Topic 2 the mining cycle

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2015- 2016

Topic 2: The Mining Cycle

Prof. Dr. H.Z. Harraz Presentation The Mining Cycle

mailto:[email protected]

Outline of Topic 2:

We will explore all of the above in Topic 2.

WHAT IS MINING?

MINE LIFE CYCLE

LIFE CYCLE OF DEPOSITS

LIFE-CYCLE OF A MINE PROJECT

STAGES IN THE LIFE CYCLE OF A MINE PROJECT:

1) Prospecting (Mineral Deposit)

2) Exploration (Ore Body):

3D modeling software's for mining sectors

Mineral Resource

Mineral Reserve

3) Development

4) Exploitation (Mine):

MINE PLANNING CYCLE

5) Reclamation:

ENVIRONMENTAL IMPACTS OF NONRENEWABLE MINERAL RESOURCES:

SOURCES OF METAL POLLUTION

Harmful Environmental Effects of Mining

Persistent, Bio-accumulative and Toxi (PBT ):

Lead

Mercury

Cadmium

Arsenic

2Prof. Dr. H.Z. Harraz Presentation

The Mining Cycle1 February 2016

WHAT IS MINING?

Mining

The activity that removes from the earth’s crust the abnormal concentration of metal found in the deposit

Mining is extracting ore or minerals from the ground

MineAn opening or excavation of

the earth from which minerals are extracted

3Prof. Dr. H.Z. Harraz Presentation The Mining Cycle

1 February 2016

MINE LIFE CYCLE

Exploration

MiningReclamation (or Closure)

Geologists explore for useful metals by mapping, drilling, and sampling rocks and minerals

1 February 2016Prof. Dr. H.Z. Harraz Presentation

The Mining Cycle 4

LIFE CYCLE OF DEPOSITS


The Mining Cycle 5

LIFE-CYCLE OF A MINE PROJECT

1 February 2016 Prof. Dr. H.Z. Harraz Presentation The Mining Cycle

6

MINE PLANNING CYCLE

1 February 2016 Prof. Dr. H.Z. Harraz Presentation The Mining Cycle

7


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STAGES IN THE LIFE CYCLE OF A MINE PROJECT

The overall sequence of activities in modern mining is often compared with the five stages in the life of a mine:

Sequence of Activities in Mining:

Stages in the Life of a Mine:

Responsibility

1) Prospecting Stage 1 : Prospecting Geologists, Geophysics, and Mining engineers often share responsibility for these two stages-geologists more involved with the former, mining engineers more with the latter

2) Exploration (discovery)

Stage 2 : Exploration and Assessment3) Feasibility study

4) Mine development Stage 3 : Construction

Mining engineer

5) Extraction/ production

Stage 4 : Exploitation or Operation

6) Processing/ beneficiation/ milling

7) Marketing

8) Closure/post-mining use Stage 5 : Reclamation


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Prospecting and exploration, precursors to actual mining, are linked and sometimes combined. Geologists, Geophysics, and Mining engineers often share responsibility for these two stages-geologists more involved with the former, mining engineers more with the latter.

Likewise, development and exploitation are closely related stages; they are usually considered to constitute mining proper and are the main province of the Mining engineer.

Reclamation has been added to these stages since the first edition, to reflect the times. Closure and reclamation of the mine site has become a necessary part of the mine life cycle because of the demands of society for a cleaner environment and stricter laws regulating the abandonment of a mine.

The overall process of developing a mine with the future uses of the land in mind is termed sustainable development.

The fifth stage of the mine is thus of paramount importance and should be planned at the earliest possible time in the life of the mine.

The five stages in the life of a mine are summarized in Table 1.


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Table 1: Stages in the Life of a Mine (from Hartman and Matmansky, 2002; p.8).

Stage/

(Project Name) Procedure Time Cost / Unit Cost

Precursors to Mining

1) Prospecting

(Mineral deposit)

Search for ore:

a) Prospecting methods:

Direct: Physical geologic

Indirect: Geophysical, Geochemical.

b) Locate favorable loci (maps, literature, old mines)

c) Air: Aerial photography, Airborne geophysics,

Satellite

d) Surface: Ground geophysics, Geology.

e) Spot anomaly, analyze, evaluate.

