Can
high Purity Solar Grade Polysilicon Be Co-produced as a
By-Product of “Diatomic Energy” Algal Biomass Biogasoline
and BioDiesel Production?
Pure
“polysilicon is a high value commodity in the Solar PV and
semiconductor industries.
http://www.eetimes.com/news/semi/showArticle.jhtml?articleID=175801721
Electronics
Engineering Times
(01/05/2006
4:51 PM EST)
SAN JOSE, Calif. — Prices for
polysilicon are expected to see further increases this year
and next amid ongoing shortages for the materials, warned
an analyst.
“The rapid increase in solar
cell production, and rising IC unit volumes, triggered a
polysilicon shortage, [are] forcing solar cell manufacturers
to pay significantly higher prices to secure silicon supply,”
said Jesse Pichel, an analyst with Piper Jaffray Inc., an
investment banking firm.
“The contract price of polysilicon
has soared 80 percent in the last 18 months to $60/kg, and
we anticipate further increases to $80/kg in 2006 and more
in 2007,” he said in a new report.
Polysilicon contracts are sold
out through 2007; spot prices for these materials recently
reached $140/kg, he added.
Leading polysilicon vendors
cannot keep up with huge OEM demand and are reportedly sold
out of these materials for the next two to three years,
according to industry sources.
Polysilicon, a material that consists of multiple small
crystals, is used to make silicon wafers, solar cells and
other products.
After sizzling growth in recent
times, the solar energy market is projected to dim and “hit
the wall” for panel, equipment and materials vendors in
2006, according to the analyst.
The projected slowdown in the
solar market for 2006 is mainly due to ongoing and severe
shortages of polysilicon, Pichel said. Growth is projected
to resume in 2007, when more polysilicon supply becomes
available, he
said.
Chip and solar-panel makers
won’t admit it, but many are feeling the brunt of the supply
problems. For example, SunPower Corp., a solar panel maker
backed by Cypress Semiconductor Corp., buys mono-crystalline
ingots for 80 percent of its production requirements, and
cut wafers for 20 percent, according to the analyst. It
has multiple suppliers providing raw polysilicon, contracted
wafer production and ingots.
Through 2005, SunPower contracted
at $108/kg per ingot based on polysilicon priced at $50-to-$55/kg,
according to Piper Jaffray. “We believe that the contract
price rose to $115/kg per ingot in December 2005, based
on polysilicon priced at $65-to-$75/kg,” according to the
report.
“For 2006, we believe SunPower
has contracted at $145/kg per ingot and $85/kg for polysilicon,”
the report said. “Although SunPower has [about 75 megawatts]
of polysilicon under contracts and purchase orders, we believe
that 23 megawatts of its 2006 needs are at risk. So, SunPower
is likely to tap the spot market for supply.”
For 2007, SunPower currently
has about 110 megawatts of polysilicon allocated by vendors,
and 75 megawatts under contract and purchase orders. “Polysilicon
prices should remain high for the year, with spot pricing
expected to exceed 100/kg and ingot pricing more than 150/kg,”
according to the report.
As some members
may know, I have been actively developing methods to
cultivate, certain
high oil content diatoms, to make "Diatomic Energy"
from algal biomass derived biogasiolines, and BioDiesels.
This serendipitous ALT/Energy quest began, when Mother Nature
decided to "foam" The Huge James River in Richmond
VA in the summer of 2006.
SEE:
http://www.fossilfreedom.com/summer.html
and:
www.biodieselnow.com/forums/thread/32909.aspx
As
a result of that quest, I now have a diatom growing in captivity,
that makes oils suitable for biodeisel production, and sugars
and starches, suitable for biological fermentation into
ethanol, acetone and butanols. Butanols are one excellent
form of non-ethanol biogasoline (among many), which are
a direct replacement for petroleum gasoline with almost
no pollution or toxicity. Also biogasolines, and biodiesels,
are net carbon neutral, and do not cause global warming.
