This document discusses dust monitoring and control in opencast metal mines. It begins by defining particulate matter and dust, then discusses major sources of dust generation at mines including mining faces, haul roads, crushing plants, and waste dumps. It outlines standards for dust monitoring at work zones and ambient air quality. Monitoring methods like gravimetric sampling are described. The document discusses health effects of dust inhalation and various dust control methods that can be generalized to all mining operations or specialized to specific processes like drilling, blasting, and in-pit crushing. It provides a case study on dust control practices in iron ore mines in Eastern India.

1. DUST
MONITORING
AND
CONTROL IN
OPENCAST
METAL MINES
Anmaya Naik
14MI33006
Adil Philip Mathew
18MI60R13
Environment
Control in
Mines

2. Introduction
MAJOR MINE AIR POLLUTANTS:
• Particulate Matter: Dust of various
sizes
• Gases: Sulphur Dioxide, Oxides of
Nitrogen, Carbon Monoxide etc. from
vehicular exhaust.
DUST:
particles varying from
1mm to less than 1µm
PARTICULATE MATTER
This complex mixture includes
both organic and inorganic particles,
such as dust, pollen, soot, smoke, and
liquid droplets

3. Sources
1) Point Source: A point source is a source that is at a fixed point (location) and that emits a
significant amount of pollutants
2) Area Source: An area source is a group of sources that together contribute a significant
amount of pollutants, even if one or more of the sourcesalone would not be very significant.
Area Sources of Dust Generation / Monitoring
Location
Mine face / benches Drilling, Excavation & Loading
Haul Roads / Service
Roads
Haul roads leading to Ore Processing
Plant, Waste dumps & Loading areas and
Service Roads.
Crushing Plant Run-off-mine unloading at Hopper,
Crushing Areas, Screens, Transfer Points
Screening Plant Screens, Transfer Points
Ore Storage & Loading Intermediate Stock Bin / Pile areas, Ore
stock bin / pile
areas, wagon / truck loading areas
Waste Dump Areas Active waste / reject dumps

4. Sources(Cont.)
Flowchart of Pollution
Generation at different
stages of mining

5. Standards
Work zone Environment Ambient Air Quality(AAQ)
Point Source: 100mg/Nm3
Stack Height: H = 74 Q0.27 m
*Height of the stack should be at
least 2.5 m above the nearest building height.
But in any case, stack height should
not be less than 15 m
Area Source :
• SPM: 1200 μg/m3
• RPM: 500 μg/m3
*of 25 m (± 5 m) from the source of
generation in downwind direction
considering the predominant wind direction
Pollutant
Time Weighted
Average
Concentration in Ambient Air
Industrial,
Residential, Rural
and Other Area
Ecologically
Sensitive Area
(notified by GoI)
SO2, μg/m3
Annual* 50 20
24 hours** 80 80
NO2, μg/m3
Annual* 40 30
24 hours** 80 80
PM10, μg/m3
Annual* 60 60
24 hours** 100 100
PM2.5, μg/m3
Annual* 40 40
24 hours** 60 60
O3, μg/m3
8 hours** 100 100
1 hour** 180 180
Lead (Pb), μg/m3
Annual* 0.50 0.50
24 hours** 1 1
CO, mg/m3
8 hours** 2 2
1 hour** 4 4

6. Physiological effects
Health Effect
• Systemic toxic effects caused by
absorption into the blood
• Allergic and hypersensitivity
reactions
• Bacterial and fungal infections
• Lung scarring and fibrosis
• Cancer
• Irritation of the mucous membranes
of the nose and throat
• Pulmonary disease (e.g. coal
workers' pneumoconiosis (CWP)
and chronic obstructive pulmonary
disease (COPD) such as bronchitis
and emphysema)
Dust Particle Content
Lead, manganese, cadmium, zinc
Certain woods, organic and inorganic
chemicals
Viable organisms or spores
Asbestos, quartz (crystalline silica)
Chromates, asbestos, quartz
Acid, alkali, other irritating particles
Coal dust

