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Title: Glass


1
Glass
  • Kay Tam
  • Professor Raquel R. Pinderhughes
  • Urban Studies Program
  • Race, Poverty and the Environmental
  • San Francisco State University
  • Spring 2003

2
Introduction
  • This presentation focuses on glass.
  • It is designed to interpret the potential
    impacts of the processes associated with glass.
    It takes you through the cradle to grave
    lifecycle of glass, paying particular attention
    to the social, environmental and public health
    impacts of these processes.

3
Presentation organization
  • We start by looking at the natural resources for
    making glass.
  • We then go to the glass making processes and its
    utilization.
  • This is followed by the disposal of glass waste.
  • I will analyze the social, environmental and
    health impacts associated with each processes
    throughout my presentation.
  • Lastly, I will talk about the importance of
    environmental justice in the life cycle of glass
    and discuss with you how can we address the
    problems.

4
Now, we start by looking at the natural resources
for making glass.
  • Distribution of natural resources
  • Formation
  • Purposes for utilization
  • Extraction process
  • Environmental and Social effects of extraction
    process

5
Natural Resources
  • Silica sand 72
  • Soda Ash 17
  • Lime 5

17
5
72
6
6
Silica Sand
7
Silica Sand
  • Three of most common rock forming minerals on
    earth
  • Chemically named quartz sand / rock crystal
  • Properties
  • Extremely heat durable
  • Chemical stack resistance

8
Formation of Silica Sand
  • Naturally
  • Mechanical chemical weathering of
    quartz-bearing igneous metamorphic rocks
  • Chemically weathering
  • Less stable minerals
  • break down to become silica sand
  • More stable minerals
  • release to environment
  • Carry by wind / wave
  • Sort by wave stream action to form pure silica
    sand

9
Location Integration of Silica Sand
  • It is found below thin layers of overburden
    soil as unconsolidated deposits
  • It is abundant resource on earth crusts (44) and
    occur throughout the world.
  • Best known place in U.S.
  • NE of town of Hudson Bay along the Red Deer River

10
World resources of Silica Sand
  • Silica sand resources is abundant on the world.
  • Its extraction is limited by
  • geographic distribution
  • quality requirements for some uses
  • environmental restrictions
  • Extraction of theses resources is dependent on
    whether it is economic and are controlled by the
    location of population centers

Fig. 1
http//minerals.er.usgs.gov/minerals/pubs/commodit
y/silica/780397.pdf
11
Purposes for the Utilize of Silica Sand
  • History
  • Glass making metallurgical activities few
    thousands years BC ago
  • Key raw material in ceramics, foundry glass
    industrial revolution
  • Today
  • Glass making, foundry casting, ceramics,
    filtration, specialist building applications,
    leisure ( e.g. golf course), filters in numerous
    products, plastics, the manufacture of chemicals,
    metal refractory, as addictives in
    horticultural agricultural products
    simulating oil production

12
Purposes for the Utilize of Silica Sand Cont
  • Important for todays information technology
  • Raw material for silicon chips
  • Plastics of computer mouses

13
Which communities depend on silica sand?
  • Every communities depend upon it for different
    purposes
  • Especially important for developing developed
    countries
  • For further technological improvement
    development

14
Extraction of Silicon Sand
  • Stripping of overburden (topsoil vegetation) by
    bulldozers scraper
  • Wet separation by washing the sand, passing
    through screens to remove roots other organic
    matter
  • Gravity separation to separate silica sand from
    regular sand
  • Finished silica sand is transported by trucks to
    plants for processing
  • Oversized materials residual clay are returned
    to mined pits

15
Soda Ash
16
Soda Ash
  • Anhydrous sodium carbonate
  • Texture soft
  • Color grayish white
  • Appearance lump / powder in nature

17
Formation of Soda Ash
  • Naturally
  • Erosion of igneous rock form sodium deposits
  • Transport by waters as runoffs collect in
    basins
  • When sodium comes in contact w/ CO2, precipitates
    out sodium carbonate

18
Location Integration of Soda Ash
  • Integrated as sodium rich waters (brines) /
    extensive beds of trona interbedded w/ sodium
    minerals
  • Large soda ash deposits
  • U.S, Mexico, Canada, Kenya, Botswana, Uganda,
    Peru, Germany, India, Egypt, S. Africa Turkey
  • Worlds largest trona deposit
  • Green River Basin of Wyoming
  • estimate to have 47 billion tons of soda ash