1 - 3 yr

$0.2 — 10 million

or $0.05 — 1/ton

($0.05 — 1.1/tonne)

2) Exploration

(Ore body)

Defining extent and value of ore (examination /

evaluation):

a) Sample (drilling or excavation), Assay, test

b) Estimate tonnage and grade

c) Valuate deposit (Hoskold formula or discount

method):

present

value= income - cost

Feasibility study: make decision to

abandon or develop.

2 - 5 yr

$1— 15 million

or $0.20 — 1.5/ton

($0.22 — 1.65/tonne)


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Table 1: Stages in the Life of a Mine (from Hartman and Matmansky, 2002; p.8).

Stage/

(Project Name) Procedure Time Cost/Unit Cost

Mining Proper

3) Development (Prospect)

Opening up ore deposit for production:

a) Acquire mining rights (purchase or lease), if not done

in stage 2.

b) File environmental impact statement, technology,

assessment, permit.

c) Construct access roads, transport system.

d) Locate surface plant, construct facilities.

e) Excavate deposit (strip or sink shaft).

2 - 5 yr

$10 — 500 million

or $0.25 — 10/ton

($0.275 — 11/tonne)

4) Exploitation (Mine)

Large-scale production of ore:a) Factors in choice of method: geologic, geographic,

economic, environmental, societal safety

b) Types of mining methods:

Surface: open pit, open cast, etc.

Underground: room and pillar, block caving, etc.

c) Monitor costs and economic payback (3 - 10 yr)

10 - 30 yr

$5 — 75 million/yr

or $2 — 150/ton

($2.2 — 165/tonne)

Post-mining

5) Reclamation (Real

estate)

Restoration of site:

a) Removal of plant and buildings

b) Reclamation of waste and tailings dumps

c) Monitoring of discharges

1 - 10 yr

$1 — 20 million

$0.2 — 4/ton

($0.22 — 4.4/tonne)


1 February 2016

1) Prospecting (Mineral Deposit) Prospecting, the first stage in the utilization of a mineral deposit, is the search for ores or other valuable minerals (coal or nonmetallics). Because

mineral deposits may be located either at or below the surface of the earth, both direct and indirect prospecting techniques are employed.

a) The direct method of discovery, normally limited to surface deposits, consists of visual examination of either the exposure (outcrop) of the deposit or the loose fragments that have weathered away from the outcrop. Geologic studies of the entire area by: i) aerial photography, ii) geologic maps, and iii) structural assessment of an area, the geologist gathers evidence by direct methods to locate mineral deposits. Precise mapping and structural analysis plus microscopic studies of samples also enable the geologist to locate the hidden as well as surface mineralization.

b) The most valuable scientific tool employed in the indirect search for hidden mineral deposits is geophysics, the science of detecting anomalies using physical measurements of gravitational, seismic, magnetic, electrical, electromagnetic, and radiometric variables of the earth. The methods are applied from the air, using aircraft and satellites; on the surface of the earth; and beneath the earth, using methods that probe below the topography. Geochemistry, the quantitative analysis of soil, rock, and water samples, and geobotany, the analysis of plant growth patterns, can also be employed as prospecting tools.

Prospecting activity is largely conducted by geologists and geophysicists, assisted by field samplers, drillers, and laboratory personnel (for chemical assays).

How prospecting conducted and its cost can vary significantly, depending on whether a company is prospecting areas. The difference between these two types of prospecting methods:-

i) Remote sensing tools:

Aeromagnetic and Radiometric surveys

Gravity surveys

Seismic surveys

ii) Ground prospecting:

Historical data

Geological mapping

GIS (Geographic Information System)

Magnetic surveys

Sampling (soil, rock, ….. etc.)

Chemical assays

Tools for mineral prospecting: In increasing order of cost per square km, prospecting methods are:

Remote sensing (satellite imagery),

Geophysical surveys,

Geological mapping,

Geochemical surveys.

Radiometric surveys

Prof. Dr. H.Z. Harraz Presentation

2015-Where have we come from and where are we going to?

Fig.1: Application of integrated geophysical imaging across the mining lifecycle


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2) Exploration (Ore Body)The second stage in the life of a mine, exploration, determines as accurately as possible the size and value of a

mineral deposit, utilizing techniques similar to but more refined than those used in prospecting.

The line of demarcation between prospecting and exploration is not sharp; in fact, a distinction may not be possible in some cases. Exploration generally shifts to surface and subsurface locations, using a variety of measurements to obtain a more positive picture of the extent and grade of the ore body.

Exploration is commonly the longest and riskiest “stage” on the road to establishing a mine, and can take up to several years for each project.