7. DUST MONITORING
GRAVIMETRIC SAMPLING
Air is passed through a filter, the filter is then weighed to
determine the amount the particulate matter collected
High volume air samplers typically sample more than 1500 cubic
metres (m3) of air over a 24-hour period, while low volume air
samplers draw through only 24m3 of air, or less
The inlet removes particles larger than 10µm by using their
inertia to trap them on a greased plate, while smaller particles
pass through the instrument onto the pre-weighed filter
Frequency of Sampling:
• Fugitive dust (SPM & RPM) shall be monitored at all the locations
for 8 hourly basis in any working shift at least once in a month other
than monsoon.
• Ambient air quality monitoring shall be monitored as per the
National Ambient Air Quality Standards i.e. twice in week at each
location for 24 hourly at uniform intervals so that minimum 104
measurements can be taken in a year.

8. DUST CONTROL
CONTROL PRACTICES
 Dust consolidation- Dust consolidation is normally practiced for settled dust which
becomes airborne in favourable condition e.g. haul roads of open cast mines
 Dust capture- Dust collection or capture is resorted to when it is airborne. In these cases
dust is collected close to its source of generation for effective result and therefore the
method is useful for controlling dust generated in localised spaces or point sources like
drilling, blasting, crusher house and conveyor transfer points with the help of special
types of dust capture arrangement.
Control Methods can be classified into two categories:
• Generalized Method: No changes to the existing mining method is required
• Specialized Method: Changes to basic unit of operation is required

9. General Dust control Methods
• Land Clearing & Top Soil Removal:
Control options during mining, loading and dumping of topsoil and overburden are generally
limited to dust suppression by watering. Scheduling these activities to coincide with favourable
winds and weather conditions may be option.
• Drilling and Blasting:
Watering of the blast area following the charging of blast holes with explosives may help.
Another method that can be effective in protecting areas adjacent to the mine from dust
pollution is to avoid blasting under unfavourable wind and atmospheric conditions.
• Waste Rock Dumps:
a) It is desirable to plan the waste dump rehabilitation to occur as early as possible in the life of the
mine.Establishing the final faces of waste dumps early and revegetating these surfaces will
significantly reduce wind erosion.
b) Dry exposed tailings can be a problem in climates with strong seasonal rainfall. It needs
appropriate planning and design of the impoundment and the associated water circuit in order to
accommodate seasonal events.
c) Alternative methods which still offer long term dust mitigation include the in situ inducement of
permanent crusts that are resistant to erosion.

10. General Dust control Methods(cont.)
• Transportation:
Fugitive dust emissions are produced by
the contact of the tyres with the unsealed
road surface and are affected by the total
distance travelled
• Applying water, or a mixture of water
and chemical for dust suppression on
mine haul roads,
• Compaction & gradation and drainage
on both sides of haul roads
• Chemical treatment of permanent road
• Proper maintenance of transport
vehicles

11. General Dust control Methods(cont.)
• Processing, Crushing and Screening:
Source: Methods:
• Plant Equipment
• Dump Hopper
• Conveyers
• Storage Stockpiles
Dust Proofing
Three sided, roofed sheds for truck
dumping, with low volume high
pressure adjustable water atomising
sprays actuated at the time of
dumping.
Sprays at transfer points to wet dust
and
particles and prevent liberation,
mist/fog
systems to increase fall out rates.
Fixed water cannons, or vehicular
based
sprays for small stock piles. Drainage
often required at stockpile base and
foundations.

12. Specialized Dust control Methods
1) MEASURES FOR DRILLING
a) DUST ARRESTER- Up to a few hundred kilograms of broken dust is generated from each drill hole. The
dust is finer than what is formed in other mining operations and contains a significant proportion of respirable dust.
The dust arrester is a rectangular box with a ring shaped foam cushion washer at the top, a collar base plate with
a cushioned bottom, and a large opening on one side to which a specially shaped long and tough filter bag is
attached. For dust collection, drilling is carried out through this device

13. Specialized Dust control Methods(cont.)
b) WET DRILLING-
Water will flow through water hose from the water tank and finally will be discharged into the air delivery pipe. The
pressurised air will carry the atomised water inside the delivery pipe through Rotary Head Drill pipes and will
finally discharge through the Drill bit inside the hole. Dust generated due to the cutting action of the drill bit will be
suppressed by the spray of water inside the hole itself. As a result there will be no air borne dust near the drill.

