So thats what the whole thing looks like

[+27E_20]

Home on R&R leave, so before I have to go back to Hell for another 6 months, I decided I must go out and find all that I can. Well, I dont know if I found ALL that I could, but after escaping curious county sherrifs and death by train a couple times, this was certainly interesting.

 

 

GC1683

 

I've always wondered what the whole process involved, and now I know- thats a pretty deep hole to dig. I wonder though, if they dug up the RM when they paved the parking lot, what did they do with the station mark? According to my GPS, it was under the parking lot. Did they just pave right over it? And what if theres an underground mark- that has to be twice as deep?! Anyway, Ill be back in the hunt next summer. good luck all!

Edited December 5, 2007 by 27E_20

[+shorbird]

It's amazing sometimes how much digging is done around a concrete post.

 

 

MB0789

[+Black Dog Trackers]

27E_20 -

 

Good luck in Hell and hurry back to the hunt!

Interesting RM monument there.

I wonder it its arrow is still pointing to where Molly is/was. Odd that neither datasheet; MOLLY or MOLLY RM2 has any bearing or distance between them in their original datasheets. MOLLY RM2 is a second order vertically adjusted mark but is obvously way above ground. Perhaps it was dug out and set up by non-surveyors.

 

I can't forget HH0882, found by Jeonlyep:

[CoyoteTrust]

 

This is RM2 for MF1329. This was the first time I ever found any mark in this condition, and I also was surprised about how much concrete was used. This one probably got uprooted due to construction of the newest tollway in Illinois (I-355). Right behind me from where I stood to take a pic, there's a pretty steep drop off of about 15 feet where earth has been moved. I'm not really sure if the RM remains anywhere close to where it originally was -- I didn't measure or anything and the area has definitely changed.

 

EDIT/ADDED: Stay safe over there, 27E 20 - from a fellow brother-in-arms.

Edited December 5, 2007 by CoyoteTrust

[mloser]

I have seen quite a few marks out of their natural element.

 

 

KW1231 RIDGEVIEW was the first tri-station I found in destroyed condition. I was also amazed at how much concrete was in the monument. I borrowed an 8 lb sledge to hammer the disk out of this one (and RM1, which was in the same condition). It took about 10 big hits to basically knock the top off the monument.

 

Last weekend I found the two RMs for 1979 tri-station VETERAN 2 in destroyed condition. Times have changed since 1966 when RIDGEVIEW was placed and now modern methods were used--a 5 gallon bucket was used as a form for the top of the mark.

This is RM3 lying in the woods. The top part of RM4 was nearby (it was just the bucket shaped portion).

 

Finally, there was a time period when vertical marks were precast concrete--from the 30s into the 40s it seems. These were about 4 feet long and set into the ground. Here is the top 2 feet or so of KW1093

 

http://img.geocaching.com/benchmark/lg/251...167cdc58522.jpg

 

These marks were usually set at ground level, and for good reason. They are simply concrete with no reinforcement, so they simply snap when bumped hard, just like this one.

 

And then there is my favorite--WHITE HORSE. The 1882 stone monument had been removed in 1933 and left beside the new monument. I got so flustered when I found the stone that I didn't take a picture of it where it sat, but here is the top. (I broke it in half in preparation for removing it. It sits in my cubicle now and will be at the NGS office when I get a chance).

I had enough sense to take a picture of the bottom chunk.

 

 

edited once to add WHITE HORSE and again to correct a link

Edited December 5, 2007 by mloser

[Bill93]

Some people have commented on how much concrete is in these settings. Although most of them (except the fragile precast ones) seem overly large in diameter, I was surprised that a lot of them weren't deeper than they were.

 

Around here building codes require footings to go to 42" depth to be sure they are below the frost line. That's probably several inches deeper than the frost in most winters. It appears a lot of the elevation marks are nowhere near that deep and so I would expect significant movement. Do any of the people who use these elevations have observations about this?

[DaveD]

None of the images in this thread are for bench marks, that is marks specifically set for height determination. In all the cases here the shorter marks are reference marks for triangulation stations and were never intended to be used as primary bench marks for height determination. While accurate heights may have been determined for them at a later time, when they were originally set they were meant to be references for the primary triangulation station and did not need to be set so deep.

[+Black Dog Trackers]

Well, to this collection, I'll add this mysterious mark that I found eroded out on a small beach on the Potomac River.

[CallawayMT]

Here is a second order mark that is 2.2 feet above ground and still very solid.

 

 

CallawayMT

[mloser]

Dave,

 

My pic of RIDGEVIEW is the tri-station mark and the monument isn't very deep (but it sure was wide!).

 

 

I had also attempted to place this pic:

 

 

of a bench mark, (KW1093) but I put in the link and not the actual image. It is the same sort of precast monument as CallowayMT's image except mine showed a broken monument.

[NGS Surveyor]

The USC&GS specification for concrete marks is in Special Publication #247, page 92, see: http://docs.lib.noaa.gov/rescue/cgs_specpu...o247rev1959.pdf .

 

It shows the concrete of the surface mark to be four feet deep. Here is a quote from 2 pages earlier, "(a) In concrete monument .-The concrete monument is normally poured in place in a hole dug in the ground, using a top form only. The hole is dug to a depth of 3 1/2 to 5 feet (sufficient to extend below the frost line) with either a square or circular cross section (depending on shape of top form used), and about 14 inches or more in diameter..."

 

Some of the photos above may show only the top portion of a mark that broke in half. Also, note that the underground mark was just in a small mass on concrete, much smaller than the surface mark.

 

For a more modern drawing of the same type of mark see: http://www.ngs.noaa.gov/ContractingOpportunities/SOWV7.pdf, Attachment T, page 7 (or page 192 of the PDF document).

 

Just before reporting to an NGS First-Order Triangulation Party in 1978, I remember being handed SP #247 by the Chief of NGS Field Operations and told that this was my "bible" for triangulation.

GEL

[+RazorbackFan]

This one wasn't set in concrete but rather a long rod driven into the ground. I think it met it's demise with a snow plow. I found it lying in the ditch.

 

 

 

And yet another RM (GG0632) out of its natural habitiat... (Photo by tosborn)

 

[wwflover13]

While out benchmarking today, I came across "STEPHENS" (EZ1025) that a nearby resident confirmed had recently been torn out of the ground and broken in half by an electric company trenching an area for underground cables. The strange thing is, neither half of the monument had the disk in it. I can only assume that the workers chiseled out and took the disk with them once they realized what they dug up. A "destroyed" report has been sent to Deb B. through the e-mail address listed on the NGS website.