19
U.S. soda ash deposits
  • Owens Lake Searles Lake
  • Estimates to have 815 million of soda ash

Worlds largest trona deposit
Fig.2
www.ansac.com/100_our_story/ 103_supply.asp
20
Trona Deposits of California
Owens Lake
Fig.3
Fig.4
Trona mine at Searles Lake
21
Purposes for the Utilize ofSoda Ash
  • History
  • Early Egypt make glass soap
  • Early Roman make glass, bread pharmaceuticals
    (medicine) purpose to cure choric skin rashes

22
Purposes for the Utilize ofSoda Ash Cont
  • Important merchandise for U.S.
  • Glass fiber manufacture
  • Cleaning preparations
  • Petroleum refining
  • Metallurgical refining
  • Removal of sulfur from smokestack emissions (3)
  • Distributors (5)
  • Metal refining
  • Glass manufacture (49)
  • Chemical production (27)
  • Mineral processing in mining
  • Pulp Paper manufacturing
  • Sodium compounds manufacturing
  • Soap detergents (11)
  • Water treatment (2)
  • Textile processing

23
Export of Soda Ash of AmericanAccording to the
U.S Geological Survey, Americas soda Ash
production is approximately 11.5 million tons/
year, of which 4.5 million tons are exported
Asia
Fig. 5
www.isonex.com/glass_article_5-97.pdf
24
Extraction of Soda Ash
  • Quarrying of trona bed that contain sodium
  • Human 1st recorded extraction of soda ash ocurred
    during discovery of Wyoming trona deposit
  • Could be manufactured synthetically through
    Solvary process by using salt, ammonia
    limestone

25
The Solvay process for the manufacture of Soda
Ash (NaHCO3).
Fig.6
cwx.prenhall.com/petrucci/medialib/
media_portfolio/22.html
26
Lime
27
Lime
  • Include hydrated lime quicklime
  • Only quicklime can use to make glass

28
Location Integration of Lime
  • Underneath the topsoil , ach, siltstone
  • Associated in
  • Limestone
  • Marine organisms on seabed e.g. seashells

29
Location of rich Limestone deposit in the
world
  • North South Islands of New Zealand

www.med.govt.nz/crown_minerals/ minerals/gnsmaps/
Fig. 8
30
Export of Lime
  • 56 of lime in U.S. is produced at companies in
    Alabama, Missouri, Ohio, Texas, Kentucky and
    Pennsylvania (about 11.5 millions tons annually
  • Other nations producing lime for export
  • Canada, Mexico, China, France, Belgium, Brazil,
    Germany, Italy, Poland, Romania, the United
    Kingdom and Japan.

31
Formation of Lime
  • Marine organisms dissolve CO2 extract Calcium
    from seawater to from calcium carbonate
  • Buried under sediments of seabed after death
  • Limestone formed under heat pressure on the
    remains of marine organisms

limestone
32
Purposes for the Utilize ofLime
  • Historical Use
  • Ancient Egyptian civilization used lime to make
    plaster and mortar.
  • Nowadays
  • Use extensively for glass making, the pulp
    paper industry steel mills
  • Other uses municipal industrial water /
    wastewater treatment, as an addictive for road
    stabilization construction projects
  • In U.S., more than 90 of lime production is for
    chemical and industrial uses

33
Extraction of Lime
Initial extraction process
  • Quarry of limestone at trona bed
  • Then, transported to crush plants by trucks /
    rail
  • Undergo Calcination process
  • heating limestone or chalk (Ca3CO2) in kiln till
    900 degree celsius
  • CO2 is emitted in this process and calcium oxide
    (lime) is produced.

Blocks Ready to Saw
Chopped into Blocks
Transport to processing factories by truck
Calcination Process
Processed Lime
34
Effects pose by the Extraction of Mineral Sites
for making glass
  • Location of mineral sites mostly located in
    developing /undeveloped countries near poor
    communities
  • Results in social environmental impacts

35
Environmental Impacts
Fig. 8
  • Extraction may remain
  • large amount of rubbish
  • on the extracted sites,
  • causing serious
  • environmental
  • pollution and
  • degradation

