Journal of Scientific & Industrial Research

Vol. 62, April 2003, pp 339-343

An Approach Towards the Estimation of Emission Rate from Various Activities of Noamundi Iron Ore Mine - A Case Study

G K Banerjee', K K Srivastava+, M K Chakraborty and M Sundararajan

Central Mining Research Institute, Barwa Road, Dhanbad 826 00 1

Received: 03 June 2002; accepted: 02 September 2002

The major activities of Noamundi iron ore mine in response to serious impact of air pollution in and around the mining area are identified. A mathematical model is developed to estimate the emission rates from various activities or sources. The present model is developed based on the Pasquill-Gifford formula. Detailed studies over processing plant operations, geology, meteorology of the study area are carried out in order to prepare the emission inventory of the open cast mining activity through estimating the emission rates of the significant activities, using the present mathematical model. A few recommendations on the basis of the results of the study are also given.

Introduction

Air pollution problems vary widely with respect to area and pollutant's behaviour. The particulate matters from the iron ore mine can cause serious health hazards among the mine workers as well as the inhabitants of the area. S ize fraction is the most important factor to cause serious impact on the health. The thoracic particle (aerodynamic diam less than I O/-1; PMIO) and of fine particles (aerodynamic diam less than 2.5 /-1; PM2 5) are very significant fractions of these kinds 1 -4. The unsystematic and unplanned disposal of flaky ore and blue dust may pose an immense problem in and around the mining5,6.

A study on open cast mining reports that about 50 per cent of the total coal dust is lost while the dumpers move on unpaved haul roads and 25 per cent for both during loading and unloading of dumpers. Atmospheric particles have a direct impact on c l imate. As the world statistics has shown that open cast mining methods are the easiest, quickest and cost- effective and safe for increasing mineral output, it has long been fel t by the industries to study the emission factors of different mining operations of the open cast mines in order to promote the mining industries 7 .

• Author for correspondence Email : goulam_kb@ sify.com

+ Director, Higher Education of lharkhand, Ranchi

Therefore, it is needed to develop a method to estimate the actual emission rate of air quality parameters at the s i te of mining operation for different activities. In this connection the emission rates of air parameters from various nunmg operations have been estimated through an innovative approach.

Materials and Methods

The study area, geology, meteorology, method of sampling and the approach for emission estimation of air quality parameters from various activities or sources have been described in detai l .

Study Area

Noamundi iron ore mine is s i tuated around 220 . 0 '

9 N latitude and 85 29 E longitude on the eastern edge of Saranda forest in the d istrict of West Singhbhum in Jharkhand bordering Keonjhor district of Orissa State. This is one of the oldest and l argest open cast projects of iron ore mines in the country. The study area is shown in Figure 1 . The mine at Noamundi is the principal source of i ron ore for steel works located at J amshedpur. It i s s ituated 1 26km by rail from Jamshedpur in the West Western part of S ingbhum d istrict in Jharkhand State. The iron ore bearing deposits of the region belong to the iron-rich series of Dharwarian age. It consists, mainly of two parallel ridges, each about 2 km long and 0.8 km

340 J SCI IND RES VOL 62 APRIL 2003

� '?>.'1f1jr; ro:...�(i � 'Bet: c(·nveyor

Figure I - Showing the location map of Noamundi iron ore mining area i ncluding the area of ore processing unit

wide, separated by a valley. Four principal types of predominantly hematic ores occur in this area, i .e . , hard ore, soft ore, friable flaky ore and blue dust. The total reserve is around 200 Mts, of which, nearly half is blue dust and flaky ore. The overburden is very thin and marginal, but patches of was1i.e rock occurrences are encountered within the deposit. The mine is essential ly a h i l ltop operation and there i s no problem of water accumulation. The depl)sit has been ful ly proved by sub-grid pattern diamond dril ling. The primary crusher is located at 600m level , fol lowed by surge-pi les, secondary crusher, wash plant, fin ished product stockpile, and then 5 km long belt conveyor and loading plant for d ispatch ing the ore by rai l wagons to Jamshedpur.

Geology

The formation containing iron ore deposits belongs to the late Archean iror ore series. These deposits have been formed under marine conditions. The origin of iron seems to be weathering of continental rocks under reducing atmospheric conditions which were prevalen : during the early Archean age. It consists of undulating surface with steep to gentle s lope and reddish yell ow to chocolate colour soi l . Reserve forests exist i l l the area. Few jors are located within the leasehold aF!a.