Many researchers, have been looking at algae, as a petroleum
energy replacement.
Despite
what you may have learned in school wrongly, no dinosaur
ever contributed a single BTU of energy content to any petroleum
anywhere!
Dinosaurs,
as well as mammals, and humans, are net energy consumers.
They do not photosynthesize, and therefore do not trap solar
energy and
store it.
Plants
do that by photosynthesis.
The
energy density of petroleum originally came eons ago, from
photosynthesis
of plants alone!
Most
of the petroleum energy ever produced, was created by the
decaying corpses of photosynthetic plant algae, sinking
to the bottom of the sea, and getting trapped in other sediment
to form oil layers, in sedimentary rock basins.
Replacing
all petroleum, with energy derived from algal-culture, is
therefore the most direct route. Algae can grow a new crop
in as little as three days! All we need do, is somehow,
speed up the oil producing rate by several orders of magnitude,
to create a petroleum replacement in short time spans, of
weeks, instead of eons. One of the real beauties of that
approach, is that we can just build photobioreactors, and
create a precisely controlled "Perfect Ecological
Niche" environment, and our algae will go right to
work, doing
what comes naturally to them. Give
then the right niche, and they do all the work!
Diatoms
are just a subset of algae. Not only do they make fuel biomass;
they make opal (pure polysilicon) frustules (half-shells)
too!
When
I developed my "Diatomic Energy" breeder feeding
program, I had to feed sodium silicate to my diatoms to
avoid silicon starvation. Silicon starvation would stress
the diatoms and make them begin TAG synthesis (oil production)
to save up energy for "Hard Times" To "Breed"
new diatoms in my "Diatomic Energy" breeder photobioreactors,
I had to encourage sexual reproduction to make nice new
full-sized opal polysilicon frustules for the new "highly
silacious"
and extremely sexually active juvenile diatoms.
Think
of this like the old Star Trek Episode entitled "The
Trouble With
Tribbles" The
trouble with Tribbles was that they "were born pregnant!"
That's
is just about the case with sexually reproducing diatoms.
Asexually
reproduced diatoms use the parent's old frustules as
a mold-template
to produce a new, slightly smaller copy. So each asexual
diatom is smaller than a asexual parent. A sexual diatoms
grow very fast, creating blooms, but with diminishing silicon
returns.
To
make full sized fresh opal polysilicon frustules, sexual
reproduction is the only way. (but you already knew that,
didn't you). In order to grow diatoms, I found that
I could control the growth process of the diatoms by intentionally
regulating the available soluble silicon, as sodium silicate
(water glass), as well as trace elements like phosphorous,
boron, strontium, molybdenum, selenium and several others.
If
"Cultured Diatomic Energy" biomass production
methods were adopted, using diatoms as the photosynthetic
organism, (and by substituting easily removed or solar non
active trace elements in the
diatom diet), it may be possible to develop a "diatomic
energy process"
that would create and preserve the diatom frustules as an
rganically,
and biologically, grown, ultra pure "opalene solar
grade polysilicon!"
Diatoms
use phosphorous to grow their phospholipid membranes, and
quite probably avoid depositing it in the frustules, (especially
if the phosphorous supply were intentionally very limited),
as it is needed for photosynthesis.
If
boron were excluded from the growth photobioreactors, there
would be little or no boron to contaminate the silicon frustules.
The two principle difficult to remove contaminants in sand
may not be a problem at all in "Cultured Diatomic Energy"
solar grade polysilicon cultivation.
By
using the nascent "Diatomic Energy" Biofuels industry,
it seems we
could possibly co produce the following value added commodities:
1)Biogasoline
fuels
2)Biodiesel
fuels
3)Vegetarian
Grade Omega-3 heart healthy oils
4)High
quality protein meal to feed to animals or humans
5)Nitrogen
and phosphorous fertilizers for recycling in agriculture,
or algae-culture
6)
Biologically pre-purified Solar grade diatomic opal polysilicon
It
would be a real boost, to both the Solar PV industry, AND
the biofuels industries, if such an important value added
synergy could be developed, to reduce costs, and increase
profits, in both iindustries.