For one successful prospect that will develop into a mine, many more will be abandoned without any further development.

Exploration activity is largely conducted by geologists and geophysicists, assisted by field samplers, drillers, and laboratory personnel (for chemical assays).

How exploration is conducted and its cost can vary significantly, depending on whether a company is exploring areas.

Ground exploration:

Geological mapping

GIS (Geographic Information System)

Drilling (RAB, RC, diamond)

Sampling (chip, rock, ….. etc.)

Chemical assays

What tools are used depends on:

whether we are exploring in any areas;

the size and accessibility of the area to be explored;

whether we are looking for deposits exposed at surface or ‘‘blind’’ deposits (i.e. deposits hidden under variably thick cover -up to several hundreds of meters);

the stage of exploration. 15Prof. Dr. H.Z. Harraz Presentation The Mining Cycle

1 February 2016

3D Modeling Software's for Mining Sectors

SurpacGEOVIA Surpac™ is the world’s most popular geology and mine planning software. It delivers efficiency and accuracy through ease-of-use, powerful 3D graphics, and workflow automation.

GEMSGEOVIA GEMS™ provides collaborative geology and mine planning capabilities that support cross-functional teams involved in exploration, modelling, mine design, long-term planning, and production scheduling.

MinexGEOVIA Minex™ provides the best geology and mine planning tools for coal and other stratified deposits, ensuring resources are evaluated accurately and mined efficiently.

WhittleGEOVIA Whittle™ is the world’s most trusted strategic mine planning software used to determine and optimise the economics of open pit mining projects.

MineSchedGEOVIA MineSched™ is the most innovative scheduling software experience for mining puts you back in the driver’s seat to maximize productivity and profits.

PCBCGEOVIA PCBC™ is used by virtually every major mining company involved in block caving who rely on its comprehensive functionality to assist with feasibility studies, design, and production management.

GEOVIA Gemcom software package.

Vulcan, the premier 3D mining

software solution in the world, allows

users to validate and transform raw

mining data into dynamic 3D models,

accurate mine designs and operating

plans from Maptek.

Leapfrog Geo, is a workflow

solution for geological modelling. It

harnesses the full power of the

Leapfrog engine, to create the time

and opportunity to reduce risk

associated with geological modelling..

Micromine, is a modular solution that allows you to capture, manage and

interpret critical mining and exploration data. As an explorer, Micromine provides

you with an in-depth understanding of your project so you can target prospective

regions more accurately, increasing the chance of your project’s success. As a

miner, Micromine gives you easy-to-use modelling, estimation, and design tools

to simplify your day-to-day design and production tasks.

Most abandoned 3D modeling software's for mining sectors:


The Mining Cycle 14

1 February 2016Prof. Dr. H.Z. Harraz Presentation The Mining Cycle 16

http://www.geovia.com/products/Surpac

http://www.geovia.com/products/GEMS

http://www.geovia.com/products/Minex

http://www.geovia.com/products/Whittle

http://www.geovia.com/products/MineSched

http://www.geovia.com/products/PCBC

http://www.geovia.com/products/Surpac

http://www.geovia.com/products/GEMS

http://www.geovia.com/products/Minex

http://www.geovia.com/products/Whittle

http://www.geovia.com/products/MineSched

http://www.geovia.com/products/PCBC

Exploration Results include results of outcrop sampling, assays of drill hole intersections, geochemical results and

geophysical survey results.

3D Geological Modeling

The 3D underground geological model for ore deposit structures interpolated

from detailed surface geological map & cross-sections derived from downhole

drilling data .

Exploration Results


The Mining Cycle 17

1 February 2016Prof. Dr. H.Z. Harraz Presentation The Mining Cycle

Mineral ResourceMineral resource estimation has changed considerably

in the past 25 years.

The fundamental key to successful mineral project is resource estimation with a clear understanding of the

resource geology and mining aspects of deposit.

Mineral Resources are sub-divided, in order of increasing geological confidence, into Inferred,

Indicated and Measured categories..

Example of Resource Estimation


The Mining Cycle18

1 February 2016Prof. Dr. H.Z. Harraz Presentation The Mining Cycle

Mineral ReserveOre Reserves are those portions of Mineral Resources that, after the application of all Modifying Factors, result in an estimated tonnage and grade.

Ore Reserves are sub-divided in order of increasing confidence into Probable Ore Reserves and Proved Ore Reserves.


