Standardized Emissions Inventory Methodology mining 234

RESEARCH ARTICLE

Standardized emissions inventory methodologyfor open-pit mining areas

Jose I. Huertas & Dumar A. Camacho & Maria E. Huertas

Received: 17 September 2011 /Accepted: 20 January 2012 /Published online: 10 February 2012# Springer-Verlag 2012

AbstractIntroduction There is still interest in a unified methodologyto quantify the mass of particulate material emitted into theatmosphere by activities inherent to open-pit mining. For thecase of total suspended particles (TSP), the current practiceis to estimate such emissions by developing inventoriesbased on the emission factors recommended by the USEPAfor this purpose. However, there are disputes over the specificemission factors that must be used for each activity and theapplicability of such factors to cases quite different to the onesunder which they were obtained. There is also a need forparticulate matter with an aerodynamic diameter less than10 m (PM10) emission inventories and for metrics to evaluatethe emission control programs implemented by open-pit mines.Standardized emission inventory methodology To addressthese needs, work was carried out to establish a standardizedTSP and PM10 emission inventory methodology for open-pitmining areas. The proposed methodology was applied toseven of the eight mining companies operating in the northernpart of Colombia, home to the one of the worlds largest open-pit coal mining operations (70 Mt/year).

Results The results obtained show that transport on unpavedroads is the mining activity that generates most of theemissions and that the total emissions may be reduced upto 72% by spraying water on the unpaved roads. Performancemetrics were defined for the emission control programs imple-mented by mining companies. It was found that coal open-pitmines are emitting 0.726 and 0.180 kg of TSP and PM10,respectively, per ton of coal produced. It was also found thatthese mines are using on average 1.148 m2 of land per ton ofcoal produced per year.

Keywords Emissions inventory . Open-pit or open-castmining . TSP. PM10

1 Introduction

Currently the open-pit coal mining activities underway in north-ern Colombia are regarded as the world's largest coal miningzone with more than 70 Mt/year. Colombia is the number 12country in the list of the largest coal producer countries in theworld (Energy Watch Group 2007) and second with the largestcoal reserves among the LatinAmerican countries (BP 2009).

Given the economic impact of the open-pit mining on theregions where it takes place, the environmental authoritiespromote this activity while also limiting its environmentalimpact. Particulate matter is the main air pollutant in miningregions. It has important implications in cloud formation,radiation budget, and multiphase processes (Zhang et al.2008; Zheng et al. 2011). TSP and PM10 in open-pit miningregions reduce visibility and affect surrounding floraand fauna. Additionally, they can cause black lung(CWP), silicosis, and increased mortality (Wheeler etal. 2000; NIOSH 2005).

In some cases, even though the mining companieshave adopted the control measures recommended by the

Responsible editor: Philippe Garrigues

D. A. CamachoTecnolgico de Monterrey,Eduardo Monroy Crdenas No 2000,Toluca, Mexico

M. E. HuertasTexas A&M University,College Station, TX 77843, USA

Present Address:J. I. Huertas (*)Tecnolgico de Monterrey,Eduardo Monroy Crdenas No 2000,Toluca, Mexicoe-mail: [email protected]

Environ Sci Pollut Res (2012) 19:27842794DOI 10.1007/s11356-012-0778-3

environmental authorities, the problem of air pollutedwith particulate matter in the population centers locatednearby the mining zones still persists. With time, thisproblem continues to worsen as the production rate ofthe mines increases. Open-pit coal mines increased theirannual production from 5 Mt in 2000 to 70 Mt in 2010.

The first step in looking at potential solutions to the airpollution problem is to quantify the mass of pollutants thatis being emitted into the atmosphere.

In an open-pit mine co-exist fixed (e.g., power plants),mobile (e.g., trucks, bulldozers, etc.), and fugitive (e.g.,loading and unloading of material) sources of emissions. Ithas been found that particulate matter from no combustionsources is by far the main pollutant generated in an open-pitmine (Ghose and Majee 2000, 2001).

Unlike fixed and mobile sources, fugitive dust emissionsfrom the mining operations cannot be measured. The currentpractice is to estimate such emissions by developingemissions inventories based on emission factors.

