1. Lecture 6 : Industrial Nonmetallic Mineral Deposits ASBESTOS MINERALS
A short series of lectures prepared for the Third Level of Special Geology, Tanta University
(GE3115) by
Hassan Z. Harraz

2. Objectives: Define what is asbestos Describe where asbestos is found
Type of Asbestos Deposits
Typical Asbestos Types in Structures
A) Serpentine Asbestos (or Chrysotile Asbestos)
B) Amphibole Asbestos :
Resources Type of Asbestos
OSHA’s Asbestos Standard
Most Common Types of Asbestos
Asbestos Fibrous Minerals
Properties of Asbestos Fibres
ASBESTOS DEPOSITSIN EGYPT
Types Of Asbestos Deposits
Asbestos Grades
THE MANUFACTURING PROCESS OF ASBESTOS
Mining of Asbestos
Separating of Asbestos
Quality Control
USES OF ASBESTOS
APPLICATION OF ASBESTOS
Properties Of Asbestos Cement Products
Applications Of Asbestos Fibres
World Asbestos Production
World Asbestos Production by Type
Global Asbestos Consumption
Health Concerns
Asbestos Diseases
Asbestos Exposure and Translocation of fiber in the human body
Asbestos Fiber Facts
Cancer Hazard and Role of Fiber Glass
Asbestos – People At Risk?
How to Avoid Asbestos Exposure
The Future
Copyright ã1999 Business & Legal Reports, Inc.

3. Asbestos Deposits

4. Asbestos History
Many people believed asbestos a "miracle" product of the 20th century…. That couldn't be further from the truth.
1st Century AD   Pliny the Elder notes that slaves working in asbestos mines die young of lung disease.
The Greeks recognized that not everything about asbestos was good.
Greek and Roman scientists recognized asbestos caused "sickness of the lungs" in the slaves that wove asbestos into cloth or mined the mineral.
Egyptian mummy’s were wrapped in asbestos containing fabric
Asbestos is a naturally occurring mineral, individuals have used it for centuries, quickly recognizing its insulating and heat-resistant properties and using them to their advantage.
1918   The Prudential Insurance Company in New York refuses to sell personal life insurance to asbestos workers .
1929   Leeds Coroner calls for public enquiry after death of Turner and Newall employee. Barking Council sends deputation to Whitehall about an asbestos factory based within its borough.
1930   Merewether and Price, medical and engineering inspectors of factories, place before Parliament a report confirming the epidemic of asbestos disease among British asbestos workers.
1931   The Asbestos Industry Regulations established. These set a "safe" level that allowed one worker in three to get asbestosis after years exposure.
1932   Turner writes to Newall complaining of the dust exposure rules saying, "We must take a small risk by stretching the regulations to suit our own ends".
1955   Richard Doll publishes evidence that asbestos causes lung cancer, 20 years after the first reports of high levels of lung cancer in asbestos workers. Doll's paper convinces the scientists.
1960   Professor Chris Wagner produces evidence of the link between asbestos and mesothelioma among South African miners and people living near the mines.
1960   The UK adopts the American "safe" standard of 1938 based on a biased sample in North Carolina. This level allows exposures 15 times the 1969 levels. Up to papers on the hazards of asbestos had been published in the US, the UK and Canada. The 52 independent papers showed asbestos to be a dangerous source of asbestosis and lung cancer; they were largely ignored. The 11 sponsored by industry presented virtually the opposite conclusions.
1968   The British Occupational Hygiene Society offers a safety standard for white asbestos 0.2 fibres/ml. The asbestos industry conducted a single survey at Turner and Newall's Rochdale plant and came up with this level which was incorporated into the 1969 Asbestos Regulations. Later work suggests that 1 in 10 workers would contract asbestos related disease at this level.
1970   The 1969 Asbestos Regulations were introduced.
1976   The Ombudsman, Sir Alan Marre, revealed the horrors of the massacre at Hebden Bridge. 12% of employees had crippling asbestos diseases. The Government launched an enquiry, the Advisory Committee on Asbestos.
1982   Yorkshire TV's documentary Alice - a fight for Life was first shown. Richard Peto, then Reader in Cancer Studies, University of Oxford, predicts a total of about 50,000 asbestos-induced deaths in the UK in the next 30 years or so. Nancy Tait and David Gee say this is a gross underestimate but are dismissed for being unscientific.
1983   The Asbestos (Licensing) Regulations are enacted. These came into force on the 1 August They cover the most hazardous jobs such as asbestos stripping or removal.
1985   The Asbestos (Prohibition) Regulations were introduced and later amended in They prohibit the import, supply and use of amphibole asbestos, principally blue and brown, products containing them and the spraying of asbestos and installation of asbestos insulation. Blue and brown asbestos are about 5% of the total in use.
1987   The Control of Asbestos at Work Regulations are introduced and later amended in 1992.
1995   The HSE sharply revises upwards its estimates of asbestos-related deaths in the period and starts an awareness campaign amongst maintenance workers.

