Dust control practices in open cast mining industry.

Title- “DUST CONTROL PRACTICES IN OPEN CAST MINING ACTIVITY”
Group Members:
1) Kishan Kumar (R136215015)
2) Subhash Kumar (R136215033)

Mining is a dust prone occupation and almost every major process in mining
contributes to the atmospheric load of suspended particulate matter. The growing
emphasis on open cast mining operation in recent years to achieve ever increasing
production targets has further increase the problem of air pollution. Major sources
of air pollution in open cast mines are drilling, blasting, overburden loading and
unloading, material handling and workshops. Prolonged exposure of this dust is
known to cause various respiratory diseases including deadly pneumoconiosis
among the miners Dust is one of the most vital problems faced by the open cast
mining industry as It affects production tremendously.
Keywords: Silicosis, Pneumoconiosis(CWP), Central Institute of Mining and fuel
Research(CIMFR).

 In mining activity excavation is basically done by drilling and blasting and
can be pinpointed as contributions to dust generation.
 With an increased level of mechanization and the pressing demand to boost
production for minimizing the supply gap, generation of air borne respirable
dust is increasing.
 Prolonged exposure of coal mine dust is known to cause various respiratory
diseases like pneumoconiosis, silicosis, bronchitis, asthma.
 Air-borne dust from mining activities spreads over nearby populated areas
and crops causing harmful effects in many ways to the people, vegetation,
forests, animals and water resources and also shortens the life of lubricants
of Heavy Earth Moving Machinery (HEMM).

1. To identify the most vulnerable sites of dust generation & its
quantification.
2. To check the fraction of respirable dust & suggest suitable techniques
for its mitigation.

 Dust extractor for jack hammer
Drilling.[4]
Dust Extractor is comprised of a hood with a cushion
base, an elastic collar attachment to cope with
intermittent hammer motion and an elastic collar grip on
the drill Rod. During drilling, the cuttings are transported
to the hood by the scavenging compressed air, which
eventually gets channeled through the filter bag. The bag
lets the air go out and retains all the dust.
 Dust arrester for large diameter deep
hole drilling in open pit mines[4]
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 .
The hole in the ring cushion is smaller than that of drill
rod, but flexible enough to let the larger drill bit pass
through which a specially shaped long. During drilling,
part of coarse dust gets deposited around the base collar
and fines pass through the filter bag.
Fig 1. Dust extractor for jack hammer drill
Fig 2. Dust extractor for large dia. drilling

Rubber Skirting Installed on Drills [3]
Drills have been equipped with rubber skirting to limit
dust dispersion during drilling Skirting consists in a
rubber curtain affixed below the drills
Fig 4. Green wall near o/c mines
Boom Sprayers Mounted on Tank Trucks
A full-time employee sees to water truck management
and logistics. His role is to optimize road watering
procedures and moisture Levels Boom sprayers have
been mounted on tank trucks and Temporary canvas
covers have been installed over several conveyor
components.
Fig 3.Rubber curtain used to control dust generating
during drilling
Green Wall
The Green Wall is a mitigation berm between the mine
and the town The wall is 15 m high and 1.3 km long. It
reduces noise and dust The current wall was completed
in 2011 and there are plans to extend it during the mine
extension project.
Fig 5. Sprayers used in regular intervals

 Conventional and most practical solution of dust suppression normally
uses water on a very high rate but water applied in the conventional way
gets dried up fast, and its replenishment at frequent intervals (up to 15
times a shift) which adds significant cost and during summer days water
not easily available, so use other cost effective methods that is easily
available to suppress dust emission.
 Mining activity generates huge amount of dust varies in different particle
sizes(SPM) between 0.1- .10 microns. The most significant fraction of
SPM is the respirable size that is larger than about 0.1 microns and smaller
than 5 microns. Respirable dust exposure has long been known to be a
serious health threat to workers, so there must be introduction of regular
checkup camp for miner’s to prevent them from fatal death.

