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1. Indian Journal of Air Pollution Control Vol. V No. II September 2005 pp 70-76
Vegetation for Cement Dust Control and Mine Reclamation
Y. K. Saxena* and Harendra Kumar**
*Research Scholar, Ch. Charan Singh University, Meerut &
Vice President – EHS, Gujarat Ambuja Cements Limited,
248, Okhla Industrial Estate, Phase III, New Delhi-110 020
** Principal, Devanagri College, Meerut-250 001
(*E. Mail: yks@ambujamail.com)
Abstract
Indian cement industry was inherently known for its pollution. Today its environmental performance has now
assumed an important significance due to availability of technology, advanced mining practices and reclamation.
The cement manufacturing process deteriorates the environment from mining of limestone to the finished
product. Vegetation not only has a unique ability of harvesting solar energy through photosynthesis but also play
a vital role in improving aesthetic environment and air quality. However, due to state-of-the-art technology
available, the impact of suspended particulate matter has been minimized with the installation of air pollution
control equipment. The appropriateness of sustainable mining, air quality and the role of plants for better
ambient air quality as well as its impact on plants have been discussed.
Key words: SPM, EIA, Ambient air quality, Plants, Reclamation.
Introduction
Air pollution has long been known to have an adverse effect on plants. Initially, sulphur dioxide was
considered as a dangerous pollutant. Now, with the advent of various new industrial processes, the
range of harmful pollutants, mainly suspended particulate matter (SPM), has multiplied tremendously.
Presence of any other gas or solid in the air degrades its quality and when the concentration of the
extraneous gases and solids exceed certain limit, they adversely affect not only the living beings but
also the plants.
Air pollution is thus defined as "the presence of any substance in the atmosphere in such a
concentration that may be or tend to be injurious to human beings, other living creatures, plants or to
the atmosphere itself". In other words, it is the presence of undesirable contaminants in the air in the
form of gas, smoke, fume, mist and dust, etc., in such quantities and of such duration as to become
injurious to human, plant and animal life, harmful to our living, and to historical monuments and other
structures. Various gases and particulate matters emitted into the atmosphere by industrial stacks and
energy generating units, in concentrations significantly higher than the natural level or imbalance of
constituents of air are referred as air pollutant.
Plant injury caused by air pollution is most common near large cities, industries such as
refineries, power plants as well as cement industries, if pollution is not controlled. Damage in isolated
areas occurs when pollutants are spread long distances by wind currents. Factors that govern the extent
of damage and the region where air pollution is a problem are type and concentration of pollutants,
distance from the source, length of exposure and meteorological conditions.
Scenario of Cement Manufacturing in India
The first cement plant in India was commissioned in 1914 with installed capacity of 10,000 tonne per
annum at Porbandar, Gujarat by Indian Cement Company Limited. Since then industry has come a
long way. At present there are 128 large cement plants in India having installed capacity of 152.14
million tonnes and actual production of 125.56 million tonnes (CMA, 2004). India ranks world's
second largest cement producing country after China in both installed capacity and annual production.
The modern Indian cement plants are comparable to the world best in technology absorption, energy
conservation as well as environment pollution control.
In the above context, let us take the case of The Gujarat Ambuja Cements Limited (GACL). A
cement plant has been set up by this company at Darlaghat, Dist. Solan, Himachal Pradesh in 1994
with the corporate philosophy of 'Sustainable Development.' The plant covers approximately 50 ha. of
non-prime land with a mining area of about 3-km away from the plant site in village Kashlog. The
mines are open cast captive mines and limestone is brought to plant by overland belt conveyor passing

2. through tunnels. A Glass Bag House is attached to the Raw Mill and Kiln section. The uniqueness of
this plant is that the bag filters have been installed at each loading, unloading and transfer points to
minimise dust emission. A Sewage Water Reclamation Plant for an average flow of 220 cu. m/day
treats domestic wastewater and 100% treated water is recycled for cooling and other purposes. An
Environmental Management Division has been set up with Lab to monitor air and water emissions and
meteorological conditions. Nurseries have been set up in the plant and mining area to improve the
vegetation in the vicinity of plant and mines. The emissions from the plant are below 50 g/m3
and
noise and vibration in the mines are maintained much below the stipulated standards.