5. Asbestos – what is it?
The word "asbestos" comes from the Greek meaning "inextinguishable."
Asbestos is a commercial term: Any fibrous mineral utilized in an industrial process with a 3:1 length to width.
 “A commercial term applied to a group of highly fibrous silicate minerals that readily separate into long, thin, strong fibers of sufficient flexibility to be woven.”
A collective mineralogic term that describes a variety of certain silicates belonging to the serpentine and amphibole mineral groups, which have crystallized in the asbestiform habit causing them to be easily separated into long, thin, flexible, strong fibers when crushed or processed.
Asbestos is a mineral fiber. It can be positively identified only with a special type of microscope. There are several types of asbestos fibers. In the past, asbestos was added to a variety of products to strengthen them and to provide heat insulation and fire resistance. 5

6. Asbestos – what is it?
Naturally occurring mineral, mined all over the world
Long silky fibers
Its heat resistance, tensile strength and insulating properties:
Resistant to abrasion
Resistant to breakdown by acid and alkali
Stable at high temperatures
A highly heat- resistant fibrous silicate mineral that can be woven into fabrics, and is used in brake linings and in fire-resistance and insulating materials.
Very high tensile strength

7. ALL asbestos can cause cancer and even when exposure is minimal
ALL asbestos can cause cancer and even when exposure is minimal. This has been demonstrated by the fact that those who live near asbestos mines have a much higher incidence of mesothelioma than the general public.

8. Photo: Getty
Raw asbestos in a disused asbestos factory in Caligny, northwestern France.

9. Type of Asbestos Deposits
There are two main types of asbestos minerals:
A) Serpentine asbestos (or Chrysotile Asbestos)
B) Amphibole asbestos.
The different types of asbestos minerals are:
Serpentine group
(93% of commercial use)
Amphibole group
(7% of commercial use)
Chrysotile (White asbestos)
Amosite (Brown asbestos)- Grunerite
Crocidolite (Blue asbestos) - Riebeckite
Anthophyllite
Tremolite
Actinolite
Of these six, three are used more commonly. Chrysotile is the most common, but it is not unusual to encounter Amosite, or Crocidolite as well. In many instances a single product will have a mixture of different asbestos types.
All types of asbestos can break into very tiny fibers. These individual fibers can be broken down so small that they can only be identified using an electron microscope. Some individual fibers may be up to 700 times smaller than the diameter of a human hair. Because asbestos fibers are so small, once released into the air, they may stay suspended there for hours or even days.
Asbestos fibers are also virtually indestructible. They are resistant to chemicals and heat, and they are very stable in the environment. They do not evaporate into air or dissolve in water, and they are not broken down over time. Asbestos is probably the best insulator known to man. Because asbestos has so many useful properties, it has been used in over 3,000 different products.
Usually asbestos is mixed with other materials to form the products. Floor tiles, for example, may contain only a small percentage of asbestos. Depending on what the product is, the amount of asbestos in asbestos containing materials (ACM) may vary from less than 1% to 100%. 9

10. Typical Asbestos Types in Structures
There are six different types of this type of mineral that have been identified and they have been divided into two groups below.
Serpentine Asbestos
Amphibole Asbestos
This asbestos has a structure that is layered with curly fibers. It is called Chrysotile and it is the only type in this category. This type was used most often in buildings in the U.S. and throughout the world because of its fireproof and heat-resistant qualities.
These asbestos fibers are like long chains that are straight and sharp and very easily inhaled. This category consists of the remaining five asbestos minerals: amosite, anthophyllite, crocidolite, and actinolite. Both amosite and crocidolite were used in many products until the 1980’s, with amosite likely to be the second most type found in buildings.
Asbestos is categorized by color however, tremolite, anthophylite and actinolite are not classified at all. White asbestos is chrysotile, Brown is amosite, and blue is crocidolite.
One common factor in all six types of asbestos is that the mineral is odorless and tasteless. If asbestos is in a product it cannot be detected be looking at it. It must be tested in a laboratory.

11. Serpentine Asbestos Amphibole Asbestos
Serpentine Asbestos
Amphibole Asbestos
Commercial Use (%)
Serpentine
(93% of commercial use)
Amphibole
(7% of commercial use)
Structure of Asbestos Fibers
Crystalline structure – sheet silicate
‘Scroll-like’ structure
Fibers are less straight, more flexible and less liable to split into finer fibers compared to the amphiboles
Crystalline structure – chain silicate
Different amphiboles distinguished by variations in chemical composition.
Fibers are generally straighter, more brittle and split into finer fibers more readily than serpentine
Asbestiform Variety
Chrysotile
Crocidolite; Amosite
Nonasbestiform Variety 
Antigorite
Riebeckite; Cummingtonite - Grunerite
Asbestos Minerals
Chrysotile - White asbestos
Amosite - Brown asbestos (Grunerite)
Crocidolite - Blue asbestos (Riebeckite)
Anthophyllite
Tremolite
Actinolite