Fig, 9
36
Environmental impacts
Nordik Mine Site in 1995
Fig. 10
  • Water Contamination
  • Blasting digging during extraction process
    produce wastes easily get into the water as
    runoff
  • In waste disposal activities, systems direct
    waste into rivers tributaries
  • Inadequate rehabilitation of disturbed areas
    remain wastes behind the sites

Photo taken by Kira Henschel at Wisconsin mining
site at May, 1995
37
  • Nordik Mine - Drainage Downstream from Tailings
    in 1995
  • Contaminated water of mining site being pumped
    to a Lake

38
Environmental impacts cont
  • Soil disturbance
  • stripping of the overburden will loosen the soil
    cause soil erosion
  • loss of water in soil through evaporation
  • Loss of nutrient minerals in soil
  • Wet separation process in the manufacturing
    process of silica sand will wash away minerals
    and nutrients in soil, that is important for
    vegetation growth, e.g. lack of magnesium for
    plant in soil will result in chronic

39
Environment disruption resulted from mineral
extraction process
  • Mineral sand mining occurred on land has
    cleared pasture

Fig.11
www.cablesands.com.au/cswa/ company-profile.asp
40
Social Impacts from extraction process
  • Contamination of ground water for nearby
    communities
  • Runoffs from extraction sites contaminate the
    water may transport to nearby communities
  • Dinking water agricultural resources is
    polluted
  • Disease
  • Communities may get diseases through consuming
    the contaminated water / seafood
  • New diseases may be introduced to communities
    through mine workers from communities far away

41
Social Impacts from extraction process cont
  • Fodder, fuel wood and glazing communities
  • These businesses being affected due to
    environmental pollution e.g. water soil
  • Agricultural communities
  • Water for irrigation is being contaminated, loss
    of water resources for drainage
  • Plants crops die and cattle may get disease
  • Local communities and villages
  • Loss in food security for self-supply communities

42
  • Disruption of local economics system
  • Communities nearby cannot depend on their land
    for production for export and economics benefits
    e.g. case of limestone mining in Uttaranchal
  • Contamination sites requires large capital for
    rehabilitation
  • May require communities living around the
    extraction sites to pay for rehabilitation
  • Taxpayers may also need to pay for part of the
    rehabilitation program of disturbed sites

43
Transportation of natural resources for glass
manufacturing plant
  • Development of transportation systems, building
    of roads and extension of transportation network
  • Allow natural resources to transport to plants
    further away from sites than in the past
  • Places nearby trucks or railways
  • Places far away ship
  • Benefit
  • Help developing the transportation in some area
  • No significant side effects pose to the
    environment communities

44
Distribution of minerals to the locations
  • Most of the removed ore are transported away
    from their mine and distributed to their
    processing plants by trucks.

45
After discussing the effects of extraction
process for making glass, we will talk about the
Manufacturing Process of Glass
  • Glass making historical development
  • Todays glass making process
  • Impacts of glass manufacturing process

46
Development of Glass Making
  • First automated bottle machine was created in
    1905
  • Nowadays, most of the glass containers are
    manufactured by technological machines at large,
    automated factories control by computers
  • cheaper and better
  • in quality

A Float glass Plant
47
Historical Glass Manufacturing process
  • Historical method
  • heating and blowing
  • shape the glass products by hand
  • requires high skills is time consuming
  • therefore using glass is considered as luxury in
    our old world

48
Todays Glass Manufacturing Process
  • Silica sand, limestone, soda ash and cullet
    (recycled glass or broken glass) are keep dry and
    cool in a batcher house in silos or compartments
  • Mixing and weighting into proper proportion
  • Send to furnaces in hoppers
  • operated by natural gas
  • heat the mixture at 1300-1600 degrees Celsius
    into soften or molten state

Fig.12
www.glassforever.co.uk/howisglassmade/
49
  • 4. Molding --- molten glass flows to forming
    machine to mold into desire shapes
  • 5. Annealing lehrs --- reheating the glass
    in an oven
  • to ensure even cooling of glass for strengthening
    of the products
  • 6. Cooling process --- Cool for 30 min to an
    hour for safe to handle.
  • 7. Glass products are then decorated,
  • inspected again and finally packaged
  • and shipped to our customers.

glass furnace cooling systems
50
Effects from glass manufacturing process
  • Workers
  • Dangerous harmful to workers if breakage occurs
    while glass holds heated or corrosive, can result
    in serious injuries
  • Glass making process occurs at high temperature
  • Glass can broke easily under pressure, impact or
    thermal shock
  • Prevention wear protective
  • clothing and gloves to prevent
  • those injuries

