October 25th Work Weekend at the Backdoor
Workers:
Bernhard Arnold, Roger Brown, Greg Buckley, Bill Copeland, Rick Hines, Andy Isbell
Tasks accomplished:
1) AC wiring completed
2) Last of the bolts in but not tighten (need impact wrench)
3) Entrance hatch counter balanced
4) Water flow in shaft measured
4) Some additional clean up
For a change I started down Fright night instead of leaving KC early Saturday morning. I spent the night in Warsaw and that let me pick up Greg Buckley in Wheatland at about 7:00 Saturday morning.
Shortly after last month’s electrical work I started purchasing the hardware we needed to finish the job. I even modified some hardware for our use. I thought I had everything we needed. Wrong. By 9:00 AM Saturday I was searching Camdenton for a half-inch drill bit, a chuck key and wire nuts. Switches, outlets, breaker, fluorescent lights and a main ground wire were installed. Early Sunday the last of the electrical work was finished.
We did notice a problem with extreme condensation on the inside of the silo. With the outside temperature at or bellow 50 F the cave was breathing out when we had the hatch open to work on the electrical below. The cold metal walls were soon dripping with condensation. In the future when the outside temperature is below cave temperature the hatch should be kept closed as much as possible and the exhaust fan used to vent the humidity. We should also plan on painting the inside with a zinc based primer and a coat or two of paint to help prevent rust.
After a beautiful prior week the weather turned cold and wet for our Saturday activity. It was mid afternoon Saturday before the rain stopped. We worked mainly inside on the electrical job Saturday but it was necessary to work outside in the rain to place some of the bolts in the silo.
A special thanks to Roger Brown who drove down the prior weekend and did some clean up on his own and then returned this weekend to help.
With Roger’s help we were able to place the last of the stubborn bolts in the lip between the two silo sections. On the most stubborn ones we had to drill out the half-inch holes to get a bolt in. We also got the last of the bolts in the open holes in the side panels that originally secured a large funnel in the base of the silo. Fifteen or 20 long bolts were placed in some of the holes to provide points to hang rope and stuff on the silo walls. We drilled holes in the concrete pad and set stainless steel anchor bolts to secure the silo to the pad.
We jury-rigged a counter balance on the entrance hatch. A steel cable was connected to the hatch and threaded through a pulley located near the roof. All we needed was a counter weight. We looked around for a piece of steel or a rock. The first rock we picked up had a natural hole and turned out to be just the right weight!
On Sunday morning Andy Isbell and I suited up for a trip down the shaft. I had two goals. First I attached about 20 wire ties to secure the rope light to the ladder so that the rope light connectors were not supporting the entire weight of the light.
The main goal of the trip down the shaft was to measure the flow rate of the water entering the shaft and flowing into the cave. First, on the way down the shaft I noted the shaft was wet from the culvert down. During the dry months of summer the top 20 feet of the shaft is nearly dry. At 43’ below the surface a small stream of water entered, the only concentrated flow I noticed all the way down. At the bottom, the ladder complicated catching all the water coming down the shaft at one time. Andy and I held a plastic tarp so that it caught water from the half of the area of the shaft in front of the ladder. The tarp funneled the flow into a 5 gallon bucket. In three minutes we collected about 2 gallons. We then positioned a second bucket on the far side of the ladder and threaded the tarp through the ladder and into a second bucket. The flow on the ladder half was obviously less than the other half and after 3 minutes we collected about a gallon. The two buckets were combined and equaled 3 gallons to yield a flow rate of 1 gallon per minute. We will repeat the measurement periodically to see how the flow changes with season.
After a little clean up outside the silo we packed up and headed home.
Next month we will try again to finish tightening down the bolts which means we will need someone with an air compressor. We also need someone with a truck to haul scrap metal to the local dump. Please let me know if you can help the weekend of November 22.
Rick 913 897 4258