Low
costs and genuine profits, are the drivers, and the capital
source, for the much needed, geometric expansion, in both
ALT/energy
industries.
Hog
farmers brag that they "use everything but the oink"
Diatoms
are silent, but they do "glint" in the sunlight!
Perhaps,
we, in the nascent biofuels industry, can even find a way
to put that glint to a very good use!"
With Best regards
FREE ENERGY
Patrick Ward
Richmond VA
fossilfreedomATyahoo.com
fossilfreedom@yahoo.com
fossilfreedomATyahoogroups.com
fossilfreedom@yahoogroups.com
biogasolineATyahoo.com
biogasoline@yahoo.com
biogasolineATyahoogroups.com
biogasoline@yahoogroups.com
fossilfreedomATgmail.com
fossilfreedom@gmail.com
http://www.fossilfreedom.com
FROM:
http://academic.evergreen.edu/g/gutholmj/applied_geology
/diatomite/body.html
INTRODUCTION
Quite a few years ago, I used to use diatomaceous earth
for filtering water in fish aquariums. It makes an excellent
filter medium that is capable of removing the smallest particles.
It can even filter out parasites. Although I knew that it
was produced from the fossil skeletons of an aquatic organism,
I never gave much thought to everything that was necessary
to develop, mine, and process this material, As far as I
was concerned, it just came from a store shelf. After having
an opportunity to see the Celite Corporationís diatomite
mine in Quincy, Washington, I became fascinated with all
that must have occurred to create the deposits that they
were mining and how they processed it to achieve the end
product. It is the goal of this paper to answer those questions.
LIFE
OF DIATOMS
Although
diatoms appear plant like, scientists have determined that
these single-celled organisms are neither plant nor animal.
Diatoms are classified with the single-celled protozoans,
molds, and fungi into a separate group called the Kingdom
Protista (Burnett,
1993). Diatoms live in many diverse environments.
They can be found in the oceans, lakes, streams, salty inland
seas, and brackish estuaries. Diatoms can be found in almost
any body of water where there are adequate nutrients. Most
diatoms use photosynthesis to produce their energy, so they
also need sunlight. There are some diatom species that do
not contain chlorophyll. These diatoms must acquire energy
by some means other than photosynthesis. Although diatoms
can live in environments with a wide range of temperatures,
they are more prolific in colder waters. They are very abundant
in the polar oceans. Most diatoms live in the open water
column at or near the surface (Werner,
1977). When they die they sink to the bottom. The
soft tissues decay leaving behind a fossil skeleton.
Most diatom fossils are found in Eocene and Miocene
sedimentary rocks. The oldest known diatoms that have been
definitely identified and dated are from the Lower Cretaceous
(Burnett,
1993). Fossil diatoms which are subjected to pressure
may recrystallize into metamorphic rock and this may explain
why older fossils are not found (Compton,
1991). There is be an active debate in the scientific
community, as to when diatoms first appeared. In 1951 G.
Dallas Hanna, a pioneer in the study of diatoms, speculated
that the history of diatoms must go back farther than the
Cretaceous. His assumption was based on the fact that by
the time of the Cretaceous, diatoms were already very abundant,
highly organized and of many diverse forms (Burnett,
1993). Recent work, using inferred phylogenetic
trees from 18S rDNA sequences, indicates that diatoms have
their origins somewhere around 238 Ma to 266 Ma.
Diatoms consists of a membrane supported and protected
by two half-cell walls or valves. The two valves and their
connecting band form the diatoms silica skeleton called
a frustule. These two valves, the epitheca and the hypotheca
are different sizes. The epitheca, being the larger of the
two, slightly overlaps the rim if the hypotheca like a lid
(Burnett,
1993). The organisms extract silica from the water
to build their frustule. Typically, the frustules exhibit
complex lattice-work patterns and partitions of great variety
and complexity. Since the total thickness of the each valve
wall is only a few microns, it results in an integral structure
that is highly porous on a microscopic scale (Hanna,
1951). The frustule of most diatom species are between
50 and 150 microns in diameter (Benton,
1983).