Cement Manufacturing Process
There are three distinct processes for manufacturing of cement, mainly wet process, semi-dry process
and dry process. Today with the advancement of technology, dry process has been adopted with pre-
calciner. Cement is manufactured (Saxena, 1990) in four basic stages:
- Quarrying and crushing,
- Grinding and blending of raw materials,
- Clinker production, and
- Finished grinding
The manufacturing process for cement production is given in Figure 1.
Cement manufacturing due to dry process contributes significantly to air pollution, not only in
the vicinity of the works but also in the surrounding area, from mining of raw material to the end of
process. Large quantities of pulverized material are handled at each stage of manufacturing from
crushing of raw material to final packing of cement, resulting emission of dust and in turn causing air
pollution.
Environmental Pollution from Cement Manufacturing
Cement Industry is known for contributing to atmospheric pollution in terms of gaseous and
particulate matter emitted from stacks and other sources. However, there has been a growing
realisation in the Indian cement industry to abate particulate emission as per the standards specified by
Government regulatory agencies.
Cement Plants produce a considerable quantity of particulate matter as a result of the continuous
feeding of raw materials into cement kiln, and rapid counter current flow of combustion gases over
raw feed. Particles that become entrained in combustion gases and are removed from the kiln by
exhaust gases are known as cement kiln dust (CKD). This material is composed of unchanged raw
materials, dehydrated clay, calcined limestone, ash from fuel and newly formed minerals produced by
the chemical transformation of raw materials during the cement manufacturing process.
Air Pollution Control Equipment (APCE) is provided to control dust emitted from various stack
sections of cement manufacturing. APCE such as cyclone, multi cyclone, electrostatic precipitator
(ESP), bag filter (BF), and wet scrubber are used to collect dust from stacks attached to different
sections (BDPL, 1991). The efficiency of glass bag house, bag filters as well as ESP is 99.9%. A
continuous monitoring system has also been installed to monitor the major stacks of cement plant. A
water spraying system installed at the crusher reduces further fugitive emissions. The selection of
APCE depends upon various factors like size of dust particles, flue gas characteristics, collection
efficiency, emission limit and techno-economic feasibility of the control system. APCE recommended
for different sections of the cement plant is summarized in Table 1.
The total quantity of the particulate emission from all the fugitive dust sources is quite
substantial and according to a rough estimate, it varies from 10-30% of the total emission from a
cement plant. The methods employed for fugitive dust control in cement industry are local exhaust
ventilation and water spray system. The impact of fugitive dust emission on the surrounding
environment is immediate as compared to the stack emission because the sources of fugitive dust
emission are fairly close to the ground and pollutants are likely to appear in and around the vicinity of
plant.

3. Table 1: Recommended air pollution control equipment for different sections
S.No. Section Dust Collector
1. Crusher Bag Filter
2. Raw Mill Bag Filter / ESP
3. Kiln Bag Filter / ESP
4. Clinker Cooler ESP/Bag Filter with heat Exchanger
5. Coal Mill Bag Filter / ESP
6. Cement Mill Bag Filter / ESP
7. Packing Plant Bag Filter
The dust generation sources are of two types:
i. Point sources: like stacks, vents connected with crusher, raw mill, kiln, cement mill, packer, etc.
The ground level concentration (GLC) from stacks varies with meteorological conditions.
ii. Fugitive sources: like open-air handling and storage of raw materials and clinker, conveyors,
transfer points, leaking joints, loading and unloading operations etc. Fugitive emission from raw
materials storage depends upon the moisture content of the materials. Fugitive sources mainly
affect the working environment in a factory.
Enclosed storage facilities (i.e. silos, covered stock pile) have been developed to store various
materials such as coal, clinker, gypsum and fly ash. This has reduced the level of dust in and around
the cement plant. GACL has provided covered storage for limestone to reduce fugitive emissions. Bag
filters have been installed at all loading / unloading and material transfer points to reduce fugitive
emission. Most of the cement plants have concrete / asphalted roads within the plant boundaries and
vicinity. This has resulted in reduction of fugitive emission as well as better house keeping. So far,
emission standards for NOx and SO2 from cement kiln have not been evolved by government
regulatory agencies in India. Dispersion of these pollutants is recommended through tall stacks.