12. A) Serpentine Asbestos (or Chrysotile Asbestos):
Chrysotile (Mg6Si4O10(OH)8) asbestos occurs in serpentine that has been altered from ultramafic igneous rocks, such as peridotite or dunite or magnesian limestones or dolomite;
In the ultramafic occurrences, the fiber in lens like veinlets enclosed in serpentine and has three modes of occurrence:
i) Cross-fiber, with fibers normal to walls, their length begin the width of the veinlet, or less if they contain “partings";
ii) Slipper, parallel or oblique to the walls, and long but of poor quality;
iii) Mass-fiber, composed of a mass aggregate of interlaced, unoriented, or radiating fibers.
Chrysotile fibers range up to 10 to 12 cm in length, rarely 20 cm; most of them are less than 2 cm.
Chrysotile
may make up from 2 to 20 %t of the rock.
Its fibers are curly and longer than other asbestos types
yields ~93 % of the world's asbestos supply.
~90% of asbestos mined (the most common asbestos mineral).
95% of all asbestos in use
its tubular serpentine rather than ribbon-like amphibole structure
Origin of Chrysotile Asbestos
Chrysotile asbestos is confined entirely to serpentine and strictly speaking, is a fibrous variety of serpentine.
Serpentinization is an autometamorphic process, and in the ultrabasic rocks, such as dunite, serpentinization has proceeded along fractures.

13. Chrysotile Asbestos: Products: Gasket Cement Insulation
yields ~93 % of the world's asbestos supply.
~90% of asbestos mined (the most common asbestos mineral).
It was the most widely used: ~90-95% of all asbestos in use
A short fiber chrysotile deposit , California –USA, considered to be the largest single mineral ore body in the world.
The most common type of asbestos and the only kind that is still mined, chrysotile was the most widely used in the world’s developed countries.
it accounts for the most health problems, though the companies that mine it continue to attest to its safety.
Chrysotile is most often used in fireproofing and in insulation products
It can be woven into cloth and was once used in theater curtains and – ironically – to make protective clothing for those who worked with high temperature equipment or liquids.
It was an ingredient in cement and was helpful in the manufacture of friction products because of its heat-resistant properties.
These included brake shoes, clutches, and disk pads. Its most recent uses were in the nuclear energy industry.
Products:
Gasket
Cement
Insulation
Roofing material

14. Chrysotile Asbestos:

15. B) Amphibole Asbestos :
The amphiboles comprise the minerals: amosite, crocidolite, termolite, actinolite and anthophyllite.
The amphibole varieties, of which crocidolite and amosite are the most important.
The crocidolite deposits are said to be the most extensive asbestos deposits in the world.
Anthophyllite
[Mg2Mg5]Si8O22(OH)2
Crocidolite = Riebeckite
Na2[(Fe, Mg)3Fe3+2] Si8O22(OH)2
Amosite = Grunerite
[Fe2Fe2+5]Si8O22(OH)2
Actinolite
Ca2(Mg Fe )Si8O22(OH)2 
Tremolite
Ca2Mg5Si8O22(OH)2

16. Amosite:
Amosite asbestos is primarily sourced in South Africa.
It often appears brown in color and its fibers are shorter and straighter than chrysotile fibers.
The commercial production of amosite, or “brown” asbestos, ended within the last decade and this type of asbestos is no longer mined.
It was at one time, however, the second-most commonly used form of asbestos and, as a result, many individuals were exposed to it during its peak use.
Amosite was employed as insulation in factories and buildings, as well as both an acoustical and anti-condensation material.
Its use has been banned in most countries for approximately the last 30 years
Products:
Cement sheets
Thermal Insulation
Roofing Products

17. Crocidilite Asbestos:
This form of asbestos was used less commonly than other types of asbestos because it isn't as resistant to heat.
Commonly called blue asbestos.
It is considered the most harmful type of asbestos
make up 3.5 % of the world's asbestos market.
Crocidolite asbestos accounted for about four percent of all asbestos once used in the United States.
This “blue” asbestos is harder and more brittle than other types of the mineral and can break easily, releasing dangerous needle-like fibers that are easily inhaled.
Crocidolite, without a doubt, is the most lethal form of asbestos. It was often used in making yarns and rope lagging, and as a reinforcement material for plastics. Crocidolite was generally mined in Western Australia, Bolivia, and South Africa.
The percentage of miners who developed asbestos cancer due to crocidolite exposure stands at a staggering 18 percent. The town of Wittenoom, Australia (population 20,000), where blue asbestos was mined for many years, had more than 1,000 people die of mesothelioma with officials estimating that another 1,000 will eventually perish from asbestos-related diseases. The town is now a ghost town, with only eight residents remaining, and has literally been erased from the map.
Products:
Ceiling tile
Fire protection
Insulation boards

18. Anthophyllite Asbestos:
Deposits are less common than other asbestos deposits.
Less of this mineral was used when compared to other forms of asbestos.
Anthophyllite asbestos, also known as “brown” asbestos is composed predominantly of iron and magnesium.
The fibers are known to be long and flexible.
Of the amphibole asbestos sub-classification, brown asbestos can be found in many talc mines and has been associated different respiratory disorders, though is not conclusively associated with mesothelioma as other varieties of asbestos are.