51
Environmental impact
  • Environmental degradation
  • Air pollution
  • raw materials used for glass making
  • decompose at furnaces produce large
  • volume of gas such as carbon dioxide
  • combustion of gas for energy production
  • release large amount of pollutant gases, such as
    sulphur dioxide and oxides of nitrogen
  • Green house effect
  • green house gases release from the plants
    increase global temperature and can form acid
    rain

52
Environmental Impact
  • Aquatic Life
  • Hot water is released during glass making process
  • increase water temperature and dissolve oxygen in
    water
  • change aquatic habitat
  • and threaten aquatic life

53
Social Impact
  • Human Health
  • Breathing in air pollutants
  • release by the glass
  • manufacturing plant can result
  • in serious health impact
  • E.g. respiratory or lung diseases
  • Economy
  • Affect fishing and recreational businesses due to
    changes in aquatic habitat

54
Then, we will now go to the Utilization of Glass
  • History of glass
  • How is the utilization of glass importance for
    communities?
  • Global marketing and consumption status of glass
  • The impacts of glass products

55
History of Human Using Glass
  • People have used glass dating back to 5000 B.C
  • Ancient Egypt earliest use of glass, for royalty
    and priest as luxuries
  • Usually use as containers or for decoration
    purposes in human history

56
Utilization of Glass is important for Human
Development
  • Important for historical and modern
  • human development
  • Prism and lenses to study light, important to
    further induce science theories. E.g. Issac
    Newton used glass prism and lenses to explain the
    color spectrum of light in 1672
  • Magnifying glass for astronomy study, without
    glass, we are not able to observe stars and
    planets in space clearly
  • Glasses make lenses in spectacles that helped
    people to overcome sight defect
  • Main components in many new and advance
    technology devices major components of most
    modern communications systems, fiber optics
    systems, is also depend on the transmission of
    light through glass filaments

57
Different type of glass
  • practical glass
  • industrial glass
  • inspiration glass
  • glass of science and medicine

58
Examples of todays glass products
  • Containers (jars and bottles)
  •   Flat glass (windows, vehicle glazing, mirrors,
    etc.)
  •   Lighting glass (fluorescent tubes, light
    bulbs, etc.)
  •   Tableware (drinking glasses, bowls, lead
    crystal, etc.)
  •   Laboratory equipments (test tubes, cylinders,
    measuring flasks, etc.)
  •   TV tubes and screens
  •   Decorative glass
  •   Fiberglass
  •   Optical glass
  •   Vacuum flasks

59
Distribution process of glass products
  • Glass product is distributed to different
    consumers hand through trading
  • by commercial businesses
  • according to the demands of people all over the
    world

60
Consumption of Glass
  • Three largest consumers
  • glass packaging (43)
  • domestic commodities
  • construction industry

Fig. 13
National Glass Usage
http//www.bisnis.doc.gov/bisnis/country/000727gla
ss_samara.htm
61
Export Import of Glass
  • Largest Importer of past decades Europe and
    Australia
  • Today largest Importer U.S.
  • China and Indonesia has increased their import of
    glass dramatically

62
Glass Industries
  • The World Glass Industry has a gross production
    value totaling 82.3 billion

Fig. 14
www.icem.org/events/ bled/matdocen.htm
63
Glass Consumption in Europe
  • Europe is one of the large importer of glass.
    Through observing the consumption pattern of
    glass in different countries of Europe, we can
    get an image of how large is the human
    consumption of glass is

Average glass consumption in kilo/annum
1990-1995/capita in different countries
Fig. 15
waste.eionet.eu.int/activities/0000219.html
When considering the whole EU, projections
suggest that glass consumption will increase
between 24 and 53 up to the year 2010, using the
year 1995 as a base year (European Topic Centre
on Waste, 1998).
64
Consumption of glass in Europe cont
  • European Topic Center of 1998 suggested that the
    average increase in glass consumption for the EU
    and Norway during 1990 to 1996 has been increased
    by 13.6
  • It is predicted that the average increase in
    glass consumption for the EU and Norway during
    1990 to 1996 has been increased by 13.6
  • We can see that the demand of glass in our
    society never decreases and the consumption of
    glass increases every year

65
Impacts result in consumption process of glass
  • Characteristics of glass
  • Non-biodegradable (remains in our environment and
    do not decompose easily by itself )
  • Durable long lasting
  • Therefore, do not have significant environmental
    social impact during consuming process
  • But could result in serious impact after disposal

66
Fig. 16
waste.eionet.eu.int/activities/0000219.html
  • While recycling has increased by almost 50 from
    5 million to 7,4 million tonnes per year, the
    amount of waste glass for disposal has only
    decreased by 12 (6,7 million to 5,9 million
    tones) due to the simultaneous increase in waste
    glass.