The Mining Cycle 20

1 February 2016Prof. Dr. H.Z. Harraz Presentation The Mining Cycle 19

2) Exploration (Cont.)Representative samples may be subjected to chemical, metallurgical, X ray, spectrographic, or radiometric

evaluation techniques that are meant to enhance the investigator’s knowledge of the mineral deposit. Samples are obtained by chipping outcrops, trenching, tunneling, and drilling; in addition, borehole logs

may be provided to study the geologic and structural make up of the deposit. Rotary, percussion, or diamond drills can be used for exploration purposes. However, diamond drills are favored because the cores they yield provide knowledge of the geologic structure. The core is normally split along its axis; one half is analyzed, and the other half is retained intact for further geologic study.

An evaluation of the samples enables the geologist or mining engineer to calculate the tonnage and grade, or richness, of the mineral deposit. He or she estimates the mining costs, evaluates the recovery of the valuable minerals, determines the environmental costs, and assesses other foreseeable factors in an effort to reach a conclusion about the profitability of the mineral deposit. The crux of the analysis is the question of whether the property is just another mineral deposit or an ore body. For an ore deposit, the overall process is called reserve estimation, that is, the examination and valuation of the ore body. At the conclusion of this stage, the project is developed, traded to another party, or abandoned.

2.1) Resource evaluation2.2) Reserve definition2.3) Mineral determination After a prospective mineral is located, the mine geologist then determines the ore properties.

This may involve chemical analysis of the ore to determine the composition of the sample. Once the mineral properties are identified, the next step is determining the quantity of the ore.

This involves determining the extent of the deposit as well as the purity of the ore. The engineer drills additional core samples to find the limits of the deposit and calculates the

quantity of valuable material present in the deposit.

2.4) Feasibility study


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3) Development In the third stage, development, the work of opening a mineral deposit for exploitation is performed. With it begins

the actual mining of the deposit, now called the ore. Access to the deposit must be gained either:

i) by stripping the overburden, which is the soil and/or rock covering the deposit, to expose the near-surface ore for mining,

{ Stripping of the overburden will then proceed if the minerals are to be mined at the surface. Economic considerations determine the stripping ratio, the ratio of waste removed to ore recovered; it may range from as high as 38 m/tonne for coal mines to as low as 0.8 m/tonne in metal mines. Some nonmetallic mines have no overburden to remove; the mineral is simply excavated at the surface}.

or ii) by excavating openings from the surface to access more deeply buried deposits to prepare for underground

mining. In either case, certain preliminary development work, such as:

i) Acquiring water and mineral rights, ii) Buying surface lands, iii) Arranging for financing, andiv) Preparing permit applications and an environmental impact statement (EIS), will generally be required

before any development takes place. When these steps have been achieved, the provision of a number of requirements:

i) Access roads,ii) Power sources, iii) Mineral transportation systems,iv) Mineral processing facilities, v) Waste disposal areas,vi) Offices, and other support facilities-must precede actual mining in most cases.

Development for underground mining is generally more complex and expensive. It requires careful planning and layout of access openings for efficient mining, safety, and permanence. The principal openings may be shafts, slopes, or adits; each must be planned to allow passage of workers, machines, ore, waste, air, water, and utilities. Many metal mines are located along steeply dipping deposits and thus are opened from shafts, while drifts, winzes, and raises serve the production areas. Many coal and nonmetallic mines are found in nearly horizontal deposits. Their primary openings may be drifts or entries, which may be distinctly different from those of metal mines.


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4) Exploitation (Mine) Exploitation, the fourth stage of mining, is associated with the actual recovery of

minerals from the earth in quantity. Although development may continue, the emphasis in the production stage

is on production. Usually only enough development is done prior to exploitation to ensure that production, once started, can continue uninterrupted throughout the life of the mine.

The mining method selected for exploitation is determined mainly by the characteristics of the mineral deposit and the limits imposed by safety, technology, environmental concerns, and economics. Geologic conditions (e.g., such as the dip, shape, and strength of the ore and

the surrounding rock) play a key role in selecting the method. Traditional exploitation methods fall into two broad categories based on locale:

surface or underground: i) Surface mining includes mechanical excavation methods such as open pit

and open cast (strip mining), and aqueous methods such as placer and solution mining.

ii) Underground mining is usually classified in three categories of methods: unsupported, supported, and caving.