19. Tremolite Asbestos: Products: Paints Sealants Insulation
Termolite is an amphibole.
Termolite fibers have been useful for commercial products.
They are strong, flexible, heat-resistant, and can be spun and woven into cloth.
As an amphibole variety of asbestos fiber, tremolite asbestos is indeed associated with the development of mesothelioma and other asbestos-related cancer.
Like other varieties of asbestos, tremolite asbestos is composed predominantly of magnesium and can range from off-white to a dark green in color.
Tremolite asbestos is particularly common in vermiculite and vermiculite deposits.
Products:
Paints
Sealants
Insulation
Roofing materials

20. Actinolite Asbestos :
This mineral has straight-shaped fibers and is normally dark in color.
Actinolite was commonly combined with vermiculite to make insulation. It was also used in construction materials such as drywall and paint.
Products:
Insulation Material
Gardening
Concrete materials used in construction
Structural fire-proofing

21. Resources Type of Asbestos

22. OSHA’s Asbestos Standard
Each of these six minerals included in OSHA’s asbestos standard occurs in both an Asbestiform and a Nonasbestiform variety.
Three of the six minerals have been given a different name for each of their two forms. Chrysotile is the Asbestiform variety of the serpentine minerals group. In this group Antigorite is a common Nonasbestiform mineral. In the amphibole group, Crocidolite is the asbestiform variety of Riebeckite; Amosite is the asbestiform variety of “Cummingtonite”-Grunerite.
Asbestiform Variety
Nonasbestiform Variety
Chrysotile
Antigorite
Crocidolite
Riebeckite
Amosite
Cummingtonite - Grunerite
Wide range of useful properties have led to it being used in many products since ancient times;
Asbestiform Variety is the most common types of asbestos used in manufacturing, While Nonasbestiform Variety is Rarely used. 22

23. Nonasbestiform Asbestiform Amosite
Asbestiform and Nonasbestiform Varieties
Nonasbestiform
Asbestiform
Chrysotile
Antigorite
Crocidolite
Riebeckite
Amosite

24. Most Common Types of Asbestos
These types of asbestos are often categorized by their color, although tremolite, anthophyllite, and actinolite remain unclassified.
White – chrysotile
Brown – amosite
Blue – crocidolite
Brown asbestos
White asbestos
Blue asbestos

25. Asbestos Fibrous Minerals
The term "asbestos" refers to six fibrous minerals that have been commercially exploited and occur naturally in the environment. The U.S. Bureau of Mines has named more than 100 mineral fibers as "asbestos-like" fibers, yet only six are recognized regulated by the U.S. government. This is largely due to influential lobbying by the asbestos and stone industries, which powerfully shaped how the public perceives asbestiform minerals.
The six minerals recognized by the government include, tremolite asbestos, actinolite asbestos, anthophyllite asbestos, chrysotile asbestos, amosite asbestos, and crocidolite asbestos. Each of these minerals is categorized into two groups, serpentine and amphibole. Chrysotile asbestos is the only member of the serpentine group and the others belong to the amphibole group. The difference between these two groups is characterized by the physical components of the asbestos fibers. The serpentine group is made up of minerals that have a layered form and curly fibers and the latter group contains minerals that have straight fibers with a chain-like structure.

26. B) Crocidolite C) Amosite D) Tremolite A) Chrysotile
Ref: SEM Images: Kusiorowski, R., Zaremba, T., Piotrowski, J., & Adamek, J. (2012). Thermal decomposition of different types of asbestos. Journal of thermal analysis and calorimetry, 109(2),

27. Properties of Asbestos Fibres
Industrial applications of asbestos take advantage of a combination of properties:
Occur as bundles of fibres
Easily separated
Can split into thinner fibres
Use of fibre as reinforcing material largely dependent on length of fibre.
High length / diameter (aspect) ratios
Minimum of 20 – can be up to 1000
Combustibility
Asbestos fibres do not burn, although will undergo changes at high temperatures
Widespread use as fire-proofing
Thermal conductivity
Resistance to heat (i.e., heat-resistant fibers)
All asbestos types have very low thermal conductivities – i.e. they are all very good insulating materials
Widespread use in thermal insulation and lagging
Other properties that make asbestos useful include:
Flexibility…Sufficiently flexible to be spun
High tensile strength
lower refractive index
greater surface area and positive surface charge
Low electrical conductivity
Resistance to chemical attack (i.e., greater susceptibility to decomposition by strong acids).