Axetell (1978), Axetell and Cowherd (1981), Cowherd(1982), Missouri Department of Natural Resources (2009),Muleski (1990, 1994), Shearer et al. (1981), Thompson andVisser (2003), US Department of Energy (1980), USEPA(1998, 2006a, b, 2008) and Zeller et al. (1979) have derivedexperimentally emissions factors for the case of individualactivities involved in open-pit coal mining. The validity ofthese emission factors is limited to the conditions underwhich they were obtained.

Ghose (2004, 2007) based on their own emission factorsestimated that a typical open-pit coal mine in India with astripping ratio of 3.98 emitted 9,366.7 kg/day of TSP while itsproduction was 2,500 t/day, i.e., 3.74 kg of TSP per ton of coalproduced. The mine companies operating in Colombia havealso estimated their TSP emissions following their own meth-odologies but they have not published them. The Aus-tralian government (2011) has established a simplifiedmethodology to estimate pollutants inventories. However,they have not made available any results yet.

The TSP emission inventories so far made differ in theemission factors used for each activity and in the activitiesconsidered which leads to large differences in the resultsobtained. Additionally, the emission factors used in thosestudies do not take into account the particular conditions ofthe region in terms of soil composition and the weatherconditions inherent to a semi-arid tropical region. Finally,there is not any study related to PM10 emissions for open-pitmining. Currently, environmental authorities are more inter-ested in PM10 emission rather than TSP emissions given thatPM10 are more harmful to human health than TSP. There is,consequently, a need for a standard or unified methodologyto conduct the emission inventories for TSP and PM10.

Work was conducted to develop a standard methodology toestimate TSP and PM10 emissions for the case of open-pit

mining operations along with several alternatives to assess thevalidity of its results. As a result, three metrics are proposed toevaluate the performance of the emissions control programsimplemented in open-pit mines. Themethodology was appliedto seven of the eight open-pit coal mining companies operatingin Colombia. A description of the methodology and the resultsobtained after its application are reported in the present paper.

Additionally, the precision and accuracy of those emis-sions inventories were evaluated following a backward airquality simulation approach (Huertas et al. 2012a). Theresults of the emissions inventories were incorporated intothe ISC and AERMOD air quality models to assess theenvironmental impact of the open-pit mining activitiesaround the region where they operate (Huertas et al.2012b). Airborne samples from the mining region wereanalyzed to obtain TSP and PM10 concentrations, particlemorphology, particle size distribution and elemental composi-tion of the particles (Huertas et al. 2012c). Finally, the partic-ulate material dispersion and the sedimentation processesinside an open-pit mine were modeled using previous resultsand computational fluid dynamics in order to look into newemission control alternatives. The results obtained in this lastwork are reported in Huertas and Vilchis (2011).

As a result of the whole work, new emission controlmeasures were identified. For the case of Colombia, someof these measures are being implemented under the guid-ance of the Colombian environmental authorities.

2 Standardized emission inventory methodology

The processes involved in open-pit mining and the differentextraction technologies used by several companies werestudied. It was observed that open-pit mining involves thefollowing general processes:

& Removal of the vegetable layer (top soil)& Removal of overburden& Removal of the useful geological material

Each one of these mining operations is, in turn, dividedinto various different activities, that depend on the technol-ogies used. Each activity is an emission source. Appendix Alists these activities.

Current methodologies to estimate the mass of TSP orPM10 (Ei), that is released into the atmosphere by activity i,are based on emission factors. The emission factor for eachactivity i (Ef,i) has been obtained by means of the followinggeneral, empirical equation (USEPA 2009).

Ef ;i a Sba M gp M zc : 1

Where Sa, Mp, and Mc are variables that characterize theemitting activity, material's properties, and meteorological

Environ Sci Pollut Res (2012) 19:27842794 2785

conditions, respectively. , , , and are experimentalconstants that depend on each activity and are reported inAppendix A. The mass of particulate matter emitted duringactivity i (Ei) is estimated as (USEPA 2009):

Ei Ai Ef ;iY

1 j

: 2

Where Ai is the intensity of activity i and j is theefficiency of the emission control measure j implementedfor activity i.