67
Finally, we will discuss the Disposal of Glass
68
Glass Waste
  • Most of glass waste is generated from glass
    packaging
  • Glass waste generated from packing is among the
    top forth in the world.

Fig. 17
Waste (mPEMwdk2000 per kg of packaging
http//www.mst.dk/project/NyViden/2000/08030000.ht
m
69
How is glass waste treated?
  • Landfill
  • Recycle
  • Vitrification

70
Landfill
  • If people dump useless glass
  • into the garbage and mix it with
  • other rubbish, it will be treated as regular
    waste
  • Regular waste will then dump into waste dumping
    site or use for landfill
  • Glass waste will finally break down and decay
    into sand form naturally under erosion or
    weathering and once again return to our
    ecosystem.

71
Effects result from landfill
  • Environmental impact
  • Raise of sea level
  • drown lowland areas
  • Leachate
  • Landfill gas formation

72
Example Landfill at Seoul
  • The Sudokwon landfill site at Seoul (S. Korea)
    covers 20,749,000 square meters

Construction of the Sudokwon Landfill at Seoul
Large area of sea is filled by land
Fig. 18
smg.metro.seoul.kr9000/ waste/part4.html
73
Statistic of Sudokwon landfill
  • Leachate
  • 2,697m3/day(before soil covering)
  • 866m3/day(after soil covering)
  • Landfill gas
  • 167m3/minute (in 2001)

Fig. 19
smg.metro.seoul.kr9000/ waste/part4.html
74
Social impact from Landfill of glass waste
  • Huge amount of glass waste produce by human
    increases the need of land to get rid of the
  • use up precious landfill space, decreasing
    possible areas that can be used for landfills of
    other waste, increasing the need to establish new
    expensive landfills
  • Leachates gas releases from the landfill site
    degrade communities living condition harmful
    to human health.
  • Taxpayers are responsible for the final costs of
    landfill
  • Seoul City invested 37.3 billion and central
    government 15 billion in their landfill project.
  • Migration of population from lowland areas due to
    raise of sea level

75
Recycling of Glass
  • Recycle of glass is mostly used for packaging
  • Recycle process

76
Myths of Recycling Glass
  • Refillable bottles require more energy to make as
    they are about 50 heavier than non-refillable
    bottles to prevent breakage, and to transport
    them over long distances to sparsely located
    processing facilities. Since the raw materials of
    glass are abundant and cheap, recycling glass
    only consumes and wastes the more valuable
    non-renewable fossil fuels (Warmer Bulletin
    November, 1993)
  • It takes more energy to collect and recycle glass
    into another bottle than to make one from raw
    materials. However, the energy requirement to
    produce a refillable bottle will decrease with
    the number of returnable trips, and an eight-trip
    bottle can reduce the energy requirement by about
    two-thirds compared to a non-returnable bottle
    (Porteous, 1977)

77
Effects of recycling glass
  • Environmental impact
  • release from the recycling plant
  • Air pollution air pollutants may
  • Social impact
  • location of most recycling plants are built
    within low-income neighborhoods because of cheap
    labor and less strict regulation
  • Health impact may affect respiratory system if
    breath in pollutants
  • Case Local residents at Mercedes Arumbula
    claimed that the neighborhood and kids have
    developed asthma once the plant was built in
    their community

78
Virtification
  • Definition a new technology has been discovered
    to use recycle glass for radioactive waste
    management
  • Process
  • melt glass together with radioactive waste in
    barrels or some other container
  • glass will then bind up with radioactive
    contamination into a huge glass block
  • radioactive waste is bond by the glass and become
    immobilized
  • keep radioactive waste from interacting with
    water, stop spreading the waste

Fig. 20
www.vitrification.com/ vitrification.htm
79
Good Bad of Virtification
Volume percent of vitrified product compared to
the original waste volume
  • Benefit of virtication
  • Prevent radioactive waste pollution
  • Minimize the amount of glass waste
  • produced
  • Increase the efficiency of glass use (to
    stabilize hazardous waste)
  • High volume reduction of waste
  • Landfill space can be saved

Fig. 21
www.vitrification.com/ vitrification.htm
80
  • Negative impacts of vitrification
  • virtrified glass will finally decay after years
    and radioactive materials will have chance to get
    into our environment and cause serious problem
  • High cost
  • vitrification costs may range from 80 to 165
    per ton of soil processed for a facility
    processing 100 tons per day.