28. MINERAL DEPOSITS ASSOCIATED WITH MAFIC-ULTRAMAFIC ASSEMBLAGES
ASBESTOS DEPOSITSIN EGYPT
MINERAL DEPOSITS ASSOCIATED WITH MAFIC-ULTRAMAFIC ASSEMBLAGES
1) In Ophiolite Sequence a) b)
c) Asbestos, vermiculite, corundum, talc, and magnesite deposits
2) In Layered Mafic-ultramafic Intrusions
(after Hussein ,1990)

30. Types Of Asbestos Deposits
Two types of asbestos are known in Eastern Desert namely:-
i) Chrysotite asbestos is known to occur as very small veinlets (<2 m in width) and uneconomic, crossing the serpentinitized parts of the ultramafic masses almost wherever they crop out.
ii) Anthophyllite asbestos occurs in associations with vermiculite in a number of occurrences spread over an area of ~15 km2 between 24° 28/ to 24° 29/N and 34° 27/ to 34° 47/E at Hafafit area. The main occurrences are those of
Wadi Shidani
El Duwaig
Um Graf
Um Kuhl
Um Fahm
Um kisbash
Wadi El Hisa
North Bir Hafafit
Facts: Asbestos (tremolite)- containing Vermiculite

31. Asbestos Grades
Asbestos ore is typically processed in highly automated operations designed to minimize worker exposure to mineral dust.
The ore is crushed, dried, screened, milled, and air separated to produce a variety of grades.
The two major world producers, the former Soviet Union and Canada, designate several major grades of asbestos, with further subdivisions within each grade.
Grades are based on fiber length, strength, color, and purity, plus intended application.
The following grades are based on Canadian standards:
Spinning fiber: The cleanest and longest fibers, to >12mm, are reserved for producing woven asbestos textiles.
Asbestos cement fiber: This is the longest fiber grade that is <12mm.
Paper/shingle fiber: This is essentially <5 mm (-4 mesh) fiber, with shingle fiber being generally shorter than paper fiber.
Shorts/floats: These are the shortest fibers, with most shorts or all floats <2mm (-10 mesh).
Crudes: This is crushed ore containing staple fibers >10mm. Crudes are sold to customers who process them into fibers for their own purposes.

32. THE MANUFACTURING PROCESS
Asbestos deposits are found underground, and the ore is brought to the surface for processing using conventional mining practices. Chrysotile asbestos is usually found near the surface and can be accessed with an open-pit mine. Other asbestos deposits are found at varying depths and may require tunnels as deep as 900 ft (300 m) to gain access.
Asbestos fibers are formed by the gradual growth of mineral crystals in cracks, or veins, found in soft rock formations. The crystals grow across the vein, and the width of the vein determines the resulting asbestos fiber length. Because the minerals come from the surrounding rock, the chemical composition of the fibers is similar to the rock. As a result the asbestos must be separated from the rocky ore using physical methods, rather than the chemical methods sometimes used to process other ores.
Here are the steps used to process the chrysotile asbestos ore commonly found in Canada:

33. A) Mining of Asbestos
Chrysoltile asbestos deposits are usually located using a magnetic sensor called a magnometer.
This method relies on the fact that the magnetic mineral magnetite is often found near asbestos formations.
Core drillings are used to pinpoint the location of the deposits and to determine the size and purity of the asbestos.
Most chrysotile asbestos mining operations are conducted in an open-pit mine.
A spiraling series of flat terraces, or benches, are cut into the sloping interior sides of the pit.
These are used both as a work platform and as a roadway for hauling the ore up and out of the pit. The asbestos ore deposits are loosened from the surrounding rock by careful drilling and blasting with explosives. The resulting rocky debris is loaded into large rubber-tired haul trucks and brought out of the mine. Some operations use an excavation technique called block caving, in which a section of the ore deposit is under-cut until it crumbles under its own weight and slides down a chute into the waiting haul trucks.

34. B) Separating of Asbestos
The ore contains only about 10% asbestos, which must be carefully separated from the rock to avoid fracturing the very thin fibers. The most common method of separation is called dry milling. In this method, the primary separation is done in a series of crushing and vacuum aspirating operations in which the asbestos fibers are literally sucked out of the ore. This is followed by a series of secondary separation operations to remove rock dust and other small debris.
The ore is fed into a jaw crusher, which squeezes the ore to break it up into pieces that are 0.75 in (20.0 mm) in diameter or less. The crushed ore is then dried to remove any moisture that may be present.
The ore falls on the surface of a vibrating 30-mesh screen, which has openings that are in (0.06 mm) in diameter. As the screen vibrates, the loosened asbestos fibers rise to the top of the crushed ore and are vacuumed off. Because the crushed ore is much denser than the fibers, only the very smallest rock particles get vacuumed off with the asbestos.
The very fine silt and rock particles that fall through the vibrating screen are called throughs or tailings and are discarded. The crushed ore pieces that remain on the screen are called overs and are moved to the next stage of processing.
The crushed ore from the first screen is fed through a second crusher, which reduces the ore pieces to about 0.25 in (6.0 mm) in diameter or less. The ore then falls on another vibrating 30-mesh screen and repeats the process described in steps 3 and 4.
The process of crushing and vacuum aspiration of the asbestos fibers is repeated twice more. Each time the pieces of ore get smaller until the last asbestos fibers are captured and the remaining ore is so small that it falls through the screen and is discarded. This four-step process also separates the asbestos fibers by length. The longest fibers are broken free from the surrounding rock in the first crusher and are vacuumed off the first screen. Shorter length fibers are broken free and captured on each successive set of crushers and screens, until the shortest fibers are captured on the last screen.
The asbestos fibers and other material captured from each screen are carried suspended in a stream of air and run through four separate cyclone separators. The heavier debris and rock dust particles fall to the center of the whirling air stream and drop out the bottom of the separators.
The air then passes through four separate sets of filters, which capture the different length asbestos fibers for packaging.