The frustule, or silica skeleton of a diatom is
made up of amorphous silica which has the same chemical
composition as opal (Hanna,
1951). The chemical formula for amorphous silica
is SiO2ïnH2O. The water content usually
ranges from four to nine percent, but it can be as high
as twenty percent. Although this form of silica does not
form in a crystal lattice the structure is highly ordered.
Individual silica spheres arrange themselves in hexagonal
or cubic closest packing, water and/or air taking up the
space in the voids (Klein
and Hurlbut, 1985).
Diatoms can reproduce both sexually and asexually.
During sexual reproduction diatoms produce non-siliceous
gametes which are released into the surrounding water. When
two gametes join together they form a complete zygote, enlarge,
and build a frustule. During asexual reproduction the two
halves of the frustule separate and each half generates
a new hypotheca. When the smaller hypotheca from the original
individual generates a new hypotheca, it becomes the epitheca,
or larger half. This causes the new individuals to get progressively
smaller. Although asexual reproduction does cause the line
to become progressively smaller, it does allow diatoms to
reproduce very rapidly in blooms. This allows them to quickly
take advantage of favorable changes in environmental conditions
such as an increase in dissolved silica. Sexual reproduction
then serves not only the purpose of combining the genetic
material from different individuals, it also allows the
progeny of asexual reproduction cycles to produce offspring
that will grow to full size (Werner,
1977).
There is a wide range of estimates on the number
of diatom species that have existed. Many estimates place
the number as high as 100,000 to 200,000 different species.
Of this great number only about 25,000 bona fide species
have been actually cataloged and described (Werner,
1977).
FORMATION
OF DIATOMITE
Diatomite
is the specific name given to fossil diatom deposits that
are large enough and pure enough that they are of potential
commercial value (Benton,
1983). Although diatoms inhabit many different environments
throughout the world they are in most instances, not accumulating
in the concentrations that were necessary to form the Miocene
and Pliocene age deposits that are being mined throughout
the world today (Burnett,
1991).
Two primary factors that affect the formation
of diatomite deposits are the rate of accumulation of diatoms
frustules, and the rate at which other sediments are accumulating
in conjunction with them. The amount of available silica
in solution is typically a limiting factor in the reproductive
rate of diatoms and therefore controls their rate of accumulation.
This may explain why most of the known diatomite deposits
are Miocene and Pliocene in age. This was a time of increased
volcanism throughout the world (Hanna,
1951). Most sources of silica are not very soluble
in water, but the silica in volcanic ash dissolves comparatively
easily (Burnett,
1993). Considering the extent of volcanism during
the Miocene and Pliocene and the large populations of diatoms
that must have been living, diatomite is less abundant than
might be expected. Diatom fossils are present in many sedimentary
rocks of this age, but other sediments accumulated in conjunction
with them in such great quantities that the diatom fossils
only comprise a small proportion. Two deposits of particular
interest are the Celite Corporationís mines in Lompoc, Ca.
and Quincy, Wa. The Quincy deposits are of interest because
I have been to the mine. The Lompoc deposits are of interest
because of their tremendous size and contribution to global
production.