Environmental Impacts of Limestone Mining
The mining industry is one core economic activity, which has literally deep relationship with the
Mother Earth. More than 0.8 million hectares of lands is under mining, a substantial portion of which
lies in forest areas. Good limestone deposits are also available near the wildlife sanctuaries, national
parks and coastal areas. Mineral production is often not in consonance with conservation of forest
since at many places commercial reserves exists below thick forests (Mathur and Mishra, 1996). The
environmental issues, which are site specific in mining activities, include the following:
- Disturbance to existing terrestrial configuration.
- Generation of overburden.
- Run-off from surface and waste dumps.
- Rolling of material from steep slopes.
- Pollution of surface and ground water from excavations.
- Drilling, blasting, removal, storage and re-handling of topsoil.
- Particulates and gaseous emissions from transportation of materials.
- Effect on wildlife population in eco-sensitive regions.
Main problems in the mining area are rolling of stones, silting in the natural water streams as
well as vibrations due to blasting. Presently, a Rock breaker is used to avoid secondary blasting, hence
minimising noise and vibrations. Check dams as well as Toe walls / Bunds have been created
throughout the mining area to stop silting in the water streams. About 2 lakh saplings have been
planted over 40 hectares of land in the mining and surrounding areas.
Limestone mining industry is also a major contributor, not only to the material needs and
economic health of the industrialised world, but also to the development and economic growth.
Mining is also responsible for high degree of environmental disturbance with negative impacts on
ecological systems, bio-diversity including ambient air quality. Mine planning for environmental

4. protection avoids or minimises potentially adverse environmental impacts over the life of mine and
into the future by carefully considering the various components of mining. The conventional method
of mining, involving drilling and blasting, ripper - dozer, hydraulic excavators / front-end loaders,
dumpers and primary crushers, are invariably associated with adverse effects of dust, noise and
vibrations, etc. Presently, cement industry is either using eco-friendly mining technology such as
surface miner, rock breaker, etc. or minimum blasting techniques for ecological sustainable mining.
Reclamation and Vegetation
Reclamation is the process used to restore the impacts of mining on the environment. The long
objectives of reclamation can vary from simply converting an area to a safe and stable condition, to
restore the pre-mining conditions as closely as possible with all the environmental parameters intact.
Planning is the key to successful reclamation. The reclamation plan should be an integral part of the
mining plan and a clear objective must be defined for reclamation. It should take into account an
appropriate final landuse for the area. Reclamation normally comprises of the following:
- developing designs for appropriate landforms of the minesite
- creating landforms that will behave and evolve in a predictable manner,
according to established design principles, and
- establishing appropriate plantation
The species selected for plantation will depend on the future landuse of the area, soil conditions
and climate. Sometimes, if the objective is to restore the native vegetation then the species are pre-
determined (Saxena, 2002). The best time to establish vegetation is determined by the seasonal
distribution and reliability of rainfall. All the preparatory works must be completed before time when
seeds are most likely to experience the conditions they need to germinate and survive, i.e. reliable
rainfall and suitable temperatures.
Earlier plantation was used as a tool for the improvement of aesthetic environment but today it
performs an important function due to its direct influence on the soil, both at the surface, protecting
and restraining the soil, and at depth, increasing the strength and competence of soil mass. Vegetation
also affects soil moisture apart from their unique ability of harvesting solar energy through the process
of photosynthesis. Plants also play a vital role in shaping our environment, which includes
improvement of air quality, microclimate, water cycle and soil fertility. Vegetation provides one of the
natural ways of cleaning the atmosphere by absorption of pollutants i.e. gases and suspended
particulate matter. Plants grown to function as sink for air pollutants are collectively referred to as
Greenbelts.
Greenbelts (CPCB, 2000) are effective sink for gaseous air pollutants because they are:
- Good interceptors
- Major sink for carbon dioxide
- Good absorbers of sulphur dioxide
- Good absorbers of nitrogen oxides
- Good absorbers of hydrogen fluoride and
- Absorb sound waves
Greenbelts can be raised for the improvement of air quality and are commonly used for the following
purposes:
- to combat fugitive emissions of air pollutants from industries
- to lessen the impact of episodal release of air pollutants
- to protect ecologically sensitive areas
- to provide a better aesthetic environment, and
- to restore mined out land
The selection of plant species will vary depending upon the purpose of the greenery
development, type of pollutants and on climatic conditions of the area. Trees and shrubs should have
dense foliage, with a large surface area because it is the leaves, which absorb the air pollution. For
effective removal of pollutants it is necessary that:
- plants grow under conditions of natural nutrient supply (for health and vigour of

5. growth),
- absence of water stress to maintain openness of stomatal apertures and form of
epidermal structures,
- are well exposed to atmospheric conditions of light and breeze (i.e. away from
engineering structures hindering free flow of air) to maintain free interaction
with gases.