First we have to measure the amount of dust generated by the sources considering
various equations, factors.
 Gravimetric Sampler: This sampler consists of a constant-flow sampling pump, a size-
selective cyclone, and a filter cartridge. In metal/nonmetal mining operations, the pump
should be operated at 1.7 lpm. The 10-mm Dorr-Oliver cyclone separates the oversize dust
from the respirable fraction .The oversize dust is deposited into the grit pot at the bottom of
the cyclone, while the respirable fraction is deposited onto a 37-mm-diameter polyvinyl
chloride (PVC) filter.
Fig. Gravimetric Sampler

where E = emission factor in kg per vehicle kilometer travelled (kg/VKT)
k = particle size multiplier (dimensionless)
s = silt content (<75 um) of road surface material, (percent)
S = mean vehicle speed, (km/h)
W = mean vehicle weight, Mg (ton)
w = mean number of wheels (dimensionless)
p = number of days with >0.25 mm of precipitation per year.

E = emission factor kg per metric ton transferred
(kg/Mg)
k = particle size multiplier (dimensionless)
U = mean wind speed, (m/s)
M = material moisture content, (percent)
WE also need to calculate the wind-rose diagram to
see mean wind speed of that area

Particle size analysis of SPM at various mine site with the use of micron
photosizer.[2]
Photosizer Size range Percentage weight in the range
(micron)
Ambient air Feeder breaker Haul Road
 0–2 5.4 3.8 5.9
 2–5 5.3 4.5 5.3
 5–10 8.5 10.6 12.1
 10–20 31.2 28.7 26.2
 20–40 28.6 42.3 36.0
 40–60 15.5 7.2 11.3
 >60 4.6 2.9 3.2
 This much amount of dust generation led to much serious health related problems,
so our projects describes about what are the most suitable technique to tackle this
much amount of dust .

 Haul road- at the height of about 2m on the debris at one side of
the haul road.
 Haul road near the box cut at about 3m above the ground.
 At a distance of about 100m from the face and 2m above the
ground.
 At Shovel dumper loading point above the immediate bench.
 Outside the mine periphery near to residential area.
 Public transportation road near to habitant area.
Location’s to measure SPM level in the mine

Fig 6. Amount of dust generated during drilling in an o/c
mines
Drilling produces the largest quantity of respirable dust per unit weight during the shortest time.
A study reports up to 1.46 kg of respirable dust generation per meter of drilling by a 250 mm
diameter drill in iron ore opencast mines. presents the level of dust generation during drilling in
coal, limestone and iron ore which reveals that air borne dust generated in drilling increases with
drill diameter and rock hardness

Preventive Technique
Dust arrester for large diameter deep hole drilling
in open pit mines
The drill rod is introduced through the top ring
cushion and through the base plate collar till the
drill rod touches the ore body. The dust filter bag
is fully stretched. The hole in the ring cushion is
smaller than that of drill rod, but flexible enough
to let the larger drill bit pass through. During
drilling, part of coarse dust gets deposited around
the base collar and fines pass through the filter
bag. The base cushion gets pressed against coal
strata due to the weight of dust settling inside the
box, Figure 6. Dust arrester for large diameter deep
hole drilling

Dust emissions by blasting are of concern to both mine operators and surrounding communities.
The quantity of dust produced, and the effects of its dispersal depend substantially on geological,
blasting and meteorological conditions. The blasting dust cloud is normally visible for several
minutes. Most of the dust settles in and around the mining area, although some may be dispersed
to long distances before settling down. Some of the settled dust is raised again by mining activities
such as moving vehicles.
Fig. Dust Generated after blasting

Water Filled Ampoule in Stemming
PVC ampoules (water filled, or gel filled) have been used prior to 1980 in
underground coal mining in United Kingdom. They were used as a safe stemming
material. They significantly reduced dust and fumes from blasting. Water filled plastic
bags were permitted device for stemming for small diameter short holes.
Figure 7- Blast hole having
water filled Ampoule

Preventive Technique that we want to be
implemented at the blasting site
Fig. Fog Cannon Dust Suppression System
Fog Cannon Dust Suppression System
Fog cannon have been specially designed for problems of airborne dust particles generated by
open cast mining activities, to suppress dust via a mist cannon that can spread to a dist. Upto.
250m, also have automatic rotation to 330degree, with a adjustable elevation to 45 degree. With
a no. of fog cannons directed at a blasting site the airborne particles can be fully suppressed