In the area of Quincy, Washington two separate
Miocene diatomite deposits have been mined commercially
(Benton,
1983). At various times throughout the Miocene,
lava flows of the Wanapum Basalt blocked off streams channels
causing lakes to form (Niemi, 1981). These lakes provided
an ideal environment for the growth of diatoms. The volcanic
eruptions that provided the lava to create the lakes would
have also contributed volcanic ash to the drainages that
fed the lakes. The volcanic ash provided an abundant source
of silica, which is needed for the rapid growth of diatom
populations. Iron can also be a limiting factor in the growth
of diatoms. The lakes were formed in basalt which is relatively
high in iron and weathers easily. Many such lakes probably
formed throughout Eastern Washington at this time. Of these
lakes, most would have received large enough amounts of
terrigenous sediments. The sedimentary rocks that formed
in most of these basins may contain fossil diatoms, but
not in sufficient concentrations to be considered diatomite
(Mackin,
1961). Only the lakes which received minimal amounts
of terrigenous sediments formed diatomite deposits. The
Squaw Creek Diatomite and the Quincy Diatomite both formed
in these types of lakes (Niemi,
1981).
The Squaw Creek Diatomite occurs at the base of
the Rosa Member of the Wanapum Basalt. The Squaw Creek Diatomite
is the older of the the two deposits in the Quincy area.
This deposit was formed during a period of volcanic inactivity
after the formation of the Frenchman Springs Member. Basalt
flows of the Rosa Member capped off the deposit probably
while it was still being formed. This is evidenced in the
Rosa Peperite where basalt flowed into the diatomaceous
sediments which were apparently young and not well consolidated.
The Quincy Diatomite occurs at the base of the Priest Rapids
Member of the Wanapum Basalt (Carson,
et al, 1987). This deposit
is currently being mined by the Celite Corporation.
The Celite Corporation also operates the larger
of the two diatomite mines in Lompoc, California. The Lompoc
deposits are the worlds largest source of diatomite being
mined today (Burnett,
1991). The diatoms of the Lompoc area occur in the
Sisquoc and Monterey Formations which are upper Miocene
to Lower Pliocene in age. These deposits were formed during
a six or seven million year period that spans the Late Miocene
to Early Pliocene (Compton,
1991). Various parts of the Sisquoc Formation are
discontinuously exposed at the surface for more than 15
miles in a series of closely-spaced folds. Individual diatomite
beds range from only a few centimeters up to 15 meters and
the entire deposit is hundreds of meters thick (Burnett,
1991).
During the Late Oligocene and Early Miocene the
intersection of the East Pacific Rise with the North American
Plate created a region of extensional tectonic activity
along the coast of Southern to Central California. This
tectonic activity created the sub-marine basin in the Pacific
ocean, adjacent to the coast. The sediments that make up
the Sisquoc Formation and the underlying Monterey Formation
were deposited in this basin (Compton,
1991). Throughout the remainder of the Miocene siliceous
frustules of diatoms were deposited in the basin with very
little accumulation of terrigenous sediments. The large
populations of diatoms necessary to form these deposits
were enhanced by two additional factors. First, as mentioned
earlier the Miocene was a period of increased volcanism.
Volcanic activity contributed ash to the water, increasing
the dissolved silica. Second, the period from 16 to 12 million
years ago represents a major global cooling event (Flower
and Kennett, 1993). These cooler temperatures would
have been favorable for the growth of large populations
of diatoms.
During the Early Pliocene, the Santa Ynez Mountains
were uplifted adjacent to the basin. This resulted in a
quadrupling in the rate of overall sedimentation, most of
which was terrigenous on origin. The uplift of the Santa
Ynez ended the formation of the relatively pure diatomite
deposits by contaminating the basin with large amounts of
terrigenous sediment being eroded off the newly formed mountains
(Compton,
1991).
This dramatic increase in sedimentation greatly
increased the overburden pressure being applied to the Monterey
Formation. The increased pressure coupled with a high geothermal
gradient, probably brought about by thinning of the crust
and an upwelling of the asthenosphere in this extensional
environment, caused diagenesis of the diatomite in the lower
sixty to seventy percent of the Monterey Formation. This
process transformed the diatomite to cristobalite. The remainder
of the Monterey Formation and the Sisquoc formation were
not buried deep enough or heated sufficiently for diagenesis
to occur. From the Early Pliocene to the late Pleistocene
the Monterey and Sisquoc Formations were tectonically folded,
tilted and uplifted. Diatomite was then exposed at the surface
by the erosion of overlying sediments (Compton,
1991).