For the case of open-pit coal mining operations, the TSPand PM10 emission factors reported by the USEPA wereobtained through various experimental studies carried outin mining areas in USA by the Western Institute (Axetell1978; Axetell and Cowherd 1981; Muleski 1990, 1994;Shearer et al. 1981; US Department of Energy 1980;USEPA 2008). However these sources of information onlyhave emission factors for some of the sub-activities involvedin the open-pit mining.

Here, it is proposed to use these emission factors as theywere originally established until local experimental studies canbe made in order to adapt them to the local conditions. Fur-thermore, it is proposed to adopt the emissions factors reportedin references USEPA (2006a, b) and Missouri Department ofNatural Resources (2009) for the activities not included in theprevious references such as wind erosion, handling, and stor-age in piles and transportation over unpaved roads.Appendix A lists and classifies all these emission factors.

2.1 Special considerations

Emission factors for loading and unloading of materialsFor the case of loading and unloading of soil, overburden,and the useful geological material, it was used the emissionfactor (Ef,l) reported by the (USEPA 2006b) for aggregatehandling and storage in piles of granulated material

Ef ;l a U=2:2 1:3

M=2:0 1:4 3

Where U is the mean wind speed, M is the material'smoisture content, and is a constant equal to 0.0012 forTSP and 0.00056 for PM10. Equation 3 is valid for materialswith silt content between 0.44% and 19%, material's mois-ture content between 0.25% and 4.8% and wind speedconditions between 0.6 and 6.7 m/s. However most of theapplications in open-pit mining are outside these ranges.Figure 1 shows for the case of TSP the behavior of Eq. 3in these ranges of validity.

Given the difficulty of obtaining this emission factor forranges outside of those specified above, it is proposed to usethis emission factor under the conditions representing theworst-case scenario. That is, the value of 4.8 will be used in

Eq. 3 for applications where the material moisture contentexceeds 4.8%. If the wind speed is greater than 6.7 m/s, theactual wind speed value will be used in Eq. 3.

Emission control measures Various emission control techni-ques have been developed for the transportation of cargo onunpaved roads. All of them are based on spraying water on theroads, with or without additives. Cowherd 1988 estimated theefficiency of emission control by spraying water (s) withoutadditives by means of the following equation:

s 10:8 p r t

k

4

Where p is the average daytime evaporation rate, r is theaverage daily traffic, k is the intensity of the applications inliters per meter squared, and t is the average time betweenspray applications.

Additionally, USEPA (2006a) estimated the efficiency ofparticulate matter emission control (r) through naturalspraying (rain) by means of the following equation:

r 1m nm

5

Where m is the number of days in the period and n is thenumber of rainy days in the period with precipitation levelsexceeding 0.254 mm.

Since water availability is always an issue during dryseasons, mine companies are continuously looking for newtechnologies to increase emission control efficiencies mini-mizing water usage and cost. Available technologies arebased on water additives that reduce water evaporation andmaintain particular matter agglomerated over the unpavedroads. Table 1 lists and compares these types of technolo-gies. Additional work is required to quantify the actualefficiencies of these technologies by on site tests.

0.6 1

.8 3.0 4

.2 5.4 6

.6

0.00

0.02

0.04

0.06

0.08

0.10

0.25

1.00

1.75

2.50

3.25

4.00

4.75

Emiss

ion

fact

or (k

g TSP

/Mg)

Fig. 1 TSP emission factor for loading and unloading processes asfunction of material's moisture content and wind speed

2786 Environ Sci Pollut Res (2012) 19:27842794

2.2 Implementation of the methodology on a spreadsheet

In order to standardize and facilitate the development of TSPand PM10 emission inventories, Eqs. 1 to 5 were implementedon a spreadsheet for all of the activities involved in the open-pitmining operation. For the sake of convenience, the resultsobtained were grouped into the following operations: soil han-dling operations, drilling and blasting, handling overburden,handling coal, wind erosion, and transportation. Appendix Alists the operations and activities considered.