3. Dumping
Ore is normally loaded into haul trucks from the pit or quarry and driven to the primary crusher
location. This ore is then either dumped directly into the primary hopper, which feeds the
primary crusher, or it is dumped in a stockpile. If it is stockpiled, a front-end loader then takes
the ore product and dumps it into the primary hopper. In either case, a dust cloud is created
during this dumping process.
Fig. Dust generated during dumping

There is one dust source that must be addressed during this dumping process is using curtain
method or staging curtains. Staging curtains, also called stilling curtains, are curtains of varying
lengths which physically prevent the natural tendency for dust to blow out of the primary dump
as a large volume of product is dumped. By minimizing the airflow, effect the amount of dust
released from the dump site is reduced.
Figure 8. Staging curtains reduce
dust billowing during dumping

Preventive Technique that need to be implemented
Fog cannon have been specially designed for problems of airborne dust particles generated by
open cast mining activities, to suppress dust via a mist cannon that can spread to a dist. With a
no. of fog cannons directed at a open dumping site/stockpile area the airborne particles can be
fully suppressed, because every where we can’t covered area need to be dumped in open air..so it
is a much better technique then covered dumping method.
Fog cannon

Respirable dust generated by out bye sources can be in airstream and remain airborne across the
entire mining environment which can impact the dust exposure of all personnel on the face. The
crusher is the most significant dust-generating source. The breaking of coal and rock in the
crusher generates large quantities of dust, which can lead for generation of PM 10, PM5 particles
and can led to major diseases.

Instead of full covered the dumping area(i.e. not possible, need to full cover the crushing discharge area
 Fully enclosing the crusher. Recent surveys done to found result over that crushers
to be fully enclosed. However, there was not a universally applied technique for
enclosing the crusher. The common practice is to apply a combination of steel
plates, strips of conveyor belting, brattice, and/or foam to seal the crusher units
along their entire length. In addition, conveyor belting covering the entrance of the
crusher has been effective in keeping dust from boiling out of the enclosure and into
air and continuous spray of water over the discharge end.
Fig.11 Showing complete covered crusher point and water spray
system

5. HAUL ROAD
Unpaved haul roads in coal mines are a veritable source of dust pollution supporting normally 10
to 15 mm of dust on its surface. Dust from haul roads gets lifted and floats in the air during
movement of trucks and forms a dust cloud. With an increase in the weight of trucks, speed and
frequency of traffic, the cloud may appear to be continuous causing delays and difficulties.

Control measures
Chemical dust suppression
Chemical dust suppressants are nowadays
gaining more acceptance in the industry for
controlling dust at haul roads probably due to
the fact that the application methodology for
these chemical dust suppressants fits well to the
conventional water spraying keeping in mind
ensuring environmental safety and hazard
issues.
one company is Syntron Industries,
Ahmadabad made a chemical dust
suppressor Dustron PC in collaboration
with CIMFR, Dhanbad . Director
General of Mines Safety
DUSTRON – PC (LIG) treatment is carried out every day in the second half
of first shift. During the beginning days of treatment, quantum of
DUSTRON may vary in the ratio of1:2500 to 5000 depending upon the soil
conditions, temperature, humidity, load and speed of Dumpers. DUSTRON
and water should be in a ratio of 1: 2500 to 5000 (1 Kg of DUSTRON to be
mixed with 2500 to 5000l. of water).

Pattern of applications of DUSTRON -PC
DUSTRON and water should be in a ratio of 1: 2500 to 5000 (1 Kg of DUSTRON to be mixed
with 2500 to 5000l. of water).
• 1st day to 3rd day - 3 times
4th day to 6th day - 2 times
7th day to onwards - 1 times
Satisfactory performance period:
Satisfactory performance period 1:2500 – The satisfactory Performance will be
observed
within 07 (Seven) days with application pattern maximum. Result will observe from
3rd day with necked eye.