MINING
AND PROCESSING
There are currently 12 diatomite producing facilities in
the United States which are operated by six different companies.
Although underground mining of diatomite has occurred in
the past (Oakeshott,
1957), all current U.S. mining is done by open pit
methods (Lemons,
1996). All of the active diatomite mines is the
U.S. are freshwater lake deposits except the marine deposit
at Lompoc, California. The mining and processing of diatomite
is unusual in that care must be taken not to destroy the
structure of the individual diatom frustules. Diatomite
can not be subjected to excessive attrition in the process
of milling and conveying. Unprocessed diatomite is referred
to in the industry as crude. It is typically mined using
bulldozers and trucks (Oakeshott,
1957).
The crude is transported from the mine to processing
plants which are usually located nearby. Crude has a density
of between 320 and 640 kg. per cubic meter and a moisture
content of thirty to sixty percent. It is first crushed
to a size of about one to two centimeters and furnace dried
to reduce the moisture content to about fifteen percent.
Diatomite is usually made up of a number of different species
of diatoms. After initial drying the crude is cleaned and
sorted by particle size. This is done in series of cyclone
classifiers. The classifiers use hot gasses to sort the
different particle sizes and further dry them at the same
time.. After being sorted and dried the crude may be bagged
and sold as natural diatomite. Although the diatomite has
been sorted, each grade still has a considerable size distribution.
For this reason most diatomite products are further processed
(Benton,
1983).
Diatomite products that are further processed are called
calcined and flux calcined diatomite. Most diatomite products
are used in filtering applications. With a large particle
size distribution, the smallest of the particles occupy
space between larger particles. This reduces the rates of
flow through the filter. The purpose of calcining is to
reduce the particle size distribution. The use of the term
calcined is ingrained in the diatomite industry and markets
so it is used frequently, but diatomite is actually sinterized
not calcined (Benton,
1983).
Sintering reduces the size distribution by melting
the smallest particles together. To produce calcined diatomite
the natural product is heated to between 900° C. and 1100°
C. The high temperatures burn off organic contaminants,
and shrink and harden the individual particles. Some of
the diatom frustules are sintered into small clusters. The
resulting calcined diatomite has a density of about 125
to 150 kg. per cubic meter. Flux calcined diatomite is produced
using the same methods except a fluxing agent is added before
heating. Soda Ash in concentrations of between three and
seven percent is usually used as the fluxing agent. The
diatomite is heated to around 1200° C. slightly higher than
for straight calcined products. Varying the temperature,
amount of flux added and the processing time controls the
particle size distribution. Flux calcined diatomite has
a wide density range depending on the processing. It varies
from about 150 to 300 kg. per cubic meter (Benton,
1983).
THE
MINERAL COMMODITY
In 1996 the U.S.G.S.
conducted a production survey of all twelve of the U.S.
producers. The annual production in the United States for
1995 was 687,000 tones (table
1)
(Lemons,
1996).
This represents an increase of twelve percent from 1994.
Although domestic production did increase in 1995, it has
not increased significantly over the last 30 years. An extrapolation
from the 1991 Minerals Commodity Report on Diatomite published
by the California Department of Conservation projected 1995
production at 768,000 tonnes. This is 81,000 tonnes, or
twelve percent higher than the actual 1995 production reports.
During the four years since the 1991 report was published
world production of diatomite has decreased by 240,000 tonnes
(Lemons,
1996).
As world production and probably demand have decreased,
U.S. production has increased slightly, but it is not increasing
at even the modest rates projected only 4 years earlier.