81
So, why is the life cycle of glass important for
environmental justice?
82
Environmental Justice
  • Through studying life cycle of glass can help to
    raise the social awareness of the importance of
    environmental justice
  • Social Environmental impact result from
  • Extraction of raw material for glass
    manufacturing
  • Glass manufacturing process
  • Glass consumption process
  • Disposal of glass waste
  • How are communities affected by these impacts?
  • Why are this happening?
  • How are they being affected?
  • Who are being affected?
  • Disproportional distribution between marginalize
    population in our society
  • Color, race social class
  • What is our priority?
  • Our good life terrible situation experienced by
    disadvantage communities

83
Disproportional distribution between marginalize
population
  • Why are there disproportional distribution?
  • environmental and social decisions are based on
    unequal consideration among communities that
    result in certain communities experiencing more
    serious environmental and social problems
  • How are communities being affected?
  • Different communities may experience
    disproportional distribution of consumption
    pattern, environmental pollution and inequalities
    legistration

84
Who are making benefit?
  • Most of the glass consumers are the middle or
    high class of the society
  • Big money enterprises such as industries, large
    corporations and government are gaining economics
    benefit through trading of glass

85
Who are facing the problem?
  • Most of the people living at the affected
    communities are less educated and always alienate
    from political power because of their own
    abilities (such as language or dont know where
    to appeal for it), and also some social and
    economic reasons
  • Communities usually experience less strict
    legislations and sometimes may experience unequal
    legal
  • More likely locate near colored races
    low-income class, far less to be seen in rich or
    highly educated communities

86
How to address the problem?
  • Big money enterprises and power authorities
  • Incorporate environmental justice into
    decision-making process
  • Correct the attitudes of the big money
    enterprises and power authorities
  • Every community has the right to enjoy and live
    in a safe and enjoyable environment
  • Should respect the human right of disadvantage
    communities, should not gain advantages over the
    weak ones
  • Encourage forces help the disadvantage
    communities to solve and minimize the social and
    environmental problems

87
How to address the problem cont
  • Government
  • legal legislations are needed to protect the weak
    ones
  • Legislation should be made fairly that all race,
    class and communities are considered at the same
    level in the legislation under the principle of
    environmental justice in order to protect the
    right of every race and community
  • Develop infrastructure to ensure community can
    have safe place for the increasing colonial
    activity
  • E.g. Infrastructure that have sufficient drainage
    sanitary system
  • Consumers
  • Control their materialistic desire be more
    considerate for other communities who are facing
    the problems, think in a more globally way
  • Cut down unnecessary consumption
  • save raw materials and lands for future next
    generations, decrease environmental pollution and
    social impact

88
Global Change
  • The whole world need to be changed !
  • Cost benefit analysis need to be replaced by
    cultural precautionary principle
  • Shift in the way that we make decisions (e.g.
    when deciding where to place the waste site)
  • Take every communities into consideration when
    making decisions
  • Consider if the situation is safe for every
    community in decision-making process
  • Change in the way that individual consider as
    good life
  • Colonialism is unacceptable
  • Consider good life globally, but not individual
    good life

89
References
  • Bolen, W. P. (1997, February). Sand and Gravel.
    U.S. Geological Survey. Mineral Commodity
    Summaries. Retrieved 05/19/2003, from
    http//minerals.er.usgs.gov/minerals/pubs/commodit
    y/silica/780397.pdf
  • ANSAC. (2002).California Soda Ash Deposits.
    Retrieved 05/19/2003, from www.ansac.com/100_our_s
    tory/ 103_supply.asp
  • Philips, T. Bishopwebworks. Retrieved 05/19/2003,
    from
  • science.nasa.gov/newhome/headlines/
    lms/owenslake.htm
  • Keith, John. Mineral Resource in Dessert.
    10/29/97. Retrieved 05/19/2003, from
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