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
intoethanol, 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. Asexual 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 organically, 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 industries. 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
Department of
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