For the removal of suspended particulate matters, the species of plant to be considered for either
green belt development or reclamation of mining area (Saxena, 2004) should have the following
characteristics:
 height and spread of crown,
 leaves supported on firm petioles,
 abundance of surfaces on bark and foliage, through
- roughness of bark
- epidermal outgrowths on petioles,
- abundance of auxiliary hairs,
- hairs or scales on laminar surfaces,
- stomata protected (by wax, arches/rings hairs, etc.)
It is unrealistic to expect, barring exceptions, that atmosphere in an industrial area will
constitute only of one species of air pollutant. More commonly, one comes across several pollutants,
especially SO2, NOX, oxidants, and SPM in the same region. It will hence be advisable to choose for a
green belt comprising of plant species capable to absorb chemical as well as dust pollutants.
Combined efficiency of a variety of species should contribute to reach the goals of green belts as well
as reclamation of mined land.
A Nursery was set up at GACL HP unit in 1991 to raise plantation before the inception of
cement plant and mines. The species planted mainly fodder, fuel, medicinal and timber were selected
in consultation with forest department.
The stack and fugitive emission control, better environmental management and vegetation
raised in plant and mining area clearly indicates that there is hardly any impact in the vicinity on the
ambient air quality as well as on plantation. In spite of this, few plant species have been selected to
study further the physical and botanical parameters. These species were selected due to their use,
visible growth in the mining area as well as keeping biodiversity and conservation in mind. For this
study, no soil or fertilizer was added. This is mainly to observe the growth in the actual c1onditions.
These plant species include:
- Albizzia lebbek
- Dodonea viscosa
- Jacaranda mimosaefolia
- Leucaena leucocephala
- Nerium indicum
- Populus deltoides
- Prunus puddum
- Toona ciliata
Conclusion
The studies of the effects of air pollutants on plants have often been criticized because they have over-
emphasized the visual symptoms of damage, and have largely consisted of observations made in the
field or under unsophisticated experimental conditions. While there is some justification for this
criticism, there have also been experimental studies of a more rigorous nature that have lead to
important advances in our knowledge of the way air pollutants attack metabolic processes, or affect
the plant's functioning at the physiological level.
The present study reveals that stringent environmental management or sustainable development
certainly helps in pollution reduction. However, there is a need to further study the impact of
Suspended Particulate Matter on selected species mainly for better reclamation of mining area and for
plantation in the vicinity of cement plant.

6. References
1. CMA, 2004: Basic Data - Indian Cement Industry. Cement Manufacturer's Association,
Noida.
2. Saxena Y. K., 1990: A published report on Environmental Management and Control, Gujarat
Ambuja Cements Limited, Kodinar, Gujarat.
3. BDPL, 1991: Comprehensive Environmental Impact Assessment and Environmental
Management Plan for proposed Cement Project at Village Suli, Dist. Solan, HP; Gujarat
Ambuja Cements Limited prepared by M/s Bhagwati Design Pvt. Ltd.
4. Mathur V.S., and Mishra B. K., 1996: An overview on Environment Management in Cement
Industries, Mines Environment and Mineral Conservation. p19-23
5. CPCB, 2000: Guidelines for Developing Green Belts. p 39 - 40. Central Pollution Control
Board, New Delhi
6. Saxena, Y. K., 2002: Study of the Flora and Fauna in Darlaghat and Kashlog Area, Gujarat
Ambuja Cements Limited
7. Saxena, Y.K., 2004: Reclamation of Mined land and Afforestation at Kashlog Mine, Gujarat
Ambuja Cements Limited, Himachal Pradesh.
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7. Figure 1: Manufacturing process of Cement
RAW MATERIAL
CRUSHING
PROPORTIONING AND MIXING OF RAW MATERIAL
GRINDING
KILN KILN DUST
CLINKER COOLER
HOMOGENISING
BLENDING
CLINKER DUST
CLINKER STORAGE
ADDITION OF ADDITIVES
and
FINISH GRINDING
PACKING
TRANSPORATION