. The water is sinking into the sump that was built under the tunnel, and then I suppose into the cave below. I suppose that this water is coming off of bedrock and may be the major reason this sinkhole developed. How long has this cave been buried? Was this entrance (if it proves to be such) buried at the same time as the original entrance, a ½ mile away? Or, has this entrance formed by centuries of this water falling into an underground void, slowly dissolving the marble ceilings until it reached the soils, which eventually collapsed, by the action of groundwater, into the dissolved chasm below? Is that postulated chasm directly beneath the tunnel, and if so, what is between the two? Rocks? Silt? A bedrock ledge, hopefully. The sump was dry down to boulders that seemed large and secure. It is possible that a stream used to flow into the cave here, and these boulders are its bed? The only way to answer these questions is to do some more digging.
July 30, 2004
An update is in order. We have had two meetings with the Forest Service. I have turned into them a cave management-research plan, a project proposal, and project guidelines. On May 5, we met at the dig and they didn’t seem overly concerned about any surface disturbance (insignificant) but were not too convinced that there was a cave down there, especially one connected to the original dig ¼ mile North. They recommended a dye trace and more probing before the project begins.
John D has designed the dye trace, but a fluorimeter is still unavailable and I don’t want to do the dye trace before one is, so that samples can be processed. So I am probing. Don Young has made a security gate and a clay auger for probing. I have been using the auger to probe the face of the tunnel.
Dan S has helped me remove the dirt from the tunnel that collected during the winter. I thought that most of the dirt had come from the subsidence mentioned earlier, that occurred between the south wall of the shaft and the side of the sinkhole. After removing the dirt, it was obvious that most of the dirt in the tunnel had fallen from the face of the tunnel and very little of it had come from the subsidence. Probing at the face of the tunnel revealed only bedrock (altered diorite), clays that seemed to be more associated with hydrothermal alteration of the bedrock than with sinkhole deposition, and a dark gray gabbro (?). I needed to take a better look at the area that had subsided.
On Wednesday, July 28, I decided to remove the logs and rocks I had put into the subsided hole and take a better look. As I was removing the beams I could hear the stuff below settling even deeper. The soil’s clay had dried since winter and was more stable. I was able to remove most of the wood, but some fell deeper, out of reach. It was plain to see that the hole was at least twice as big as the tunnel and the small amount of dirt in the tunnel was not enough to account for al the material that had subsided, and disappeared. There were no rocks in the hole, just gravel and the logs I couldn’t reach some 7-8 feet down. There was a dark hole in the southwest corner that seemed to be where all the material disappeared into. Was this the way into the cave? I won’t know until I do some more shoring and can take a look, safely. I have a lot to do. Cameras, Forest Service, measuring instruments, cavers, internet, public radio, and so forth.
End of August 2004
I have removed all material –dirt, logs, and boulders, from the south wall of the sinkhole. This meant taking out all the loose sinkhole material that had filled the space between the shaft and sinkhole. I was able to do this from inside the shaft, for obvious safety reasons. I followed that dark hole that logs seemed to be disappearing into down another 4-5 feet, down to below the top of my tunnel. This was done with help from Dan S and a whole Saturday with Don Young. When Don and I finished that day, I could see a soil profile exposed from a smoother hard face of bedrock (striking more or less east and west, the same that my tunnel came up against) at the bottom, then some weathered or altered bedrock grading into soil-like clays. On top of all this, was the cobble-dirt-clay soils 18 feet up to the surface. With the whole southern wall of the sinkhole exposed down to the top of my tunnel it was obvious there was no way into the cave. I dug the dirt off the side of the sinkhole then, caving it into the deepest part in the SW corner and then probing the sides to make sure I wasn’t missing an entrance that got re-plugged with just dirt. I dug into holes I had augered up from the end of the tunnel. Nothing. But I was still following the loose sinkhole deposits down. I t was easy to tell the difference between dark sinkhole deposits with more organics and the reddish-yellow clays and dirt of the altered bedrock. I f there was material from the subsidence going somewhere else than into my tunnel then it had to be outside my shaft on the west side of the tunnel.
Now I had a big hole down most of the sinkhole south wall, with a fairly large boulder suspended in the middle by Pumba prayers, I believe. Thank you, Pumba. I figured this might be a problem when it rained so I needed to backfill it. First, Dan S. helped me take the dirt out that I had caved off the walls looking and probing for cave. I didn’t want it just washing into my tunnel like it did last winter. I started filling it with cedar logs and rocks, placing everything carefully from the bottom up, supporting the sides of the sinkhole. Ernie Coffman and his friend Dick helped me finish this off one Saturday near the end of August. You can sure move material faster with 3 men than with one. The next Tuesday, J.D. showed up from Eugene and Brian from the Ore. Caves. With their help we were able to tear out the west wall, and make and drive enough splilings into the west wall to start removing dirt to dig another tunnel beside the first one. I started removing dirt the next Saturday. I’m planning on building a tunnel without a shored bottom, so I can sink a shaft through the bottom, if necessary.
End of September 2004
With the west wall removed at the 30’ depth, a hole was gouged out with the ceiling and walls all of soft bedrock, and the floor of sinkhole detritus. Loren helped a couple of nights in the removal of this material. I then re-shored the old tunnel, moving vertical shoring over and cutting off some of the flooring beams in the shaft and old tunnel to construct a 4’ x 4’ shaft slightly to the west of the old one starting at the 30’ level. I then shored up the ceiling and walls and prepared to keep digging down. Before digging, I probed with a 10’ rebar. I was able to push the rebar all the way down by hand through soft gravel with rocks in it. I one place, straight down, I probed 12’ below the bottom of the shaft. I now have this new shaft, at the bottom of the original one, shored down 2’ and dug down anouther6’. There is still much material to remove in order to shore the sides. I can still probe another 4’-6’ below the bottom of the hole. There is no indication of an opening into the cave. The south and west wall are rotten bedrock. The east and north sides of the shaft are loose sinkhole material. Have I missed an opening on the east or north sides where the water is coming from? Am I actually digging down into a rubble pile inside the cave? I filled the 6’ deep sump at the bottom of the shaft with water, probing the walls at the same time. The water just slowly seeped out with no indication of wanting to go out in any particular direction.
