February 2013

The last year has been one of waiting: Waiting to be sure that the sink is stable and that none of the construction compromised the geology or the hydrology, waiting to see how the FS felt about our management plan (they seem to approve), waiting to see if the Western Cave Conservancy might want to join the effort (they might), and waiting for me (David) to decide that the political cracks are wide enough for us to just fall through and get the job done. I can’t help but get the feeling that this is expected of me.  I guess, since I said I was doing it.  I still feel there’s some doubt out there that the Mistress dig will get us back into the Cave Next Door.  I think it has already done that and now the work must begin as per the management plan.  Right now, no matter what the future of this project, it is still necessary to fill the sink in around the culvert, and to cap the top of the culvert.  The filing in has been going on for 3-4 years.  The material for back fill is coming from the bottom of the shaft to minimize surface disturbance.  Right now, the most disturbing surface phenomenon is how fast the re-growth in the clear cut is growing, and being a native of Oregon, I’ve seen lots of them growing night and day keeping Oregon green

        But the surface is supposed to change like that and in many other ways for many different reasons, and believe it or not, not all those reasons have to do with man and his manipulations of that which he calls his resources.  For nature, even drastic changes seem to be acceptable and common on the surface.  It adapts fairly quickly.  But-not nearly so common underground.  There, changes are much slower and occur, usually on a much smaller scale.  This would imply to me two things.  One-what goes on underground usually does not have a large impact on what happens on the surface.  It is of course the other way around.  And. Two- we have to be much more careful of what we do underground and how we do it because even our most casual visitation, activities that are invisible and have almost zero impact on the surface, can have very long lasting effects underground.  Our management plan is of course designed to minimize these impacts, and constrain them to the “defined” trail.

        So what has changed below in the dig during the last year?   (You can see the previous blog for other info about this.)  I have made it a priority to check for any changes, which means—“Has anything moved?”  I can find nothing.  Small cracks around fractured slabs of igneous dikes at the opening to Chamber A still hold the same tiny chinks of mud they held when they were uncovered over 3 years ago.  I checked very carefully for any separation that would imply movement in the concrete work with any rock imbedded in the wall.  Many of these were boulders in situ and had never been moved by us, only uncovered.  They were wedged and stable naturally.  I looked for spaces between the concrete wall and the igneous bedrock of the south wall.  There is not the slightest sign of any movement what so ever and this in spite of earth movements that were felt in the Illinois Valley from an earthquake off the California coast by Eureka.  Dripping water has washed everything bright and clean.  The Mistress is looking beautiful.

        The past year did see progress though.  The stonework around the top of the culvert which is part of the locking cap on top, was continued as was the filling in of the sink with its accompanying stonework and drainage.  Meanwhile at the bottom, the last section of concrete work, that firmly cemented, and wedged the bottom-most sink boulder to the south wall was finished sometime last summer.  It was like we constructed the perfect chink rock that held everything in place, although nothing had moved.

        Now geologically, all that construction, right down to the 80’ depth has brought us to what seems to be the neck or pinch point in a sort of hourglass shaped sinkhole.  Below us the rubble is more loose and hollow.  There is much less talc-y mud.  The 12’ wide talc seam of the north and east walls, below the collar 20’ above, have compressed down to not much more than a 1 foot seam at 80’, leaving only 3’ or 4’ from the marble west wall to the igneous south wall at the pinch point.  This space seems to be mostly due to the dissolving of the marble by the underground water that caused the sinkhole to happen, and by the washing out of collapsed talc.

        Late in January of this year, Charlie and I snow-shoed into the Mistress after many months of absence.  We removed almost 4’ of wet packed snow from the roof, (It’s the most water I’ve seen stored in the mountains this time of year for some time.), and crawled in and found it as described above and briefly noted earlier.  Last week another 21 buckets were lifted from the bottom to the top with the help of Tony.  Charlie and I are learning how to integrate another body into the system while maintaining absolute safety.  Tony’s cave and work experience, his common sense, and his enthusiasm for the project are a great encouragement and motivating factor to a couple of old men who may not doubt their sanity but have had to measure it on a different scale.  Now remember that everything is vertical and gravity always has the last word if you even give it a chance to speak.  We are moving 150-200 pounds of rock and mud out of the bottom in white plastic buckets strung out and clipped onto a pigtail cable, being lifted  20’ up to and through the collar into a 30” laddered steel culvert, and then 60 more feet to the surface.  Hopefully all you ever hear is the soft scratching of bucket friction and never a peep from gravity who always seems to take its slightest whisper to cataclysmic proportions.  Every wrap on the cable, its speed even at any particular point in the lifting, every twist in the pigtail cable, and the idiosyncrasies of each bucket clip and bail, and how each bucket hangs from each clip, the threading of the buckets through the safety collar, and each imperfection in the culvert: each and all must be within very small parameters for 5 buckets, less than ½ full, to make it all the way up.  So, it’s not really surprising that while lifting those 21 buckets, only three fell back down the shaft.  Kind of scary though, especially for Tony who was digging at the bottom.  Also not surprising, was that all safety structures and procedures worked perfectly, unlike those moody swinging buckets.  Now we were hampered by difficult communications due to old ears, and something about radios.

        As we continue to move through the second largest void we have encountered-Chamber A being the largest- more air is showing up behind the igneous south wall.  At first I noticed where some rubble had fallen from a 4” crack about 2’ above the dig floor, and exposed a narrow void extending up and behind the south wall.  By the end of the work day, Tony reported that further down the wall you could look up into more void that seemed to be connected to the first.  I think his is what I expected as I believe the main cave void to be behind the south wall, much like Chamber A was behind the west wall.  I think this because of the airflow and water drainage through the joint fractures (1”-2” wide) in the marble at the adit level 30’ above.  We have to dig down and find a way under and through the south wall.

        Now since it is my job to worry about everything that might possible go wrong, I’m going to worry about igneous ceiling.  I continue to believe that the sinkhole exists because faulting has broken some of the igneous dikes and these broken dike pieces have fallen into the void as the marble dissolved allowing the sink to collapse on up to the surface.  I know I have said all this before, but it is important for me to constantly review my theories and compare them with what we actually find.  We do find loose pieces of igneous on the south wall-ceiling.  All these must be removed of course, while they are still at floor level. As we descend we can leave nothing loose above our heads.  They tend to be think plates and they come form some different type of igneous that appeared at 80’ where the hard blue solid wall we had been following down, angled into this softer, browner variety.  Perhaps a meta-basalt as opposed to a plutonic dike.  I don’t know, but I do know I prefer a nice solid marble ceiling/wall to this igneous stuff.  We are going to have to be careful, especially with it being riddled with voids.

        At this point everything is too drippy to do any concrete work so shoring is being done with timbers.