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From the earliest planning stages of Nemo, meticulous
recovery has been the guiding principle of the Central America project. Working
around the fallen timbers and tons of iron of a historic wooden shipwreck
requires the ability to perform heavy work-lifting and moving unwieldy material
and managing complex, multilayered excavation areas. Recovering coins and
ingots from this complex environment also requires great delicacy and surgical
precision. Valuable coins, for example, must be handled, often individually,
with utmost care to preserve their exact condition and to avoid disturbing the
rest of the deposit.
Nemo recovers large ingots with
padded fingers, but the robot recovers individual coins with a suction-picker.
Using the 3-D monitory aboard the research vessel a mile and a half above to
gauge distances to fractions of an inch, Nemo's operator carefully manipulates
this device as close to the surface of a coin as possible and then activates
the suction to hold the coin against a rubber cup. He then guides Nemo's arm to
carry the coin to a nearby tray, and releases it into a numbered slot. Sitting
nearby in the RV control room, the videographer records the entire process
while the dive coordinator logs in the time and the number of the coin. Once
the tray is filled, Nemo places it inside its retractable storage drawer for
the trip to the surface.
When coins
are clustered together, the pilot follows a different procedure, using Nemo to
surround the cluster with a padded frame, which is then filled with a special
silicone gel. Thus held fast, the coins are brought to the surface. The
congealed silicone is later peeled away, releasing the individual coins.
When Nemo surfaces with the gold, the collection trays go to the ship's
lab. There team members are able to examine the coins and ingots closely,
catalogue them in detail, and store them for transport back to labs on shore.
Coins are usually protected in the plastic sleeves used by numismatists,
although stable clusters are sometimes left encased in their silicone.
Individual containers hold ingots, which are carefully wrapped in cloth. The
dust and nuggets suctioned up from the ocean floor by the sea-vac are panned
from the sediment and placed in numbered vials. |
