On Monday September 19th the long awaited cleaning of the quarry face finally began. Years ago the cleaning of the quarry face was an annual event for the staff. That changed when in the late 1990s the large indoor crane was damaged and could not be repaired. The crane was needed to hold the canister vacuums and get the staff to the high areas of the face. It took two people about a week to vacuum the entire quarry surface, both bone and rock. Without the crane there could be no cleaning. Of course, no cleaning was done once the building was condemned and closed in the summer of 2006.
For most of the last 18 months the quarry has been enclosed within a immense plywood and scaffold sarcophagus (see several earlier posts about that structure). This protected the fossils from damage from tools and equipment but could not be made airtight. As a result, some dust from the demolition and construction work over the last year and a half got into the box and settled on the face. In addition, some rodents and bats found the sarcophagus a comfy place to hang out and defecate in.
A short while ago the sarcophagus came down and the fossils and rock were exposed again within the building. However, quarry lacked its former splendor because of all the dust, dirt, and small bits of construction material on it. Bones could be seen but they did not stand out and the entire surface was a dull gray color.
But cleaning up was more than just grabbing a broom. The dust posed several potential threats. There was the possibility of infectious agents from the bat and rodent feces. Of greater concern was the level of radon in the dust. The quarry and its bone naturally emit radon which is a radioactive, colorless, gas byproduct of the decay of uranium. The radon particles become attached to dust particles, which if breathed in, can become lodged deep in the lungs and cause cancer years later. Fortunately, scientific testing of the dust revealed that there was little infectious threat and the radon levels were quite low.
Nevertheless, personal protective equipment was required for the cleanup. Disposable tyvek suits kept dust off the clothes. Similarly, gloves protected the hands and safety glasses did the same for the eyes.
An appropriately sized and fitted respirator with filter canisters prevented breathing in any dust. A hardhat was required against the inevitable noggin knocks.
However, once fitted out in this equipment, an employee looked eerily like a lab researcher from a biohazard facility.
|"Did anyone see where I put that vial of Ebola Reston."|
Those working from the lifts were harnessed up and leashed to the basket.
Even the vacuum cleaners were somewhat special. They needed HEPA filters to prevent the finest dust particles from being blown around the building.
The quarry face is about 50 feet tall and the upper third is nearly vertical to overhanging, so we needed to use lifts to get us up to and hold us in place while cleaning the highest levels.
The lower third of the cliff could be vacuumed from ground level.
In some places near the bottom the dirt and gravel on ledges was so thick it could be swept up and dumped into buckets.
The middle third of the cliff could be walked across with a backpack HEPA vacuum, as long as one was carefull in placing your feet.
This vacuuming was pretty successful. This is especially true for the sandstone matrix which is light gray, golden brown, purple, or green, depending on what minerals were deposited where in the quarry. It all looked a dull tan until each sweep of the vacuum revealed crisp new coloration, as can be seen in this photo:
The bones however, retained a thin layer of more intractable dust that the vacuums didn’t completely remove. This could only be removed by hand wiping each of the 1500+ bones with a damp cloth.
Surprisingly it took just five days to clean the entire 150 foot long, 50 foot high surface. That was less time than anticipated, which was a nice surprise, given the tight deadlines we were working under. The results are spectacular and the cliff face now looks better than it has in probably 15 or more years.
However, photos cannot do it justice --- so come and see it for yourself.
My heart felt thanks to all those who were involved in this effort, it could not have been done without them: April Wood, Noel Mays, Pat McElroy, Carla Lopez, Barbara Tallman, Clark Tallman, Jesse Hutchinson, Matt Mateo, Andy Mesko, Joel Brumm, Jake White, Zach Parkes, Marian Yazzie, Stuess Leeds, Zach Elkins, Angell Britt, Merlin Mott, Gary Mott, Wayne Prokopetz, and Dinosaur’s Superintendent Mary Risser.