Air pollution control of coal and copper mining

1. Air pollution
Control of Coal and
Copper mining
Industry
Bivin Ebenezer. S
M.E Environmental Engineering and
Management
1962003

2. Introduction
• Air emission from mining can affect not only the surrounding area, but can affect
regional and global air quality.
• Air pollutants can be roughly categorized into gaseous or particulate.
• Gaseous emissions - sulfur oxides, nitrogen oxides, carbon oxides, photochemical
oxidants, VOCs, hydrocarbons and methane.
• Particulate includes – P.M 2.5 and P.M 10
• Air pollution control measures involve planning and implementing a series of
preventive and suppressive measures in addition to dust extraction system.
• Gaseous emission originates from mining equipment’s and process such as diesel
motors and blasting. whereas methane originates from mineral deposits.
• Sources of pollution in mining is classified into
1)Mobile source – vehicles trucks, and other excavation equipment
2)Stationary -drying, roasting and smelting
3)Fugitive – fugitive dust, materials handling and storage, blasting that cannot
be passed through a vent, stack or chimney system to reduce emission.

3. Methane:
• Methane which is the primary component of natural gas is produced and is stored in
the internal surfaces of the coal.
• It is released as a by-product at great volume during the cola mining operation.
• In the case of copper mining, the deposits are located near methane containing
deposits such as cola or carbonaceous shales Or can migrate in gaseous forms
through joints, faults, or dissolved in water and get transported.
• It poses an explosive hazard and respiratory hazard
Control:
• Providing ventilation to dilute and remove methane where is concentration is <1%
and is often vented to atmosphere
• Pre-Draining methane, called degasification of the post -drain methane. i.e drilling
boreholes to allow methane to naturally vent out and is compressed and sold.
• Flaring – When utilization is not economically feasible .

4. Coal Bed Methane Drainage Operating flare @ Trona mine
Optimizing Energy Recovery with
Near‐Zero Methane Emissions Mining

5. Sulfur Dioxide:
• The sulfur in coal exists in coal both in organic , inorganic and pyrite form
• SO2 is produced when sulfur in coal reacts with oxygen.
• Copper is naturally found as sulfide ores and SO2 is released during meatal
processing stage ,Copper pyrite – CuFeS2.
• The other sources of sulfur dioxide emissions are vehicle exhaust and from
industrial processing (98%)
Control:
• The most common method is channelizing the SO2 on to a sulfuric acid plant and
catalytically oxidized SO2 into SO3 which is then converted into sulfuric acid. And
can be later used for electrolytic refining.
• By using scrubber system.

6. .
Generally 2 to 12 % SO2 gas can be economically treated in plants that produce sulfuric acid in the
presence of vanadium catalyst
SO2 + 0.5 O2 → SO3
SO3 + H2O → H2SO4
Scrubber system consist of a Scrubbing liquor
that is bubbled through lime Ca(HO)2,
limestone,CaCO3 and water forming Gypsum
CaSO2
SO2 converted to Sulfuric acid through contact
process

7. VOCs:
• The sources of VOCs during mining are vehicle exhaust and equipment leaks,
solvents for cleaning and degreasing, and fuel storage and combustion.
• These gases react with sunlight to form ground level ozone, Photochemical smog and
other secondary pollutants
Control:
• Premaintenance and handling procedures
• Vapor recovery equipment.
• By recapturing using activated carbon, silica gel, zeolite, or activated alumina .the
most common method is the fixed bed system and canister system.
• Destructive method such as Flaring and combustion.

8. Vapor recovery equipment.

9. Nitrogen oxides:
• The sources of NOX in mining are vehicle exhaust and blasting.
Control:
• Toxic fumes during explosion can be avoided by using properly formulated
explosives, avoiding deteriorated or contaminated explosives, ensuring proper
confinement.
• Using advanced emission control technologies such as an electrocatalytic reduction
to meet exhaust standards.

10. Mercury :
• Mercury can occur as an impurity in copper, Zinc , Nickle, and lead ore.
• Mercury emissions have been noted in rock piles, heap leach pads, stock piles,
tailings, and open pits and get volatilize.
Control:
• One of the simplest methods of mercury control is using a retort.it is an airtight
vessel in which the amalgam of mercury can be heated and the gaseous mercury
retained and condensed back into liquid mercury.
• Using fume hoods with condensers or collection systems can be used to prevent
exposure to mercury vapors and subsequent release into atmospheres with a
condenser system.

11. Mercury control is using a retort

12. Particulate Matter:
• Particulate matter is emitted during surface mining operations due to overburden
removal, drilling, blasting, loading, unloading, transportation, wind erosion, and
vehicle exhaust.
• Lead particulates are of major concern in mining which is naturally found in many
metallic ores.
Control:
• Containment -prevention of dust through mechanical means. These include enclosing
conveyors, minimizing dump heights and rates from trucks, resurfacing of high traffic
areas, installing windbreaks, screens, etc.
• Suppression - using water or chemical application (foaming agents or surfactants)
• Collection – baghouse, wet scrubbers (spray towers, cyclonic spray towers, dynamic
scrubbers tray towers, venturi scrubbers, orifice scrubbers, packed towers,
condensation scrubbers, and charged scrubbers, Electrostatic precipitators)

13. Enclosed conveyors
Wind barriers
Wind barriers

14. Other measures:
• Considering distancing from buildings and residential areas based on the wind conditions.
• Makin the site smaller as possible as a larger site can cause larger impacts.
• Avoid mining on hills, consider mining on down site so that wind is not strong.
• Planting trees can prevent air pollution - Green belt
• Mining should be done when the amount of moisture in the soil is greater than the amount
which produces dust.
• Design of the roads for fuel-efficiency.
• Better operation and maintenance of the roads and supporting structures.
• Reducing airflow in the stockpiles by covering to avoid dust being carried away.
• Adding moisture or chemical binders to raw materials before dumping, tripping,
conveyance, and transferring.
• Installing wind barriers over the conveyors and modifying it to avoid vibrations

15. ©flicker

16. Reference
• Air pollution control engineeri - De Nevers, Noel, 1932
• EPA Guidelines for Air pollution Control.
• Environmental Impact of MINING AND MINERAL PROCESSING Management, Monitoring, and Auditing
Strategies RAVI K. JAIN, Ph.D., P.E.
• https://saferenvironment.wordpress.com/2008/10/15/coal-bed-methane-cbm-drainage-from-underground-
coal-mines-%E2%80%93-safer-and-eco-friendly-option-of-green-energy/.
• http://www.unece.org/fileadmin/DAM/energy/se/pdfs/cmm/pub/BestPractGuide_MethDrain_es31.pdf
• https://www.epa.gov/sites/production/files/2016-03/documents/cmm-flaring-flyer-sept-2014.pdf
• https://www.ucsusa.org/resources/coal-and-air-pollution
• https://www.yokogawa.com/in/library/resources/application-notes/sulfur-dioxide-scrubber-ph-control/
• https://mogckchem.weebly.com/the-contact-process-in-the-manufacture-of-sulfuric-acid.html
• https://www.sciencedirect.com/science/article/abs/pii/S0009254113003835

17. Pictures Credits
• ©Unsplash.com,Flicker.