35. استخلاص ألياف الأسبستوس من الصخر بالتصويل الهوائى.

36. Quality Control
Asbestos fibers are graded according to several factors. One of the most important factors is their length, since this determines the applications where they may be used and, therefore, their commercial value.
The most common grading system for chrysotile asbestos fibers is called the Quebec Standard dry classification method. This standard defines nine grades of fibers from Grade 1, which is the longest, to Grade 9, which is the shortest. At the upper end of the scale, Grades 1 through 3 are called long fibers and range from 0.74 in (19.0 mm) and longer down to 0.25 in (6.0 mm) in length. Grades 4 through 6 are called medium fibers, while Grades 7 through 9 are called short fibers. Grade 8 and 9 fibers are under 0.12 in (3.0 mm) long and are classified by their loose density rather than their length.
Other factors for establishing the quality of asbestos fibers include tests to determine the degree of fiber separation or openness, the reinforcing capacity of the fibers in concrete, and the dust and granule content. Specific applications may require other quality control standards and tests.

37. APPLICATION OF ASBESTOS
Major asbestos applications worldwide are asbestos cement, friction products, roofing, insulation, flooring, plastics, and gaskets.
Cigarette Filters
Roggli VL, Broody AR: Imaging techniques for application to lung toxicology, In Toxicology of the lung ,New York; Raven press,1988,pp

39. Properties Of Asbestos Cement Products
Its tensile Strength surpass that of steel.
It has tremendous thermal stability, thermal and electrical resistance.
It is weather proof.
It absorbs moisture.

40. Firefighters & Asbestos
A firefighter’s job description is categorized as dangerous.  Their job demands them to put out deadly fires and sometimes even enter burning / collapsing buildings. Aside from the obvious risk of getting burned, they are also exposed to asbestos. Burning buildings fill the air around them with this poison because asbestos is found in multiple housing foundation materials.

41. USES OF ASBESTOS
Asbestos cement: In asbestos cement pipe asbestos provides good drainage and high green strength during manufacture, plus high pipe tensile strength, impact strength, heat resistance, and alkali resistance. In asbestos cement sheets it provides high flexural strength as well.
Friction products: Paper and shingle fibers are used in molded clutch plates and disk brake pads, while short and float fibers are used in brake linings.
Clutch plates are also made from open-weave asbestos cloth impregnated with resin. In all cases, asbestos is used for its durability, heat and moisture resistance, low thermal conductivity, and high strength.
Roofing: Short, float, and shingle fiber are used in asphalt shingles and roofing felts and in asphalt-based roof coatings to provide dimensional stability and flexibility, to enhance crack resistance and weatherability, and to control rheology (coatings).
Insulating products: Textiles for heat-resistant protective clothing are woven from spinning fiber, but most asbestos insulation products are in the form of paper, paperboard, millboard, and mat from paper-grade fiber.
Asbestos provides flexibility, dimensional stability, tear resistance, heat resistance, chemical resistance, moisture resistance, low thermal conductivity, and high electrical resistivity. Products include pipe wrap, thermal insulation in appliances, and electrical and heat insulation in electronics.
Flooring: Short fiber is used in vinyl tile to provide flexibility, resilience, durability, fire resistance, and dimensional stability. Short fiber is also coated with rubber latex and formed into paper used as backing for vinyl sheet flooring.
Plastics: Abrasion-free asbestos is used to thicken and reinforce thermosets, providing heat, tear, and electrical resistance, low heat deformation, high strength, and stiffness. Short and float fibers are used as fillers; mat, felt, paper and cloth are impregnated with resin to form laminates.
Gaskets: Abrasion-free asbestos cement- and paper-grade fibers are used in rubber-based gaskets and packing to provide resilience, plus resistance to heat, tear, and chemical attack. Densified latex-asbestos paper is also used to make gaskets.
Other uses: Short and float fibers are used in textured paints, drywall joint cements, caulking compounds, automotive undercoatings, and asphalt paving mixes for high traffic areas.