14. Specialized Dust control Methods(cont.)
2) Blasting
a) Split Charge Blasting techniques with Air Decking by Gas:
Melinikov has suggested that air decks provide a mechanism by which a secondary stress wave can be readily
and inexpensively generated. The theory postulates that shock wave reflections within the hole produce a
secondary stress wave which extends micro fractures network prior to gas pressurisation. According to Melnikov,
Air decks reduce the final hole pressure produced by the explosive products but increases the duration of their
action on the rock (Air deck do not affect the detonation pressure of the explosives)

15. Specialized Dust control Methods(cont.)
Split Charge Blasting techniques with Air Decking by Gas:
Area Conventional Split-Charge with GasBags
• Decking
• Fragmentation
• Flyrock
• Ground Vibrations
• Watery Conditions
• Exp.
Energy Utilisation
• Cost
No
Fragmentation is not
satisfactory
Severe
Ground vibrations are high
Can be applied in watery
conditions
Wastage of explosive
Expensive method
Comparatively
Suitable for Midcolumn, Top
& Bottom Air Decks
Fragmentation is best
Negligible
Ground Vibrations are low and
well within the statutory limits
Suitable for watery holes
energy is Better utilisation of
explosive energy
cheaper Most economical

16. Specialized Dust control Methods(cont.)
3) In-Pit Crushing and Conveyor
Transport System-
The main benefits of switching from off-
highway trucks to an in-pit crushing
system with conveyor haulage are:
• Smaller loading machines can be used;
• Less auxiliary equipment(Less dump
trucks)
• Reduced fuel costs;
• Environment friendly.

17. Case Study-Iron Ore Mines-Eastern
Zone(Odisha, Jharkhand)
Iron Ore mining in the area is being done by opencast method and is a combination of both
large mechanised mining by SAIL, TISCO, IISCO & OMC and small manual and semi mechanised mining by
private mine owners. There are around 82 operating iron ore mines in the state of Orissa and 20 operating
mines in the state of Jharkhand.
The major air pollution in this region is due to generation of dust from the movement of small private dumpers
carrying iron ore lumps from the small privately owned mine to common crushers, which are invariable of dry type
crushing and screening without any environmental protective measures. The small mining companies are mainly
using the public road as the haul road and the dumpers are observed to be running mostly in overloaded condition.
The dumpers are not covered either and the spillage of the material and repeated crushing on the roads by the
truck movement add to the dust generation. The nearby villagers are most affected and these dust forms thick
slurry after the first monsoon rains and add to the water pollution in the area. However the bigger mining
companies are using better air pollution control and management practices like wet drilling, water sprinkling at the
mine haul road, water spraying at the hopper of the crusher plants, mist spraying at the fines dumps and using
covered conveyors and thereby minimizing dust dispersion to the nearby residential areas.

19. Parameters Annual Maximum
(µg/m3
)
Annual Average
(µg/m3
)
Annual Minimum
(µg/m3
)
98 Percentile
(µg/m3
)
SPM 1289 191 56 534
RPM 350 93 28 314
Parameters Annual Maximum
(µg/m3
)
Annual Average
(µg/m3
)
Annual Minimum
(µg/m3
)
98 Percentile
(µg/m3
)
SPM 2531 305 102 1321
RPM 697 215 65 560
AAQ Variation of RPM and SPM (Eastern Zone)
Variation of RPM and SPM in workzone (Eastern Zone)
Monitored data:

20. References
▸COMPREHENSIVE INDUSTRY DOCUMENT ON IRON ORE MINING , CENTRL POLLUTION
CONTROL BOARD (Ministry of Environment and Forests, Govt. of India) Parivesh
Bhawan, East Arjun Nagar, New Delhi – 110032
▸Jai Krishna Pandey, 2012, Dust control practices in the Indian mining industry, J.K.
Pandey, Dust control practices in the Indian mining industry, 12th Coal Operators'
Conference University of Wollongong & the Australasian Institute of Mining and
Metallurgy, 2012, 185-192
▸High and Low volume air sampler,Queensland Government,27 March 2017,
Queensland,Australia[7th November 2018].

21. THANK YOU!!