Diatomite has been used in hundreds of applications since
it was first commercially mined in the 1800ís. In 1995 eighty-four
percent of all diatomite produced in the U.S. was used in
three principal areas (table
2); as a filter medium, as a filler, and as an insulator.
seventy percent of all production was used in filtering
applications (Lemons,
1996). These applications vary widely from filtering
beverages and food products to swimming pools. As a filler,
diatomite is used many applications primarily because it
has a low density and is relatively inert. It is used as
an filler/extender in paints because of its unique ability
to trap pigments helping to distribute the color evenly
throughout the mixture. Diatomite is also used as a filler
in pharmaceuticals and many other chemical applications
(Burnett,
1991). Low-grade diatomite that contains enough
clay to act as a bonding agent has been used for manufacturing
bricks. This was one of its first commercial applications
(Oakeshott,
1957).
The
price of diatomite varies widely depending on the purity
and the level of processing necessary to produce the final
product. In 1995 the average U.S. price for diatomite used
in various applications ranged from $113.77 per tonne to
$302.29 per tonne (table
3) (Lemons,
1996). Prices have remained stable for the last
few years. Processing of raw crude is the most costly part
of diatomite production. It comprises sixty percent of the
total direct cost to mine, produce and ship diatomite products.
Most of this expense is related to the cost of energy needed
for drying and sintering. Thirty percent of the total direct
cost goes to packaging and shipping, and amazingly only
ten percent for the actual mining (Benton,
1983).
World
reserves of diatomite are estimated at 800 million tonnes
(Kesler,
1994). At current rates of consumption this
is enough to last for almost 600 years. The Celite Corporationís
mine at Lompoc, Ca. covers an area of eleven square kilometers
to a depth of 200 meters. This mine alone could probably
meet world demand for the next 150 years. One of the threats
to reserves and the reserve base is growing urbanization.
Land covering otherwise commercially mineable deposits in
Ventura, Los Angles and Orange counties has been developed
for industrial and residential use. It is unlikely that
these deposits will be extracted in the foreseeable future
(Burnett,
1991).
ENVIRONMENTAL
CONSIDERATIONS
In
any mining operation care must be taken to preserve and
restore the natural environment. Because natural diatomite
is composed of mostly amorphous silica it does not present
as serious an environmental or health risk as crystalline
forms of silica. Unlike crystalline forms of silica, diatomite
is not classified as a potentially carcinogenic (Burnett,
1991).
Reclamation is an important part of commercial mining. Public
perception drives public policy. This becomes especially
important in areas like Lompoc, Ca. where mining is occurring
in close proximity to a large, growing urban center. Diatomite
is essentially inert and therefore poses little or no threat
to the environment in both active and reclaimed mines. Because
of the high absorption capacity of diatomite, it retains
moisture which aids in the re-vegetation process where mine
pits are being reclaimed. This high absorption capacity
may also help in controlling runoff of precipitation. This
would significantly reduce erosion, which can be a difficult
problem when trying to restore topography. In Los Angeles
County a diatomite quarry on the Palos Verdes Peninsula
was closed in 1956 after 27 years of operation. After being
closed the quarry pit served as a sanitary landfill for
8 years. The county then created the South Coast Botanic
Garden over the landfill (Burnett,
1991). Based on my own observations at the Celite
Corporationís mine in Quincy, Washington, it appears that
the Celite Corporation is doing an excellent job returning
the land to its original state.
Safe working and living environments can be maintained in
and around diatomite mines by reducing the amount of material
that becomes airborne, and controlling exposure times. In
the processing plants, workers are exposed to diatomite
products that have been sinterized. In the sintering process
some of the amorphous silica recrystallizes to cristobalite.
This mineral is considered to be carcinogenic. When Inhaled
in sufficient quantities, over prolonged periods, it is
known to cause fibrotic lung disease. By maintaining adequate
ventilation, keeping work areas clean, and using respirators,
health problems of this type can be eliminated. A twenty-one
year long study reported on by the Mansville Corporation
(Celite Corp.) demonstrated that by taking these precautions,
health problems related to fibrotic lung disease can be
practically eliminated (Benton,
1983).
REFERENCES
Burnett,
J. L., 1991, Mineral Commodity Report -Diatomite-: California
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