Depending upon the distance of the source fog cannon generally varies but most widely used
has a range of 200m. And need to be used popularly at the railway sidings.

Depending on the amount of dust moves out of the mine to the outer periphery different types of
technologies to be adopted.
Formation of
1. Green Wall around the mine periphery is a good idea from
environment perspective and also for dust not to move out from mine
to near by residential area
The Green Wall is a mitigation berm between the mine and the town
The wall need to be approx. 15 m high and 1.3 km long. It reduces
noise and dust The wall need to be there in plans and to extend it
during the mine extension project.

2. Use of mobile dust suppression system
This is a mobile dust suppression
system which includes
pressurized water eject from
sprinkler over the dust generating
sources. A water tanker fitted at
back of 20000 liter is used. 3
water nozzle is equip at a pipe
which means large volume of
mist and creates a spray like fog
cannon at a very minimum rate.
mobile dust suppression system

 Canopy curtain method must be adopted at transfer points particularly
crushers houses.
 New advanced technologies to be adopted like Coal dust briquetting
system for converting coal dust collected from coal mine road surface
into coal briquettes.
 Every open cast mines must be surrounded by tress like walls for
distance 50m.
 Use of various hydrocarbon aliphatic compounds(manufacturer- Syntron
inds.) to suppress dust over the haul road and also reduce water
consumption.

In our project we give idea to use a sealed dust collector box though which drilling rod
pass and the dust generated is collected in the box, for making this new system that can
help in generating a power source from waste (coal dust ) to be used again.[1]
‘Coal dust briquetting system’ for converting coal dust collected
from coal mine road surface, drill chamber into coal briquettes.
Dust collected by truck mounted dust collecting system from mine road surface and also the dust
collected from the sealed drilling box will be discharged into ‘Coal dust briquetting system’ for
converting coal dust into coal briquettes. The weight of coal dust and binding agent will be
measured at weigh batcher and those will be poured into the mixing drum with predefined
quantity. Water will also be mixed with predefined quantity , then the material will be passed
through two briquetting rollers and coal briquettes will be discharged on belt conveyor at the
bottom of roller.

Dust control practices in open cast mining industry.

a) Steel platform for plant, size – 3.3 × 13 m (approx.)
b) Hopper to collect coal dust, capacity – capacity 6 to 8 m3 (4 to 5 t)
c) Weigh batcher (hopper) for coal dust – capacity 500 to 600 kg
d) Weigh batcher (hopper) for binding agent – maximum capacity 50 kg
e) Mixing drum or agitator – capacity 200 to 250 kg per batch
f) Briquetting machine – maximum capacity 2 to 3 t/h
g) Air compressor for operating air actuated valves of hoppers, weigh batcher and
agitator.
h) Belt conveyor for shifting coal dust to weigh batcher from coal hoper – length 700
to 1010 cm
i) Belt conveyor (size as per the requirement) for transporting final product (coal
briquette) from briquetting system to the outer bin of final product through heating
chamber
j) Heating arrangement (hot blower) for drying final product (coal briquette)
k) Water tank – capacity 200 to 250 liter
l) Water pump with flow meter
m) Air actuated valves for coal dust collecting hopper, weigh batchers and outlet of
agitator or mixing drum
n) Panel board for entire automatic operation of the system

Diagram of briquette making model

 [1]CSIR-Central Institute of Mining and Fuel Research, Dhanbad
Invitation for Expression of Interest for Fabrication and
Commercialization of ‘Coal Dust Briquetting System’.
 [2]. Banarjee.G K, Srivastava.K. K and Chakraborty.M. K, “SPM is the major
pollution in open cast mining” – a case study, 25th January 2001.
 [3]Nair, P K and Sinha, J K, 1987. “Dust control at deep hole drilling for
open pit mines, development of a dust arrester”, Journal of Mines, Metals
and Fuels, Aug 1987.
 [4]Pandey Jai Krishna “ DUST CONTROL PRACTICES IN THE INDIAN
MINING INDUSTRY” 2012 Coal Operators’Conference The University of
Wollongong.

Dust control practices in open cast mining industry.

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