Huge Jackets

[roger@dtgnet.com (Roger A. Stephenson)]

Greetings all,

Some of you may remember a question I posed to the list last spring
concerning the best way to flip a huge jacket, one say containing a
complete Triceratops skull.

I didn't get much help, some, but not much. It seems either no-one has
attempted this or withheld the information so we could learn on our own.
Either way we succeeded! The entire dig leadership fretted over this
problem for months, and it caused a major amount of stress.

For  the sake of those that might search the archives at some point in the
future I am going to give a summy of what we went through. I realize
different situations would require different methods but the same basic
problem remains. How to roll and palster a 2,000 Lb. specimen and keep it
intact.

Firstly, on the top portion, that was well exposed and heavily
consoilidated, we used the normal plaster and burlap separated from the
bone by tissue paper. Then we used several wooden "spines" to strenghten
and protect the upper portion of the jacket. This is all normal stuff and
left us with the problem of how to be completely sure that the skull,
matrix, and upper half of the jacket could be rolled over without it all
falling apart.

We drove a 2" steel pipe well under the skull through the matrix at several
points. The pipe would fill up with the mudstone after 4-6 inches and had
to be romoved to extract the "core". When we had made several clean holes,
or small tunnels, under the skull we pushed straps of burlap through and
tied them to the upper half of the jacket. We applied a GREAT deal of
tension to these straps, and anchored them to the top half of the jacket
using more plaster and burlap. We left this mass of plaster to "cure"
overnight. This served to bind the whole thing together.

The next day we began to undercut the skull and create as samll as possible
pedestal without endangering the skull or those of us working underneath
the huge mass. When we were confident we could roll the great jacket over
we positioned some old tires for the jacket to smash into. These served as
a brake to stop the rolling and as a cushion to absorb as much of the shock
as possible.

Four of us, equipped with heavy steel pry bars and others spotting for us,
levered the jacket towards the waiting tires. With one great push we got
the jacket moving and it went right where we wanted just like we planned.

We added some siderite nodules around the sides to steady the jacket, cut
away the burlap straps on the former underside, removed a heap of mudstone
matrix, and proceeded to encase the rest of the jacket in the usual manner
with burlap and plaster, and a few more wooden spines.

Just 2 weeks ago we recovered this monster from the field. Yes, we had
protected it from the elements with heavy tarps and allowed for air
circulation. This is where it gets real interesting. We had the use of a
great big tractor, with a big bucket on the front. Along with this bucket
the tractor had a set of clamping claws used to hold those round bales of
hay. We wrapped a chain around the jacket, and used a binder to tighten it
down securely, once it was in the bucket. The tires we had used earlier
were left in place to allow the bucket to easily slide under the jacket,
and this also worked great. Then we clamped the whole thing down with the
giant claws and the rancher headed out to the road.

Thinking the hard part was over, prematurely, we encountered another
problem. The 2,000 Lb. jacket made the tractor so front heavy it would
barely climb out of the smallest ravine, and we had to cross a few deep
ones. Luckily the tractor had "positrac" capacity, and we eventually got it
to the road.

My advice to any other field workers out there facing such a problem
consider all the possible problems such as these, and then rethink them.
What seems as though should be a simple matter is sometimes exaggerated by
even more simple obstacles. Also remember that a jacket of this size is a
dangerous object in and of itself. Nobody should be hurt collecting even
the best specimen. It took us 2+ years to get this specimen indoors, and it
still has to be transported from the ranch to our building. It may have to
wait 'til spring and the roads are free from hazards before we attempt the
final stage of this saga.

If anyone wants more details feel free to contact me off list, or by
conventional methods.

Roger A. Stephenson
Assistant Director
The Grand River Museum
503 3rd Ave East
Lemmon, South Dakota
605-374-3830
http://www.iw.net/~roger/