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Mine Construction & Operation

Prepare mine sites, build complete facilities, manage mine operations


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Mill Complex

Bingham Canyon Mill

Mill Control Room

مش عارف .... لو جاايب امتياز تستلم عربية موديل السنة

frown emoticonاقوول ايه


1 February 2016

5) Reclamation The final stage in the operation of most mines is reclamation, the process of closing a mine and recontouring,

revegetating, and restoring the water and land values. The best time to begin the reclamation process of a mine is before the first excavations are initiated. In other words, mine planning engineers should plan the mine so that the reclamation process is considered and the

overall cost of mining plus reclamation is minimized, not just the cost of mining itself. The new philosophy in themining industry is sustainability, that is, the meeting of economic and environmental needs of the present whileenhancing the ability of future generations to meet their own needs.

In planning for the reclamation of any given mine, there are many concerns that must be addressed.i) The first of these is the safety of the mine site, particularly if the area is open to the general public. The

removal of office buildings, processing facilities, transportation equipment, utilities, and other surfacestructures must generally be accomplished. The mining company is then required to seal all mine shafts,adits, and other openings that may present physical hazards. Any existing highwalls or other geologicstructures may require mitigation to prevent injuries or death due to geologic failures.

ii) The second major issue to be addressed during reclamation of a mine site is restoration of the land surface,the water quality, and the waste disposal areas so that long-term water pollution, soil erosion, dustgeneration, or vegetation problems do not occur. The restoration of native plants is often a very importantpart of this process, as the plants help build a stable soil structure and naturalize the area. It may benecessary to carefully place any rock or tailings with acid-producing properties in locations where rainfallhas little effect on the material and acid production is minimized. The same maybe true of certain of theheavy metals that pollute streams. Planning of the waste dumps, tailings ponds, and other disturbed areaswill help prevent pollution problems ,but remediation work may also be necessary to complete thereclamation stage of mining and satisfy the regulatory agencies.

The final concern of the mine planning engineer may be the subsequent use of the land after mining is completed.Old mine sites have been converted to wildlife refuges, shopping malls, golf courses, airports, lakes, undergroundstorage facilities, real estate developments, solid waste disposal areas, and other uses that can benefit society. Byplanning the mine for a subsequent development, mine planners can enhance the value of the mined land and helpconvert it to a use that the public will consider favorable. The successful completion of the reclamation of a mine willenhance public opinion of the mining industry and keep the mining company in the good graces of the regulatoryagencies.


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Tailing Dam Reclamation

Hydro-Seeding a Waste Dump

Revegetation


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ENVIRONMENTAL IMPACTS OF NONRENEWABLE MINERAL RESOURCES


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SOURCES OF METAL POLLUTION Mining:

Air

Water

Land

Fossil Fuel Combustion: Air

Water

Land

Other sources

Natural Sources


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Harmful Environmental Effects of Mining

1) Acid Mine Drainage (AMD)

Sulfur in ores react with water and oxygen to form sulfuric acid which leaks out from the mine

Thiobacillus ferroxidans bacteria in acid water hastens the process

Acid is carried off the mine site by rainwater or surface drainage and deposited into nearby streams, rivers, lakes and groundwater. AMD severely degrades water quality, and can kill aquatic life and make water virtually unusable.

2) Heavy Metal Contamination & Leaching

Heavy metal pollution is caused when such metals as arsenic, cobalt, copper, cadmium, lead, silver and zinc contained in excavated rock or exposed in an underground mine come in contact with water.

Metals are leached out and carried downstream as water washes over the rock surface.

leaching is particularly accelerated in the low pH conditions such as are created by Acid Mine Drainage.

3) Processing Chemicals Pollution

occurs when chemical agents (such as cyanide or sulphuric acid used by mining companies to separate the target mineral from the ore) spill, leak, or leach from the mine site into nearby water bodies. These chemicals can be highly toxic to humans and wildlife.

4) Erosion and Sedimentation

Mineral development disturbs soil and rock in the course of constructing and maintaining roads, open pits, and waste impoundments.

erosion of the exposed earth may carry substantial amounts of sediment into streams, rivers and lakes.

Excessive sediment can clog riverbeds and smother watershed vegetation, wildlife habitat and aquatic organisms.


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1) Acid Mine Drainage (AMD)

2) Heavy Metal Contamination

3) Processing chemical pollution

4) Erosion and Sedimentation

29

Metals are emitted in air during…

Particulates fall out by gravity or wash out by rain

Soil Vegetation Water

Air emissions are mostly particulates

Mining, smelting, refining, Manufacturing and Recycling


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Crushing of ores produces tailings. Traces of pollutants like mercury,

arsenic, cadmium and uranium may leach out of tailings and contaminate groundwater and landfills.

