At the annual Gem-O-Rama gem and mineral

Transcription

At the annual Gem-O-Rama gem and mineral
The Trona
Gem-O-Rama
Field Trips
At the annual Gem-O-Rama gem and
mineral show hosted by the Searles Lake
Gem & Mineral Society (SLG&MS), the
most popular activity is to go on one of the
field trips to Searles Dry Lake, the mine
operated by Searles Valley Minerals, Inc
(SVM). The Gem-O-Rama sponsors three
completely different field trips. The show
opens Saturday morning with the Mud field
trip where collectors dig through nearly
1,000 tons of sticky black mud that is filled
with many thousands of large single and
cluster hanksite. The Saturday afternoon field
trip is to the Blow Holes where collecting is
from a nearly dry salt surface. On this field
trip everyone will find many nice crystals,
most of which are hanksite although borax,
thenardite and sulfohalite are also plentiful.
Sunday morning continues with the Pink
Halite field trip. This is to the brine pools
where many lucky collector find nice and
valuable specimens of pink halite.
Both Saturday field trips require extensive
preparation by the technicians of SVM. The
minerals in the mud lie 6 to 10 feet below
the surface and 4 to 8 feet into the brine.
To make these specimens available, SVM
technicians use a large backhoe to dig
the crystals and load them into trucks. The
trucks carry the mud to the collecting area
where they dump and spread the mud. This
collecting area was selected because there is
enough hard surface for all of the collectors
to park their cars close to the mud piles.
Preparations for the Blow Holes field trip
must begin several weeks in advance. This
is when SVM technicians drill up to 16 holes
into the dry salt surface. These holes are
16 inches in diameter and 42 feet deep.
Next the holes are cleaned to ensure that
there is a completely open hole. Then four
or 5 days before the show, the SLG&MS
purchases up to 1,200 pounds of explosives
through a licensed commercial blaster
who also sets the charges and detonates
them. These explosives are set and then
detonated between 20 and 42 feet below
the surface where there is a thick bed of
hanksite and other mineraline crystals. This
blasting loosens the crystals so that the next
step in the process can easily bring them
to the surface. To bring them to the surface
SVM technicians use what is called an “air
lift pump.” This pump consists of a 10 inch
diameter pipe that has been lowered to
the top of the loosened crystals and an air
compressor that injects compressed air into
the bottom of pipe. Because the end of the
pipe is deep below the brine surface, the air
rushes rapidly up to inside of the pipe. As
it does so, the air carries brine with it, and
this rush of brine lifts the loosened crystals
to also bring them up the pipe. At the top
of the pipe there is an elbow and this turns
the air-brine-crystal steam to make it shoot
out to the side. Then by turning the pipe,
the crystals can be spread across the salt
surface.
The Blow Hole field trip includes a
demonstration the air lift pump. During this
demonstration visitors can watch as SVM
technicians remove the loosened crystals from
the bottom of one of the holes. In addition to
letting our visitors see how these minerals are
made available to collectors, another several
tons of crystals are made available to
visitors. For safety reasons, we ask everyone
to stand back until the demonstration is over.
But once the demonstration is over all, of the
spectators become avid collectors, rushing in
to see if they can find that huge crystal they
saw come out of the end of the blow pipe.
Collectors during Blow Hole field Trip
Watching the Blow Hole Demonstration
Blow Hole Demonstration
Collectors on Crystal Pile Deposited by Blow Hole Demonstration