September 30 2004
A couple of digs after writing the above, I had reason to believe that I could find some form of bedrock in all corners of my shaft. This is hard to ascertain as the bedrock is very soft and altered and looks very similar to the clays in the sinkhole.
In an intense day of digging with my son, Nathan, and my grandson, Isaac, we removed two large (500-700lbs.) boulders and sinkhole material. It has become very obvious that I have rotten bedrock on all sides of the shaft with about a 2’ x 2’ diameter sinkhole in the middle. This shaft is shored down 7’ below the bottom of the old shaft, making the total depth (measured) 33’. 26’ plus another 7’. I am preparing to dig down just the sinkhole area, run it full of water, and try again to get it to drain.
November 21 2004
We had a dig a couple weeks ago and I dug a hole at the bottom of the shaft (33’ level) down another 6’. This was not a full shaft size hole but was dug down until the shovel felt like it was hitting bedrock. I was at the level I could probe down to when I first tore out the west wall. I filled the hole with water. The bottom 6’ sump filled quickly, being smaller in size. In an hour the shaft had filled up to the 28’ level- 2 feet below the bottom of the original shaft, and stabilized at that level.
I did some probing with the re-bar into the sides and bottom of the 6’ sump without any apparent affect on how fast the water was draining. The only soft probe was in the NE corner probing sideways. I left the water turned on for 24 hours. The water remained at around the 28’ level. The water was turned off. In one hour the level dropped 4’- approximately 64 cubic feet . The next hour, it dropped another foot- 16 cubic feet. The water was turned on and left running in the hole for a week, keeping at the 28’ level. The water was turned off, and a few days later the hole was dry. I had put some floaters on the water to see if there was any preferential direction to their floating, but I could discern none. The water had washed the rocks in the hole well enough that I could easily discern bedrock on the south and west, but the north and east sides still showed fill with varied rock types. Looks like I’m going to have to take a closer look at the north and east walls.
January 1, 2005
It has been 5 years since Don, Jenny and myself were in the silt room measuring air-flow on a cold, snowy January night. I sometimes feel that I haven’t done anything right yet to get back into the CND. I have a hole over 40’ deep that I can barely get water to drain out of, much less find a cave underneath. I constantly review the facts and challenge others to disagree with me to see new perspectives and then decide what to do. What can you do in the bottom of a 40’ hole with shoring all around? Where to go? What to do? When all efforts seem to go nowhere?
Larry Tigue from up in Washington got hold of me last month and wanted to help dig. He had done some cave digging in the past, more then me, and I was desperate for any new perspective, or perhaps the cave’s time had come. It seems to be at this point in these projects that superstition takes over. Larry’s only vacation time was the last week of the year and the weather could be tricky. But he, JD, and I put a couple of days in before the New Year and at this point I can’t say whether progress was made or not.
When I left the dig before Christmas, the hole had water in it at maybe the 35’ – 36’ level, a little lower than I was able to get it previously. The water was entirely due to ground water from some rainstorms the second week of December. When JD, Larry and I got to the dig, after Christmas, there was a puddle of mud in the lower sump where deposits had washed out of the NE corner. The rest (bedrock covered with mud) was unchanged. I wanted to probe E and N so I removed the floor of the original shaft and took enough boulders and mud out to be able to probe. Probing east into the wall always came up against the rotten bedrock sinkhole wall. The more down I went, the deeper I could probe, and one or two probes even went down to the lowest level I can probe in the sump. It seems to me that if I am 10’ down into bedrock and the only way out of the sinkhole is through the bottom, so to speak, than all probes sideways should be into some kind of bedrock. If I could probe sideways, it might indicate a way into the cave. So far all sideways probing has come up against bedrock, (or whatever deposit or formation is represented by what the sinkhole penetrates below the cobbled surface alluvium.) The only direction sideways that is still unknown in my head is a northerly direction back towards the creek. Perhaps there is some kind of opening underneath a hard layer of bedrock that is responsible for the high water table to the North.
After some probing on the second day, we decided to put some water into the hole. Larry was in the bottom when we turned the water on. We started slowly. Now a surprising thing happened. Larry said, “It formed a whirlpool and I saw some woodchips sucked down!” I looked over into the sump and saw the whirlpool at the bottom with woodchips whirling around and starting to make a suction noise. Larry and I decided to exit in case what we were seeing was a precursor to some more significant event, i.e., sinkhole collapse. The suction seemed to continue as we climbed out. JD went down to see for himself. While probing the whirlpool in an attempt to open it up more, it seemed to stop. Then started again, then stopped. Any further probing failed to start the suction again.
Had some drain opened up over Christmas and as soon as we put water in, it was active until our probing plugged it up? Had the water run into some passage or hole and when that was full the suction stopped? Don’t know of course, but we turned the water off, closed up, and left the dig. The next day came with heavy snow in the mountains, and more storms coming I would like to take a few buckets of dirt from the west wall, down where the whirlpool formed incase that would unplug something, then put water back in the hole and let it work naturally. Nothing more happened. |