Processing chemicals (e.g., Cyanide) are major hazards (cyanide spill in Danube).

Smelting releases toxic elements, SO2 etc and causes acid rain which can destroy vegetation

Mineral Processing lead to…


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Persistent, Bio-accumulative and Toxi (PBT )

PBT = Persistent, Bio-accumulative and Toxic:

5 nutrient metals: Cu, Cr, Ni, Al, Zn.

6 non-nutrient metals: Sb, As, Be, Cd, Pb, Hg.

Metals cannot be banned and are present in nature, in soil, in food and in water.

Pb, Cd, As and Hg pose special problem.


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Lead

Present Scenario compared to 100 yrsago: 4X in Antarctica Ice 15X greater in Coral 500X greater in household dusts

Was used in Plumbing soldering Paint Gasoline Lead types for printing, Lead in printing ink

Adverse Effects of Lead Affects Nervous system of human fetus and

small children

Most of the lead is stored in bones and along with Calcium, is released in mother’s milk

Affects IQ, causes delinquency, kidney cancer

In adults: High BP, affects nervous system and kidney, anemia, infertility

Similar to other metals: mining, smelting, coal burning power plants, incinerators

Lead paints , lead contaminated soil, plumbing affects children in poorer households Made worse by poor diet low in Ca and Fe

For people living in Lead free environment: Food is the major source

Gasoline Lead level in exhausts fell 90% after banning of

lead in gasoline – the substitute, Benzene, is carcinogen

Lead in the blood of Children fell to 4 -6 microgram/lt (threshold: 10 micrograms/lt)

Major problem now in China

Incinerator: P2 measures: the following are banned:

Lead in gasoline, in paint, in printing ink, in solders in plumbing and cans, in sealing wine bottles, in toys

Imported products can still have lead Car batteries still contain lead

Sources of Lead


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Mercury Much of the mercury in the environment originates as

mercury vapor from coal burning power plants and incinerators (2-3000 tons) and from natural sources (2700 to 6000 tons).

Elemental Mercury not as injurious as methylmercury. Most of the mercury ends up in the ocean where

bacteria in the bottom sediments convert elemental mercury to methylmercury.

Methylmercury biomagnifies up the food chain Some game fish has Hg conc. 200,000 X that of surrounding

water. Can cause roblems to humans eating these fish, particularly

among children, old people and pregnant women.

95% of the exposure comes from eating contaminated fish.

Toxic to nervous system.Minamata Tragedy:

Chisso Corp discharged mercury in Minamata bay from 1930.

Biomagnification in Fish upto 40 ppm (0.5 ppm safe limit).

200,000 people were poisoned. Chronic nervous system damage, miscarriages,

deformed fetus. Settled in 1996 after 30 years of litigation.

Adverse effects of Mercury

Regulations: EPA has set standards for drinking water, air-emissions and is tackling the biggest source: coal burning power plants.Reduce workplace exposure.Reduce or eliminate mercury containing

products: In rechargeable batteries and button cells. Remove batteries from municipal solid

waste. Green Lights program: Hg free fluorescent

light. Phase out mercury from hospital and lab

products.

Reducing Risk from Mercury


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Cadmium

Discovered in 1817, heavily mined since mid-40s

Bioaccumulates in kidney – increases with age

Itai-itai disease among older women in Japan

Cancer, birth defects in ratsSources:

Mining and smelting of Zn, Pb, Cu Coal burning Phosphatic fertilizers, sewage sludge Nicad batteries: a major source in

Municipal Solid Waste

90% of the exposure (of non-smokers) is through food:

Fish, scallops and oysters Liver and kidneys of larger animals : beef,

venison Readily taken up by plants – concentrated

in Tobaccos. 90% of inhaled Cd is absorbed by the body

Control: EPA regulations: Power plants still not controlled Nicad batteries still a major problem

Metal smelting of Copper and Lead

Used to be common weed killer Emitted by volcanoes Naturally present in soil

Major environmental problem in Bangladesh

Level in seafoods higher than in land-grown food.

Much of the Arsenic in Food is not bioavailable

CCA (Chromated Copper Arsenate) used to treat wood including playground equipments – can contaminate soil

Arsenic


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Topic 2 the mining cycle

Education