Since emission inventories expressed by areas are re-quired as input data for air quality models, the resultsobtained were regrouped by the location of the sources inthe following physical areas: pit, dumps, coal storage piles,and roads. The routes considered were: from the pit to thedump, from the pit to the storage piles, and from the storagepiles to the mine limits. Appendix A shows how thisregrouping was made.

It was found that the volume of information required tocomplete the emissions inventory is high and, in some cases,

mining companies do not have all this information available.In the cases of non-critical information, algorithms thatmake possible to estimate this missing information wereincorporated by using historical records and experimentalreadings obtained from alternate sources, such as averagemeteorological conditions, soil characterization, etc.

Additionally, algorithms to alert the user about potentialerrors in the emission inventory input data were incorporatedinto this spreadsheet. This was done through statistical iden-tification of non typical values. That is, data that is outside ofthe confidence interval with a level of confidence of 95%(Devore 2008). Finally, shielding tools were incorporated intothe spreadsheet that allows the environmental authority toensure that the emission inventories made by the miningcompanies follow the same procedures and the samecalculation methodology. It also incorporated the feedbackof several coal mining companies, environmental authorities,and private consulting firms in a process that lasted almost2 years. Finally, a manual was written to assist the users in theemission inventory preparation process.

Table 1 Technologies to control particle emission from unpaved roads

Working mechanisms Advantages Disadvantages Products

Water Wets the particles increasing theirmass and agglomerating them

Low cost, easy to apply It requires regular applications N/AMinimum environmental impact Overwatering cause deterioration of

roads and operational problems

Salts Hydroscopic substance Reduce evaporation to 1/3 It is corrosive RoadmagAttract and retain soil moisture It compacts the material

of the roadDisappear with rain

It does not disappear with withthe maintenance of the road

Have environmental impact (ions)

Surfactants Reduce surface tension of water Easy to apply and flexible Low residual effects Drimax 1235

Perma-Zyme

RT9

Durasoil

Resin emulsions Act as adhesive substances Low solubility Disappear with the maintenanceof the road

Pavcryl

Agglomerates the fineparticles of the road

Non corrosive Limited to heavy use Alcotac DS1

Seals the surface against water Soiltac

Lignin derivates Act as adhesive substances No water requirement Disappear with the rain Perma-Zyme

Agglomerates the fine particlesof the road

It does not disappear with themaintenance of the road

Slippery when it is wet Alcotac DS7

Have environmental impact (ODB) Durasoil

Bitumens Agglomerates the fine particlesof the road

Insoluble in water applications Highly costly impact (HCs) Dust-a-side

Pave the road Seals the surface against water Have environmental Jegel

Appropriate for long-term Dust stop

SLS

Used oil

Polymers Act as adhesive substances More effective agglomerationthan resins

Require regular applications RT9

Agglomerates the fine particlesof the road

Appropriate for long-termapplications

Low environmental impact


3 Results

As an example of its applicability, the standardized emissionsinventory methodology for open-pit mining was applied toseven of the eight open-pit coal mine companies operating inthe north part of Colombia for the years 2007, 2008, and 2009.The coal mines operational parameters were provided directlyby each company. The following analyses were made in orderto assess the validity of the emission inventories obtainedthrough the standardized methodology.

3.1 Comparison of the operational parameters reportedby coal mining companies

Statistical analysis of the data reported by the mine compa-nies was performed to identify non typical values. Thesevalues were double checked with the respective companies.Table 2 reports the average values of the mines operationalparameters reported by the companies.