Meteorology

The cl imate of the area i s dry tropical . There are four seasons during the year, i .e., ( i) Summer season (March to May), ( i i ) Rainy season (June to September), ( i i i ) Autumn season (October to Noverber), and ( iv) Winter season (December to

February). During summer months temperature goes up to 47° C and in winter it fal ls to as low as 1 0° C . Annual mean maximum and minimum temperatures )( .

are 33.2° C and 20.5° C respectively . The wind speed (kmlh) and direction were monitored during winter season in order to find the maximum impact of air qualities and its average value was calculated for three significant ranges in al l direction. It was observed during the study that the prevail ing wind direction at that t ime was northwest.

Mining Activities or Sources

Several numng activities or sources are considered to study the emission estimation in open cast mining. These activi ties or sources may be categorized as point, l i ne, and area sources. The mining activi ties l i ke dril l ing, overburden loading and unloading, coal handling and sources l i ke haul road transport road, exposed pit surface, and overburden dumps, stockyards and workshops are considered for the present study.

Sampling Technique and Analysis

The standard h igh volume air sampler was used for monitoring SPM, S02, and NO. measurement with gaseous sampling arrangement. The average flow rate was between 1 . 1 m3/min and 1 .3m3/min during the sampling at proposed monitoring stations. The air samplers were kept at a height of 6 m above the ground level to avoid the dust from ground source. According to USEPA guidel ines, 24h sampling was done for SPM and the fi lter paper was replaced in each 8h interval with gaseous sampling unit for sampling S02 and NO • . Using WHATMAN GF A glass microfibre filter papers the samples of SPM were collected. The filter paper was kept in a dis iccator for 24 h to remove the moisture content and it was weighed before sampling (WI g). The filter paper was dried again after sampling by using the same method for 24 h and weighed without folding (W2 g). The samples of S02 and NO. were observed, using sodium tetrach loromercurate and sodium hydroxide solution, respectively. The SPM were analyzed by gravemetric method and S02 and NO, analyzed calorimetrically, by using spectrophoto­meter, according to the standard methods.

The air pollution concentration was measured at three points at each source site to estimate the emission rate of the each source or mining activity . The sampler- l was kept in upwind direction and

BANERJEE et at. : ESTI M ATION OF EMISSION RATE OF NOAM UNDI IRON ORE MINE 34 1

sampler-2 and sampler-3 in the downwind direction so that the samplers and the source would l ie in wind axis, as shown in Figure 2. The distance scheme between high volume samplers and the source may be kept as d l -d2=d2+d3 to detect the upwind source emission in order to avoid the distance factors in the emission calculation.

Approach for Emission Estimation

The fol lowing equation is used to estimate the concentration from the source at known distance, excluding the upwind source:

c = C _( C1C3 )( dl - d2 ) X.II 2 C d + d 2 2 3

The emission rate of different mining activities was estimated on the basis of modified Pasqui l l and Gifford formula for ground level sources. The equation is as fol lows.

where ex. 0 is the concentration of SPM from the source subtracting the upwind concentrations (g/m'), Q i s emission rate of the pollutant species (g/s), u is average wind speed (mls) , and cry and crz are the horizontal and vertical dispersion coefficients, respectively, compiled as functions of downwind distance (m).

Emission Inventory

There are twelve significant sources or activities in Noamundi iron ore mines. The emission rate of different mining source or activity is calculated and presented in Table 1 . The concentrations of oxide of nitrogen and sulphur dioxide are quite low in comparison to suspended pmticulate matter. Therefore, oxide of nitrogen and sulphur dioxide are

He. -DR He, bt �d3 ---"

04 d1 � �d 2 -----'

Figure 2 - Sampling technique of air quality parametres in and around mining area

calculated as whole mine. On the other hand, suspended particulate matter is also calculated as a whole mine. The calculated emission rates of suspended particulate matter, oxide of n itrogen and sulphur dioxide for whole mine are presented in Table 2 .

Validation

The present mathematical model is developed theoretically and is supported by the well known Pasqui l l and Gifford equation.

Results and Discussion

The results show that the activities, l ike dri l ling, loading, and unloading of overburden dump materials and the sources l ike haul roads and transport roads contribute to the SPM concentration considerably among all activities of open cast mining. It has also been concluded from various studies that vehicular traffics on haul roads of mechanized open cast mines are the most prolific source of fugitive dust and contribute up to 80 per cent of the dust emitted from a surface coal mine8,9. It has been found that the SPM emissions from OB unloading, hau l road and transport road are around 0.9587 gis, 0.908 1 glslm, and 0.8397 glslm, from iron ore mine. The emission rate from the screening plant is 0.00043 1 g/s/m2 from iron ore processing plants . Also the emission rates from OB loading and mineral loading are 0.4796 gls and 0.3793 gls from iron ore mine, respectively.

It has been observed that the emission rates of SPM, S02, and NOx from overal l iron ore mine are : 4 .5489 gis, 0.0390 gis, and 0.47 1 6 gis, respectively. Though the air quality emissions from iron ore mine are significantly less than the coal mines, the SPM emission from iron ore mine may cause very serious health hazards in and around the mining areas . As they are the most insidious pollutants because of their non-biodegradable nature and property to affect al l forms of the ecological system. Air qual ity dispersion study in and around Noamundi iron ore mine, which is one of the study areas has been carried out and i t has been reported that the concentration level around the residential areas is about 20 Ilg/m3. 1O . The emission rate of SPM due to various mining activities is shown in Table I . The emission rates of the parameters, l ike S02 and NOx are not shown for different operations because the emissions of these parameters are negligible. Therefore the emission rates for the parameters S02 and NOx for a whole

342 J SCI IND RES VOL 62 APRIL 2003

Table l - Emis ,ion inventory for different mining activity at Noamundi iron ore mine

Activity

Dri l ling

OB loading

M ineral loading

Haul road

Transport road

OB unloading

Mineral unloading

Exposed OB dump

Stockyard

Screening plant

Workshop

Exposed pit surface

SPM

SPM

SPM

SPM

SPM

SPM

SPM

SPM

SPM

SPM

SPM

SPM

Upwin d

C 1

782

760

809

954

748

945

780

793

7 1 5

765

638

488

SPM concentration (l1g/m3)

Downwind Downwind d d

(Max) C2 (Min) C3

1 270

1 284

1 458

1 836

1 480

1 432

1 472

1 1 05

1 243

1 379

1 056

8 1 5

1 029

892

1 0 1 1

1 544

1 252

1 1 68

1 072

935

874

963

892

560

Cx • . ,

637

757

898

1 032

852

662

904

434

741

845

5 1 8

473

Wind speed u (mls)

2.0

1 .8

1 .2

2.5

2.8

1 .2

2.2

1 .2

2.9

2.0

1 .5

2.0

Dispersion . coefficient

Oy Oz (m) (m)

1 4

1 4

1 4

1 4

1 4

24

1 4

1 5

1 4

1 4

25

1 8

8

8

8

8

8

1 6

8

3 2

8

8

1 5

8

Emission rate

Unit Value

g/s

g/s

g/s

g/s/m

g/s/m .

g/s

g/s

g/s/m2

g/s/m2

g/s/m2

g/s/m2

g/s/m2

0.4484

. 0.4796

0.3793

0.908 1

0.8397

0.9587

0.7000

0.0000282

0.000 1 58

0.00043 1

0.0000737

0.0000 1 88

Table2 - Emission inventory for whole mines at Noamundi iron ore mine

Activity

Overall mine

Overal l mine

Overall mine

SPM

S02

NOx

Upwind C1

275

1 8

42

. 1 S P M concentration (l1g/m' )

Downwind (Max) C2

508

1 7

66

Downwind (Min) C3

379

. 1 3

59

mine have been computed . The emission rates of SPM, S02 and NO, due to the whole mining activities are l isted in Table 2 .

Conclusions and Recommendations

On the basis of studies carried out in and around the iron ore mines the fol lowing points are highl ighted with few recommendat ions :

( i ) SPM is the major pollution in and around the iron ore open cast mine. The OB unloading, haul roads and the transport roads are the significant sources among all other sources l ike mineral unloading, on loading, dri l ling, mineral loading, exposed OB dumps, stock yard, workshop, exposed pit surface and screening plant activities. It i s necessary to

. Cx • .,

303

4

29

Wind speed u (mls)

2.3

2.3

2.3

Dispersion coefficient

Oy Oz (m) (m)

60

60

60

45

45

45

Emission rate

Unit Value

g/s

g/s

g/s

4.5489

0.0390

0.47 1 6

sprinkle water along the haul roads and transport roads of the mining area and also to unloading material to suppress the particulate matters of the aerodynamic having diam less than 1 0 �.

(ii) It IS recommended that the loaded dump materials should be packed properly and made more compact using bigger size material on the top to arrest the fine partic les so that the wind may not enter inside and spread them into atmosphere.

(iii) Certain evergreen plants, grasses, and epiphytes l ike orchids could control the concentration of SPM. A study has reported that certain plants have remarkable dust filtering, air c leaning, and air purifying

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J.

. B ANERJEE et al. : ESTIMATION OF EMISSION RATE OF NOAMUNDI IRON ORE MINE 343

capacIties. The plants with simple leaves, . such as Peepal (Ficus benghaiensis), Mast (Polualthia), Mango (Mangi ferg indica), Teak (Tectong . grandis), Sal (Shoreg robusta), and Arjuna (Terminalis arjuna) are ' better dust col lectors than the plants with compound leaves l ike gulmohar, tamarind, . d ' I . d 7 1 1 cassia IStu a, an neem ' .

( iv) The plantation of local species over the peripheral area of proposed overburden dump disposal site should be done, before the commencement of the project in order to . control the dust emission during unloading of the dump materials.

(v) Screening plant and all ied process account for a significant amount of total dust produced in mining and i ndustrial areas. Main dust generating operations in screening plant are unloading at bunker, crushing, screening and multistage conveyor transfer points: Therefore, an effective and economic air pollution control system using canopy curtain method for absolute dust control at these dust generating points must be developed by assimilating the features of both dry and wet systems.

Acknowledgement

The authors are grateful to Noamundi Iron Ore Mine for the financial assistance and support. Thanks are also due to the colleagues who · supported at various stages of the analysis. The authors are thankful to Director, Central M ining Research Institute, Dhanbad for his kind permission to publish this paper.

References · I Schwartz J L, Particulate air pollution and chronic

respiratory disease, Environ Res, 62 ( 1 993) 7- 1 3 .

2 Pope A & Dockery D W, Acute health effects of PM pollution on symptomatic and asympotic children, Am Rev Respir Dis, 145 ( 1 992) 1 1 23- 1 1 28.

3 Dockery D W, . Pope C A, Xu X, Spengler J D, Ware J H , Fay M E, Ferris B G & Speizer F E, An association between air pollution and mortality in six US cities, New Eng J Med, 329 ( 1 993) 1 753- 1 759.

4 Seaton A, MacNee W , Donaldson K & Godden D, Particulate air pollution and acute health effects, Lancer, 345 ( 1 995) 1 76- 1 78.

5 Cowherd C (Jr) Bohn R & Cascino T, Iron and steeL pLant open source fugitive emission evaLution, Report No. EPA-600/2-79- 1 03, U S Environmental Protection Agency, Research Triangle Park, NC, 1 979.

6 Pilegard K , Air born metals and sulpher dioxide monitored by epithic Lichens in an industrial area, Environ Poilut, 17 ( 1 978) 82-92.

7 Sinha S , Quantification of fugitive particle emission from line source in surface coal mine - An approach, Indian J Environ Protect, 15 (5) ( 1 995) 339-343.

8 Sinha Subrato & Banerjee S P, Characterization of Haul road dust in an Indian open cast iron ore mine, A tmos Environ, 31 (No. 1 7) ( 1 997) 2809-28 1 4.

9 Axetell K & Cowherd C, Improved emission factor for fugitive dust from western surface coal mining source, Emission Factors Project Summary of EPA, 11 ( 1 98 1 ) 68-03-2924, (U.S Environmental Protection Agency, Cincinnati, Ohio, PED Co Inc., Kansas City, Midwest Research I nstitute).

1 0 Sundararajan M , Banerjee G K Kumar Nikhil & Misra D D, Air quality dispersion scenario at Noamundi iron ore mine through mathematical modeling and computer simulation -A case study, Nat Symp Sustain Min Technol: Present Fut (SMINTECH-2002), Anna University, Chennai (March 2002) 322-33 1 .

I I Banerjee G K, Srivastava K K & Chakraborty M K , SPM is major pollution in opencast mining - A case study, J Sci Ind Res, 60 (200 I ) 4 1 6-420.