42. Uses of Asbestos
Asbestos can be strung into thin, strong fibers that are flexible, heat resistant, and chemically inert, thus making asbestos minerals suitable for use in fireproof fabrics, yarn, cloth, paper, paint filler, gaskets, roofing composition, reinforcing agent in rubber and plastics, brake linings, tiles, electrical and heat insulation, cement, and chemical filters.
The crystal structure and chemical composition of this mineral make its fibers very strong and resistant to heat and chemicals. Thus, asbestos is an excellent source for building materials, including ceiling and floor tiles, insulation for walls and pipes, decorative coatings, and roofing materials.
Widespread uses of asbestos include:
Thermal and acoustic insulation
Spray coating (as fire protection)
Fireproofing
Artificial fireplaces and materials
Asbestos reinforced building board
Re-enforcing concrete, tiles
Asbestos reinforced cement products
Plastic products (e.g. vinyl floor tiles)
Textiles
Brake linings
Pot holders and ironing board pads
Patching and spackling compounds
Wall and ceiling panels
Pipe and duct insulation
Building insulation
Friction materials (brake pads …etc)
Gaskets and packing materials
Roofing felts, Roofing materials. … etc

43. فيما يستخدم الأسبستوس ؟
لخواص ألياف الأسبستوس السابقة تمَّ دمجه مع مواد أخرى في الصناعات الآتية:
العوازل: مثل الأنابيب المعزولة والطوب العازل وأسمنت الأسبستوس
بناء السفن. 
وحدات الطاقة ومعامل التكرير
شركات البناء والتشييد لإنتاج مواد بناء مقاومة للحرائق وعازلة للصوت وللحرارة ومواد الترميم ومواد الأسطح. 
صناعات النسيج مثل: صناعة القفازات والبطاطين
في فرامل وتروس السيارات. 
الأسلاك الكهربائية. 
مجففات الشعر
أفران الخبزالمنزلية (toasters)

44. Applications Of Asbestos Fibres (CEC, 1977)

45. World Asbestos Production
Wide range of useful properties have led to it being used in many products since ancient times
Approximately 3.5 million metric tons of asbestos are produced annually.
Was commercially mined in many countries: Russia, China, Kazakhstan, Brazil, Canada, South Africa, Zimbabwe, USA, Italy, Australia, Cyprus …etc.
USGS

46. World Asbestos Production by Type from 1900 to 2012
(USGS).

47. Global Asbestos Consumption, 2012

48. While developing countries ignore the dangers of asbestos, millions of people remain at risk of developing deadly mesothelioma in the coming years.

50. Asbestos Consumption Declining Too Slowly
To be sure, certain uses of asbestos have been banned in the United States and others restricted. And there has been a significant downward trend in asbestos use in the United States, from the record high of 803,000 tons in In 2015, asbestos consumption in the United States was estimated at 360 tons, according to the USGS.
“This decline has occurred because asbestos substitutes, alternative materials, and new technology have displaced asbestos from traditional domestic markets,” states the January 2016 USGS mineral commodity summaries.

51. Health Effects Health Concerns
Exposure from natural and technological sources:
Fibers >5 micrometers long remain in the lower respiratory tract.
Fibers <3 micrometers can penetrate cell membranes.
In time, Mg is lost from chrysotile to form silica structures
Fe is gained around amphiboles, Mg is lost.
Fibers become coated with hemosiderin, ferritin. => O2- radicals
Health Effects
Because it is so hard to destroy asbestos fibers, the body cannot break them down or remove them once they are lodged in lung or body tissues. They remain in place where they can cause disease.
There are three primary diseases associated with asbestos exposure:
Asbestosis
Lung Cancer
Mesothelioma

52. Asbestos Diseases
Asbestosis: Fibrosis of the lung tissue associated with heavy and prolonged exposure to all types of asbestos. It leads to breathing problems and heart failure.
Pleural plaques: localized fibrous scars lining the space surrounding the lungs.
2) Mesothelioma: rare, malignant tumors of the pleural, pericardial, or peritoneal linings.
It has a strong association with crocidolite asbestos. Heavy exposure to chrysotile does not increase the risk.
It becomes significant 20 years after the 1st exposure and continues to climb in rate even after 45 years. It is usually fatal [50% of 280 such deaths per year in US & Canada are linked to asbestos].
The problem is international.
Bronchoginic carcinoma: LUNG CANCER
Increased death rate appears after 10 to 14 years from 1st exposure. Incidence peaks after 35 years. Strongly correlated with smoking. Non-smokers probably are not at risk. Associated with all types of asbestos.

53. Asbestos Exposure and Translocation of fiber in the human body
Ref : Miserocchi, G., Sancini, G., Mantegazza, F., & Chiappino, G. (2008). Translocation pathways for inhaled asbestos fibers. Environmental Health, 7(1), 1.

54.  Administrative structure relating to the collection of information on asbestos and asbestos-related diseases.

55. Asbestos Fiber Facts
All types of asbestos tend to break into very tiny fibers.
These individual fibers are so small they must be identified using a microscope.
Some fibers may be up to 700 times smaller than a human hair.
Because asbestos fibers are so small, once released into the air, they may stay suspended there for hours or even days.