3.2 Comparison by total emissions

Figure 2a, b shows the kilogram of TSP and PM10 (respec-tively) emitted per ton of annual coal production. It obtaineda high value for the coefficient of determination (R200.909for TSP and R200.849 for PM10) in the linear correlationanalysis between these two variables indicating that there isa high linear correlation between particulate matter emis-sions and mining production. It was also found that onaverage, a mine company generates 0.726 kg of TSP and

Table 2 Main operational parameters of open-pit coal mining

Description Units Average Min Max Standard deviation n

Physical properties Density Topsoil t/m3 1.83 1.20 2.40 0.35 20

Overburden t/m3 2.41 2.10 3.00 0.17 20

Coal t/m3 1.30 1.25 1.30 0.01 16

Silt content Topsoil % 10.7 2.0 30.0 11.6 16

Overburden % 5.5 2.0 20.0 4.2 16

Coal % 4.3 1.7 10.0 1.8 16

Moisture content Topsoil % 12.5 6.0 15.0 3.5 16

Overburden % 8.8 2.9 12.0 2.6 16

Coal % 10.2 6.0 13.0 2.8 16

Operational parameters Overburden to carbon ratio mg/mg 15.1 5.5 35.2 9.20 16

Topsoil to carbon ratio mg/mg 0.26 0.00 3.41 0.84 16

Land use Overburden Pit and dump Ha 297.7 2.5 1569.3 369.4 16

Coal Stock Ha 11.7 2.0 36.2 9.0 16

Meteorology Days with precipitation >0.254 mm days/period 102.2 2.0 152.0 44.4 16

Evaporation rate mm/h 1.30 0.04 4.50 1.61 16

Average wind speed m/s 1.58 1.19 1.89 0.24 16

% of wind speed >5.33 m/s % 4.2 0.0 50.0 12.2 16

y = 0.726x + 31084R = 0.909

0.0E+002.0E+064.0E+066.0E+068.0E+061.0E+071.2E+071.4E+071.6E+07

0.E+00 5.E+06 1.E+07 2.E+07 2.E+07

Kg

TSP

/yea

r

Production (Mg/year)

4

6

7

351

2

y = 0.180x + 83540R = 0.849

0.0E+005.0E+051.0E+061.5E+062.0E+062.5E+063.0E+063.5E+064.0E+06

0.E+00 5.E+06 1.E+07 2.E+07 2.E+07

Kg

PM10

/yea

r


2

4

7

5

3

a

b

Fig. 2 a kilogram of TSP emitted per ton of coal produced by sevenopen-pit coal mines in Colombia during 2009 as function of theirannual production. b kilogram of PM10 emitted per ton of coal pro-duced by seven open-pit mines in Colombia during 2009 as function oftheir annual production


0.180 kg of PM10 (respectively) per ton of coal produced.For the case of India, Ghose (1989, 2007) reported a valuefor this metric of 3.74 kg/t for an open-pit coal mine with astripping ratio of 3.98. This reference does not mention theuse of any emission control measure. Here, it is proposedthe ratios of TSP and PM10 to the annual production as thefirst metrics to evaluate the performance of the emissioncontrol programs implemented by the open-pit miningcompanies.

Figure 3 shows the total area used by each coal companyin the mining process as function of its annual production.As in the previous case, this figure shows that there is a highlinear correlation between these two variables (R200.945)and that on average mining companies use 1.148 m2 forevery ton of coal produced per year. This ratio assesses landuse. It evaluates the extension of the areas exposed to winderosion, length of unpaved roads used for transportation,size of the pit area and the extension of land used for coalhandling and storage. This parameter corresponds to thesecond metric to evaluate the performance of the emissioncontrol programs implemented by the open-pit miningcompanies.

3.3 Comparison of emissions by mining activities

Figure 4a, b shows the contribution of each general activityto the emissions of TSP and PM10, respectively. Cowherd(1988) estimated that 50% of the total TSP is emitted duringthe transportation of material over unpaved roads within themine. Here, it was found that by spraying water over theseunpaved roads, companies have been able to reduce TSPemissions by 72%, on average. Companies reported thatthey spray water between 1 and 2 l/m2 between two andfour times every hour and that they obtain 99% of efficiencyin controlling particulate matter emission according to Eq. 4.Further work is required to validate the applicability of Eq. 4to the local conditions and to establish the appropriatespraying parameters to minimize water use.

Figure 4a shows that on average, transportation overunpaved roads still represent the largest emission sourcewith a 34% of contribution to the total emissions of TSP.It is followed by coal handling and wind erosion with acontribution of 29% and 28%, respectively. This resultagrees with Chaulya (2004, 2005) who reported thatmaterial handling and wind erosion are the other twomain sources of TSP.

For the case of PM10, the contributions to the totalemissions are quite different. On average, 52% of thePM10 emissions are due to overburden handling, 25% totransportation, and 16% to coal handling as it is shown inFig. 4b.

3.4 Comparison of emissions by area source

As it was mentioned previously, emissions were rear-ranged by the location of the sources as indicated inAppendix A. Results for the seven companies wereaveraged. Figure 5a, b shows the average of the contri-bution of each area being considered to the total emis-sion of TSP and PM10, respectively. Figure 5a showsthat pits and dumps are the main area sources of

y = 1.148x + 33515R = 0.945

0.0E+0

5.0E+6

1.0E+7

1.5E+7

2.0E+7

2.5E+7

0.0E+0 5.0E+6 1.0E+7 1.5E+7 2.0E+7

Are

a (m

2 )


Fig. 3 Total area used by companies in the open-pit mining process asfunction of its annual production

0%10%20%30%40%50%60%70%80%90%

100%

1 2 3 4 5 6 7

Con

trib

utio

n to

T

SPem

issio

ns

Mining company

Wind erosionTransportationCoal handlingOverburden handlingDrilling and blastingTopsoil removal

0%10%20%30%40%50%60%70%80%90%

100%

1 2 3 4 5 6 7

Co

ntr

ibut

ion

to PM

10em

issio

ns

Mining company

Wind erosionTransportationCoal handlingOverburden handlingDrilling and blastingTopsoil removal

a

b

Fig. 4 a Contribution to TSP emissions of the activities involved inopen-pit mining for the case of coal production in Colombia during2009. b Contribution to PM10 emissions of the activities involvedin open-pit mining for the case of coal production in Colombiaduring 2009


emissions with an average contribution of 42% and 18%to the total emissions of TSP, respectively.

Similarly, Fig. 5b shows that the dumps and the pits arethe main area sources of PM10 emissions with a contributionof 60% and 16%, respectively.

Emissions from dumps are of greater concern since theyare located at the highest point of the mine and thereforehave the potential of being transported by wind action forthe longest distance outside of the mine. Even though emis-sions from pits are important in quantity, a high percentageof them remain within the pit due to air recirculation withinthe mine (Silvester et al. 2009; Huertas and Vilchis 2011).

4 Recommendations

It is recommended to establish the following metrics toevaluate the performance of the emission control programsimplemented by open-pit mining companies.

Emission index It is defined as the total mass of particulatematter emitted to the atmosphere, estimated through anemission inventory, and divided by the company's annual

production. This index can be reduced, for example, bywatering areas exposed to wind erosion, avoiding ma-terial transportation on unpaved roads (use of trainsand conveyors), generating barriers to wind circulationaround piles and coal grinders, increasing moisture content ofcoal and overburden etc. For the case of coal mining inColombia this metric has a value of 0.726 and 0.180 kg/t forTSP and PM10, respectively.

Land use index Defined as the total area exposed to windaction, length of unpaved routes, pit areas, and dump areasetc. divided by the company's annual production. Minecompanies can reduce this metric by minimizing routelengths and by reducing uncovered areas used as dumpsand pits through reforestation. For the case of coal miningin Colombia this metric has a value of 1.148(m2/t)/year.

Emission control efficiency by water spraying This metriccorresponds to the efficiency obtained by Eq. 4 for agiven water spraying program (intensity of the applica-tions and average time between spray applications) overunpaved roads and areas exposed to wind erosion. Forthe case of coal mining in Colombia, this metric has avalue of 99%.

5 Conclusions

A standardized methodology to carry on TSP and PM10emissions inventories for open-pit mining was presented. Itis based mainly on the USEPA emission factors. It wasimplemented in a spreadsheet and made available to thepublic domain through internet. Several tools wereimplemented within the spreadsheet to prevent typographicalerrors and to facilitate its use. It also has incorporatedthe feedback of coal mining companies, environmentalauthorities, and private consulting firms.

The emission inventories can also be used to identify thesub-activities within the mining operation that require addi-tional effort to control particle emissions.

This tool was used to obtain the TSP and PM10emission inventories of seven out of eight open-pit coalmining operating in the northern part of Colombia,which is considered as one of the largest open-pit coalmining areas of the world. Results showed that onaverage, these companies emit 0.726 kg of TSP and0.180 kg of PM10 per ton of coal produced; that onaverage, they use 1.148 m2 per ton of coal producedyearly; and that they control particle emission fromunpaved roads with a 99% of efficiency by water spray-ing. Companies reported that by spraying water between1 and 2 l/m2 between two and four times every hour,

Pit, 42%

Dump,18%

Stock,14%

Va-Pit-Dump, 15%

Va-Pit-Stock, 7%

Va-Perim,4%

Pit16%

Dump60%

Stock11%

Va-Pit-Dump11%

Va-Pit-Stock1%

Va-Perim1%

a

b

Fig. 5 a Average contribution to TSP emissions of each area sourcepresent in open-pit mining for the case of coal production in Colombiaduring 2009. b Average contribution to PM10 emissions of each areasource present in open-pit mining for the case of coal production inColombia during 2009


they have been able to reduce on average 72% of TSPemissions. However transportation of material over un-paved roads is still the main source of TSP followed bycoal handling and wind erosion.

Additional work is required to adapt the emission factorsimplemented in the proposed methodology to the localparticular conditions of each mine. Further work is also

required to determine the conditions of water spraying(intensity of the applications and average time between sprayapplications) that minimize water use and cost of the particleemission control programs for open-pit mines.

Acknowledgments This work was financed by the ColombianMinistry of the Environment.

Appendix A

Table 3 Activities involved in open-pit mining and its classification by area source

Operation Activity Equation ID Classification by area source

TSP PM10

Topsoil handling Top soil removal by scraper 1 0 Pit

Bulldozing 2 20 Pit

Loading 3 21 Pit

Transportation 4 22 Pit 25%, dump 25%, roads 50%

Unloading 5 21 Dump

Drilling and blasting (coal and overburden) Drilling 6 0 Pit

7 0 Pit

Blasting 8 23 Pit

Overburden handling (traditional way) Bulldozing in the loading area 9 24 Pit

Loading 3 21 Pit

Transportation by trucks 4 22 Pit 25%, dump 25%, roads 50%

Unloading 10 21 Dump

Bulldozing in the unloading area 9 24 Dump

Overburden handling by dragline and conveyor Overburden removal with dragline 11 25 Pit

Truck loading with dragline 11 25 Pit

Bulldozing in pits 9 24 Pit

Truck loading with bulldozer y/o feeder 3 21 Pit

Transportation by truck 4 22 Pit 25%, dump 25%, roads 50%

Truck unloading 10 21 Dump

Chute loading with scrapper 3 21 Pit

Overburden unloading from conveyor 10 21 Dump

Bulldozing in the unloading area 9 24 Dump

Coal handling Bulldozing 2 20 Pit

Truck loading 12 26 Pit

Transportation by truck 4 22 Pit 25%, dump 25%, roads 50%

Unloading 13 21 Patio

Stocking with bulldozer 2 20 Patio

Train loading 14 21 Patio

Transportation by train 15 0 Roads

Other operations Wind erosion in coal piles 16 27 Patio

Wind erosion in exposed areas 17 27 Dump

Road maintenance 18 28 Pit

Light duty traffic 19 29 Pit 25%, dump 25%, roads 50%


List of symbols

A Blasting horizontal area with a dept 5.33 m/s (percent)

Ei Estimate the mass of TSP or PM10 that isreleased into the atmosphere by activityi (kilograms per year)

Ef,l Emission factor for aggregate handlingand storage in piles of granulatedmaterial (kilograms of TSP/ton)

Ef,i Emission factor for activity i(kilogram per intensity of activity i)

Table 4 TSP and PM10 emis-sion factors used for each activ-ity involved in open-pit mining

Equation ID Equation Units Reference

1 0.029 kg TSP/t USEPA (2008)

2 35:6 s1:2

M1:4 kg TSP/h USEPA (2008)

3 0:0012U=2:2 1:3M=2 1:4 ; 0:018 kg TSP/t USEPA (2006b)

4 1:38 s12 0:7 W

3

0:451 s1 r kg TSP/VKT USEPA (2006a),Cowherd (1988)5 0:0012

U=2:2 1:3M=2 1:4 ; 0:02 kg TSP/t USEPA (2006b, 2008)

6 0.59 kg TSP/hole USEPA (2008)

7 0.1 kg TSP/hole USEPA (2008)

8 0.00022 A1.5 kg TSP/blast USEPA (2008)

9 2:6 s1:2

M1:3 kg TSP/h USEPA (2008)

10 0:0012U=2:2 1:3M=2 1:4 ; 0:001 kg TSP/t (US EPA 2006b, 2008)

11 0:0046 d1:1

M0:3kg TSP/m3 USEPA (2008)

12 0:58M1:2 kg TSP/t USEPA (2008)

13 0:0012U=2:2 1:3M=2 1:4 ; 0:033 kg TSP/t (USEPA 2008)

14 0:0012 U=2:2 1:3

M=2 1:4 ; 0:014 kg TSP/t USEPA (2008)15 1.8U* kg TSP/(Ha h) USEPA (2008)

16 1.8U kg TSP/(Ha h) USEPA (2008)

17 0.85 Ton TSP/(Ha-year) USEPA (2008)

18 0.0034S2.5 kg TSP/VKT USEPA (2008)

191:6914 s=12 s=30 0:3

M=0:5 0:3 0:0001325 kg TSP/VKT USEPA (2006a)20 0:75 8:44 s1:5M1:4 kg PM10/(h bulldozer) USEPA (2008)21 0:00056 U=2:2

1:3

M=2 1:4kg PM10/t USEPA (2006a, b)

220:423 s12

0:9 W3

0:451 s1 rkg PM10/VKT USEPA (2006a),

Cowherd (1988)

23 0.52 (0.00022) A1.5 kg PM10/blast USEPA (2008)

24 0:75 0:45 s1:5M1:4 kg PM10/h USEPA (2008)25 0:75 0:0029 d0:7M0:3 kg PM10/m3 USEPA (2008)26 0:75 0:0596M0:9 kg PM10/t USEPA (2008), Missouri

Department of NaturalResources (2009)

27 0:000095 s1:5 bc235

e15 kg PM10/(m

2 year) Missouri Departmentof Natural Resources(2009)

28 0.60 (0.0056) S20 kg PM10/VKT USEPA (2008), MissouriDepartment of NaturalResources (2009)

29 0:507s=12 s=30 0:2M=0:5 0:5 1 s1 r kg PM10/VKT USEPA (2006a),

Cowherd (1988)


k Intensity of the applications (liters persquare meter)

m Number of days in the period (days)M: Moisture content of the handled material

(percent)Mp Material's propertiesMc Meteorological conditionsp Average daytime evaporation rate

(millimeter per hour)n Number of rainy days in the period with

precipitation levels exceeding 0.254 mm (days)r Average daily traffic (vehicles per hour)R2 Coefficient of determinationSa Emitting activityS Average vehicle speed (kilometers per hour)s Silt content (mesh 200) of the handled material

or on the surface of the road (percent)t Average time between spray applications (hour)U Wind speed (meters per second)U* Average train speed (meters per second)VKT Kilometers traveled per vehicle (kilometers

per vehicle)W: Truck average weight (tons)i, j Indexes, , , Experimental constants.j Efficiency of the emission control measure

j (percent)s Efficiency of emission controls for spraying

water (percent)* Constant values area applied whenever

equations are not applicable

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c.11356_2012_Article_778.pdfStandardized emissions inventory methodology for open-pit mining areasAbstractAbstractAbstractAbstractIntroductionStandardized emission inventory methodologySpecial considerationsImplementation of the methodology on a spreadsheet

ResultsComparison of the operational parameters reported by coal mining companiesComparison by total emissionsComparison of emissions by mining activitiesComparison of emissions by area source

RecommendationsConclusionsAppendix AReferences

Standardized Emissions Inventory Methodology mining 234

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