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International Atomic Energy Agency IX.4.9. IX.4.9. Mining Waste Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term safety, safety assessment methods

International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Page 1: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

International Atomic Energy Agency

IX.4.9.IX.4.9.Mining WasteMining Waste

Disposal options for different waste types, safety principles and technologies for assuring long-term

safety, safety assessment methods

Page 2: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Waste streams generated during the different phases of Waste streams generated during the different phases of mining projectsmining projects

• Exploration wastes

• Mining wastes

• Milling wastes

• In situ leach (ISL) wastes

• Miscellaneous wastes

• Decommissioning wastes

Page 3: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Tailings properties: Tailings properties: Radiological componentsRadiological components

• The major portion of the radionuclides present in the ore remains in the tailings after uranium has been extracted

• Significant radionuclides are the decay series for uranium and thorium

• 226 Radium is often considered as the most important radiotoxic decay product in the decay series

• 226 Radium produces 222 radon-a radioactive inert gas, whose decay products can cause lung cancer

Page 4: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Radioactive decay series for uranium and thoriumRadioactive decay series for uranium and thorium

Page 5: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Waste streams- Waste streams- Exploration WastesExploration Wastes

• Material excavated from trenches etc

• Drilling sludge, cuttings and dust

• Core samples

• Disturbed ground, overburden materials

• Drilling fluids, mechanical scrap, grout and cement residues, general refuse

Drill rig P.Waggitt

Page 6: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Waste Streams: Waste Streams: Mining WastesMining Wastes• Solid wastes

• Waste rock and low grade ore from open pits and underground mines (including sub-economic material)

• Industrial waste

• Liquid wastes• Contaminated mine dewatering

water

• Contaminated surface water (process residues, oily wastes etc)

• Airborne emissions• Radon emissions from waste rock

and ore piles, open-pits and underground mines

• Dust emissions from mining and hauling activities

Tailings dam and waste stockpilesP.Waggitt

Page 7: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Waste Streams: Waste Streams: Milling wastesMilling wastes• Solid wastes

• Tailings

• Sludge, filter cakes and scales

• Process residues e.g. sulphur, scats

• Liquid wastes• Barren and Decant solutions

• Seepage from tailings management areas

• Leachate and runoff from waste rock, low grade ore and ore piles

• Plant washings

• Airborne emissions• Dust from screening and crushing

operations

• Toxic fumes from the mill, acid plant, calciner etc

• Yellow cake particles No.1 pit & tailings repository, Ranger Uranium Mine, Australia P.Waggitt

Page 8: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Waste Streams: In situ leaching (ISL) wastes

• Extraction plant liquid waste solutions (bleed solution, wasted barren solution, filter backwash)

• Small amount of solids in the form of sludge and salts

• Ion exchange residues

• Used filter media

• Chemical residues

• Industrial waste

Beverley ISL wellfield,

Heathgate Resources Pty Ltd

Page 9: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Waste streams: Waste streams: Miscellaneous wastesMiscellaneous wastes

• Domestic solid and liquid wastes

• Contaminated scrap material and equipment

• Hazardous substances (oils, chemicals and others)

• Laboratory wastes (solid, gaseous and liquid)

Page 10: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Waste streams: Waste streams: Decommissioning wastesDecommissioning wastes

• Decommissioning procedures generate wastes

• Scale from pipes and process vessels

• Residual liquids from mill components

• Decontamination residues, both solid and liquid

• Building materials, possibly contaminated

• Contaminated scrap metal from plant and machinery

• Process residues

• Unprocessed ore and low grade rock materials

Nabarlek Mill, Australia

P.Waggitt

Page 11: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Radiological and non-radiological properties of wastesRadiological and non-radiological properties of wastes

• Properties of tailings• The major component of wastes in terms of volume and probably

radioactivity

• Need to be managed for a long time

• Other liquid and solid wastes• May be no less important than tailings as contaminant source

• May have potential to move into wider environment relatively easily

Page 12: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Properties of TailingsProperties of Tailings

• Main properties to be considered when considering tailings management options include:

• Uranium ore grade

• Radiological components

• Acid generation potential

• Non-radiological contaminants

• Waste concentrates

Sub aerial tailings deposition in mined out pit

P.Waggitt

Page 13: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Properties of Tailings: Uranium Ore GradeProperties of Tailings: Uranium Ore Grade

• Uranium content of ore ranges from less than 0.1% to over 40%

• High grade ore is usually diluted with low grade or waste rock prior to milling to produce a constant U content for efficient process input and control

• Feed grades to the mill usually range from 0.1% to several per cent

• Tailings produced from high grade ore contain proportionally higher concentration of radionuclides per unit of product

• Low grade ore produces proportionally more tailings per unit of product

Page 14: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Tailings properties: Ore Grade versus tailings volumeTailings properties: Ore Grade versus tailings volume

Mine

Ore Grade

(%)

Uranium Production

(t)

Volume of Tailings

(t)

Uranium / Tailings

Ratio

Beaverlodge 0.21 21,236 10,100,000 475

Key Lake 1.95 71,611 4,400,000 61

McArthur River

12.75 160,200 4,400,000 27

Page 15: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Tailings properties: Tailings properties: Acid Mine DrainageAcid Mine Drainage• Caused by the oxidation and

hydrolysis of sulfide materialssuch as pyrite and pyrrhotite in the presence of moisture and oxygen

• Common problem around the world in many mines in both tailings and waste rock

• Oxidation process forms sulfuric acid, which results in:

• Elevated concentrations of toxic heavy metals and radionuclides in discharges and seepage from the tailings

• Reduction in pH of adjacent water systems

• Unacceptable environmental impacts

Acid drainage seeping from waste rock stockpile

Rum Jungle Uranium Mine, Australia. P.Waggitt

Page 16: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Tailings properties: Tailings properties: Non-radiological ContaminantsNon-radiological Contaminants

• Large number of non-radiological contaminants, mostly metals

• Contaminants in tailings depend on the ore and milling process used

• Non-radiological contaminants most commonly found in the tailings

• are listed in the next slide

• May be potential sources of contamination

• Useful as tracers in monitoring

Page 17: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Tailings properties: Tailings properties: Non-radiological Contaminants Non-radiological Contaminants (continued)(continued)

• Metallic componentsArsenic Barium Boron Cadmium Calcium Chromium

Copper Iron Lead Magnesium Manganese Mercury

Nickel Selenium Silver Vanadium Zinc

Molybdenum

• Non-MetalsAmmonium Carbonates Chlorides Cyanide

Isodecanol

Kersosene Nitrates Phosphoric acid Pyrite Pyrrhotite

Sulphates Tertiary amines Tributyl phosphate

Page 18: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Tailings properties: Tailings properties: Waste Precipitates and ConcentratesWaste Precipitates and Concentrates

• Solid wastes formed as the result of mill effluents and other contaminated waters treatment

• Examples:

• Sludge from the neutralization of acidic solutions

• Sludge from the treatment process of mill effluent with barium chloride

• Brine streams from water treatment e.g. reverse osmosis or ion exchange

• Usually stored within the tailings management areas

• May cause problems due to their poor consolidation properties and contaminant content

Page 19: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Contaminant Release from Uranium Mill tailingsContaminant Release from Uranium Mill tailings

• Most important release mechanisms

• Air emissions: radon and dust

• Seepage from tailings management areas

• Structural failure of containment structures

• Spills during the transport of tailings

• Erosion of covers

• Unauthorized disturbance or removal of tailings

Unauthorized digging in tailingsD.Reisenweaver

Page 20: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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General Exposure Pathways to HumansGeneral Exposure Pathways to Humans• Atmospheric pathways

• Inhalation of radon and its daughters

• Inhalation of radioactive particulates

• External irradiation (gamma)

• Atmospheric and terrestrial pathways

• Ingestion of contaminated foodstuffs

• External irradiation

• Aquatic pathways• Ingestion of contaminated water

• Ingestion of foods produced using irrigation, fish and other aquatic biota

• External irradiation

Sheep grazing on tailings areaD.Reisenweaver

Page 21: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Environmental transfer and Dose Model (chart) Environmental transfer and Dose Model (chart)

Page 22: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Non-Radiological ContaminantsNon-Radiological Contaminants

• Often the impacts of non-radiological contaminants is as important or even more important than radiological impacts (however radiological impacts may be more important to the public)

• Non- radiological parameters may also be necessary to understand the environmental processes driving the dispersion of radioactive contaminations (e.g. ph, ground water head, etc.)

• Non-radioactive parameters may also be used as:

• analogues for radioactive contaminants (e.g. natural lead for lead-210 where there is a direct relationship)

• tracers for contamination studies and models

Page 23: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Long Term ImpactLong Term Impact

• The radiation in uranium waste rock and tailings is extremely long lived

• Impacts cannot only be considered in the short term but must include the potential effects on future generations

• Often larger impacts occur after the closure of a facility

Wall made using tailings in the mortarD.Reisenweaver

Page 24: International Atomic Energy Agency IX.4.9. Mining Waste Disposal options for different waste types, safety principles and technologies for assuring long-term

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Institutional ControlInstitutional Control

• Radiation Protection and Safety can only be assured if there is a system in place and it is working and it is consistent

• The system has to be organized and implemented by an independent “power” to ensure it is effective

• Because the potential problems are so long lived, safety has to be organised by a body that will also be long lived

• Governments are probably the only organisations likely to be around long enough

• We call the process behind these systems Institutional Control

• Includes:

• Laws to provide a legal basis for control and penalties for breaches

• Funding to implement the process, provision of inspectors and safety guides, manuals etc

• Setting approved levels of training for operators and regulators alike

• Providing for continuous improvement in the system and interaction with other authorities, both national and local, as well as international

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SummarySummary

• Mining and milling generates a range of different wastes which have the potential to impact the public and the environment in a number of ways

• There is a range of pathways by which the operation may cause exposure and these may change over the life of the facility

• Tailings and sometimes waste rock generally have the most potential for providing significant impacts

• Non-radiological contaminants are important in their own right, but also may give information about the dispersal of the radioactive components

• Economic and social factors are an important consideration for both the operator and the regulator

• Long term impacts often are potentially more important than impacts arising during operations

• The creation of Institutional Control provides a mechanism for assurance of protection and safety in the long term