56. Cancer Hazard and Role of Fiber Glass
The use of asbestos and asbestos-containing products has decreased dramatically but they continue to pose a health risk to workers and others because they are still found in numerous commercial and residential settings.
There have been more cases of Mesothelioma and cancer found in people working with Crocidolite than any other type of asbestos. However, all forms of asbestos, except Chrysotile, are of the same mineralogical family called Amphiboles. Even though there appear to be fewer incidences of disease in workers who deal only with Chrysotile, all asbestos forms are believed to carry similar risks.
Asbestos-containing material (ACM) is dangerous if the asbestos fibers can be released. Once they are floating freely in the air, asbestos fibers can be inhaled and cause disease.
Some ACM can easily be crumbled by hand pressure. This soft or loosely-bound material is called “friable” asbestos. Friable ACM is the greatest health concern because it can easily release fibers. In places where it is beginning to deteriorate, the likelihood of fiber release is even greater. Examples of friable asbestos-containing materials are sprayed-on asbestos ceiling insulation, fireproofing on structural beams and troweled-on acoustical insulation.
Hard ACM, in which asbestos fibers are firmly bound or encased, such as vinyl floor tile, does not generally create exposure problems. However, if it is sanded, ground, cut or disturbed in some way, even non-friable ACM can release fibers and present a hazard. Therefore, any material that contains asbestos has the potential to release fibers and become hazardous.

57. Asbestos – People At Risk?
Evidence of harmful effects from asbestos exposure became apparent during the 20th century
Workers initially found to be at risk
Asbestos miners
Asbestos insulation installers (laggers)
Asbestos textile workers
(Groups with very high exposure levels)
Occurrence of asbestosis documented first, followed later by increased risk of lung cancer and then mesothelioma
As use of asbestos insulating board increased – builders and construction trades exposed to high levels of asbestos

58. How to Avoid Asbestos Exposure
In order to avoid being exposed to asbestos, you must be aware of the locations it is likely to be found. If you do not know whether something is asbestos or not, assume that it is until it is verified otherwise. Remember that you cannot tell if floor or ceiling tiles contain asbestos just by looking at them.
If you do not know that a building material is
asbestos free…….DOT DISTURB IT.
Never
Drill
Break
Hammer
Damage
Cut
Move
Saw
Disturb
Copyright ã1999 Business & Legal Reports, Inc.

59. Asbestos Emergency Kit
Gloves
Protective eyewear
Disposable clothing
Booties
Garbage bags
Water bottle
Important Telephone numbers
The Mesothelioma Cancer Alliance recommends keeping an ‘Asbestos Emergency Kit’ on hand if you are a first responder or happen to live in an area where natural disasters (like hurricanes or earthquakes) are prevalent and asbestos exposure is therefore likely. You should keep the following items in your kit:
Gloves
Protective eyewear
Disposable clothing
Booties
Garbage bags (if you must remove and dispose of asbestos materials before a certified asbestos abatement technician is available, first wet all asbestos materials and then place them carefully in garbage bags. Seal the bags and mark them clearly so that people know the bags contain asbestos)
Water bottles (to wet asbestos materials before moving them)
Important telephone numbers of local asbestos abatement technicians and asbestos disposal locations (asbestos must be disposed of safely under the law in a designated asbestos landfill)
Copyright ã1999 Business & Legal Reports, Inc.

60. Note: Asbestos, once a prized building material, is now banned or restricted in Egypt and in more than 52 countries

61. The Future
Asbestos is still an important component in many products and processes, although its usage is expected to remain low in the United States. The stricter exposure regulations and improved manufacturing and handling procedures now in place are expected to eliminate health problems associated with asbestos.

62. References
Brady, George S., Henry R. Clauser, and John A. Vaccari. Materials Handbook, 14th Edition. McGraw-Hill, 1997.
Hornbostel, Caleb.Construction Materials, 2nd Edition. John Wiley and Sons, Inc., 1991.
OSHA Asbestos Web Page. Retrieved from:
Environmental Health and Safety online:
Environmental Protection Agency. Libby Site Background. Retrieved from:
U-W Madison. General Safety, Asbestos. Retrieved from:
Mesothelioma Cancer Alliance. Retrieved from:
Hessel PA et al. Asbestos, asbestosis, and lung cancer: a critical assessment of the epidemiological evidence. Thorax
Camus M et al. Nonoccupational Exposure to Chrysotile Asbestos and the Risk of Lung Cancer N Engl J Med 1998
Beckett WS. Current Concepts: Occupational Respiratory Diseases. N Engl J Med 2000
Steele JPC. Prognostic Factors for Mesothelioma. Hematol Oncol Clin N Am. 2005
West SD, Lee YCG. Management of Malignant Pleural Mesothelioma. Clin Chest Med 2006
Krug LM. An overview of the chemotherapy for mesothelioma. Hematol Oncol Clin N Am 2005
Calvert et al. Occupational silica exposure and risk of various diseases: an analysis using death certificates from 27 states of the United States. Occup Environ Med. 2003; 60(2):122-9.
Occupational, Industrial, and Environmental Toxicology. M Greenberg (ed.). Mosby, Inc 2003
Yarborough. Chrysotile as a cause of mesothelioma: An assessment based on epidemiology. Crit Rev Toxicol. 36: