O iginal a icle
En i onmen al and mine closu e cos s in he block sequencing o a
coal deposi
Da id Oli e os-Sepúl eda
a,*
, Ma c Bascomp a-Massan´
es
a,1
, Gio anni F anco-Sepúl eda
b,1
a
Uni e si a poli `
ecnica de Ca alunya, Escola Poli `
ecnica Supe io d’Enginye ia de Man esa. Man esa, Edi ici MN1. A . de les Bases de Man esa, 61-73 08242 Man esa,
Spain
b
Uni e sidad Nacional de Colombia, Facul ad de Minas. A . 80 #65 - 223, Villa Flo a, Medellín, Robledo, Medellín, An ioquia, Colombia
ARTICLE INFO
Keywo ds:
S a egic mine planning
En i onmen al cos s
Closu e cos s
Social cos s
ABSTRACT
A p esen , ex ac i e indus ies ace signi ican sus ainabili y challenges in he e i o ies whe e hey ope a e.
T adi ionally, en i onmen al and social a iables ha e no been in eg a ed in o he p ocesses o op imiza ion and
sequencing in mining plans, leading o ou comes ha a e no holis ic and a e accompanied by highe isks.
E o s o educe geological, economic, and ope a ional unce ain y ha e seen conside able p og ess in ecen
yea s. Howe e , limi ed esea ch add esses he en i onmen al and social unce ain ies ha mining p ojec s may
ace. This esea ch p oposes he in e naliza ion o he cos s associa ed wi h he closu e o he mine, en i on-
men al cos s and cos s o con lic esolu ion, calcula ed based on equa ions sugges ed by a ious au ho s in he
s a e o he a . The base case o an open pi coal mine loca ed in Colombia wi h p e iously es ablished ini ial
condi ions and associa ed cos s, calcula ed a e he op imiza ion p ocess, is add essed. Subsequen ly, a new case
is gene a ed in which hese cos s a e cha ged o he economic alua ion o he mine al, punishing i s calo i ic
alue. A he end, a sensi i i y analysis is ca ied ou wi h he u u e p ojec ions o he p ice o coal. The esul s
ob ained indica e ha , by in e nalizing hese cos s, i is possible o educe he in es men isk and he e is an
imp o emen in he ope a ional, social and en i onmen al pe o mance o he case s udy. Resul s ha could
bene i he company, he S a e and he communi ies.
1. In oduc ion
In ecen decades, he in eg a ion o en i onmen al a iables in o
mine planning has gained inc easing signi icance, d i en by he g owing
egula o y demands and he need o adop mo e sus ainable mining
p ac ices. In ce ain egions, pa icula ly in de eloping coun ies, min-
ing ope a ions ha e le a subs an ial en i onmen al legacy, a ec ing
local ecosys ems and communi ies. As a esul , e alua ing and e ec-
i ely managing hese impac s has become a c i ical challenge o he
indus y, especially wi h he ad en o sus ainable de elopmen con-
cep s and he Sus ainable De elopmen Goals (SDGs) (UN, 2015).
T adi ionally, esou ce ex ac ion op imiza ion ocused on economic
and ope a ional pa ame e s. Howe e , he e has been a g owing
ecogni ion ha en i onmen al and social ac o s mus also be consid-
e ed, as ailu e o do so may esul in addi ional cos s o bo h companies
and go e nmen s (Lechne e al., 2016; McCullough e al., 2018).
Se e al s udies sugges ha mine planning should be app oached
holis ically, aiming no only o maximize economic bene i s bu also o
minimize nega i e en i onmen al impac s (Heyda i and Osanloo, 2024;
Liu e al., 2024). The cos s associa ed wi h ehabili a ing a ec ed a eas
and mi iga ing un o eseen en i onmen al consequences a e o en
signi ican ly highe when add essed a he end o he mine’s li e cycle,
a he han being p og essi ely in eg a ed in o he ea ly planning s ages
(Ge y and Mo ison-Saunde s, 2020). Conduc ing ex-an e assessmen s
o en i onmen al impac s and inco po a ing hem in o block sequencing
models and inal pi designs a e c ucial o ensu ing long- e m sus ain-
abili y (Kosinskiy e al., 2019; X. Xu e al., 2017).
In his con ex , he legisla ion in coun ies such as Chile, he Uni ed
S a es, and Aus alia manda es ha mining companies accoun o hese
cos s in hei e alua ions, employing clea me hodologies o
* Co espondence au ho a . Uni e si a poli `
ecnica de Ca alunya, Escola Poli `
ecnica Supe io d’Enginye ia de Man esa. Man esa, Edi ici MN1. A . de les Bases de
Man esa, 61-73 08242 Man esa, Spain.
E-mail add esses: [email p o ec ed] (D. Oli e os-Sepúl eda), [email p o ec ed] (M. Bascomp a-Massan´
es), [email p o ec ed] (G. F anco-
Sepúl eda).
1
P incipal au ho
Con en s lis s a ailable a ScienceDi ec
The Ex ac i e Indus ies and Socie y
jou nal homepage: www.else ie .com/loca e/exis
h ps://doi.o g/10.1016/j.exis.2025.101668
Recei ed 5 Feb ua y 2025; Recei ed in e ised o m 3 Ap il 2025; Accep ed 5 Ap il 2025
The Ex ac i e Indus ies and Socie y 23 (2025) 101668
A ailable online 18 Ap il 2025
2214-790X/© 2025 The Au ho (s). Published by Else ie L d. This is an open access a icle unde he CC BY-NC license ( h p://c ea i ecommons.o g/licenses/by-
nc/4.0/ ).
quan i ica ion. This ep esen s a signi ican s ep owa d embedding
sus ainabili y in o mining p ojec s. Howe e , despi e egula o y p og-
ess, no able gaps emain in he me hodology o accu a ely quan i ying
en i onmen al and closu e cos s (Oblasse and Chapa o, 2008; Pie -
zyk-Sokulska e al., 2015). As a esul , ecen s udies p opose a ious
alua ion me hodologies ha encompass no only di ec ehabili a ion
cos s bu also hose a ising om he loss o ecosys em se ices and
ca bon emissions (Rahmanpou and Osanloo, 2017; X. C. Xu e al.,
2014).
A key app oach o add essing hese challenges is he applica ion o
op imiza ion echniques ha in eg a e en i onmen al a iables in o he
mine planning p ocess. Va ious algo i hms and simula ion models, such
as hose based on Mon e Ca lo simula ions and decision ee analysis,
ha e been p oposed o es ima e he en i onmen al cos s linked o
mining ex ac ion and ehabili a ion (Pa icheh and Osanloo, 2017).
These app oaches enable no only he quan i ica ion o bo h di ec and
indi ec impac s bu also he e alua ion o al e na i e scena ios o
iden i y he mos e ec i e exploi a ion and closu e s a egies (Rahimi
and Ghasemzadeh, 2015).
Mo eo e , ecen s udies unde sco e he impo ance o inco po a ing
echniques like he P e e ence Ranking O ganiza ion Me hod o
En ichmen E alua ion (TOPSIS) and g ey clus e ing, among o he s, in
mul ic i e ia decision analysis o mine planning (Adibi e al., 2015).
These me hods acili a e he in eg a ion o echnical, economic, social,
and en i onmen al ac o s, empowe ing mo e in o med and esponsible
decision-making (Mo adi and Osanloo, 2015; Tabesh e al., 2023). While
signi ican esea ch exis s on in eg a ing en i onmen al a iables in o
mine planning, ew s udies di ec ly inco po a e en i onmen al and
closu e cos s in o block models comp ehensi ely.
In e ms o closu e cos s, ecen esea ch by Xu e al. (X. Xu e al.,
2017) and Neh ing and Cheng (Neh ing and Cheng, 2016) has demon-
s a ed ha ex ending a p ojec ’s li espan by inco po a ing closu e cos s
ea ly in he planning p ocess can yield economic bene i s beyond ini ial
p ojec ions. The ea ly inclusion o hese cos s and he scheduling o
p og essi e closu es h oughou he p ojec li e cycle a e mo e
cos -e ec i e han add essing hem eac i ely a he end o he exploi-
a ion phase (X. Chuan Xu e al., 2018). P og essi e closu e me hodol-
ogies, suppo ed by Geog aphic In o ma ion Sys ems (GIS) and o he
analy ical ools, ha e p o en e ec i e in moni o ing en i onmen al
impac s and adjus ing mining ope a ions o p e en o mi iga e u he
damage (Liao e al., 2013).
Fu he mo e, he economic alua ion o ecosys em se ices, bo h
di ec and indi ec , is inc easingly ecognized as an in eg al componen
o mining p ojec e alua ion (X. Xu e al., 2017). These cos s, which
encompass biodi e si y loss, diminished ai and wa e quali y, and
nega i e e ec s on soils and landscapes, mus be inco po a ed in o
op imiza ion models o mo e accu a ely e lec he ue cos s o mining
ope a ions (Gu e al., 2013). In his ega d, esea ch by Kosinskiy e al.
(2019) and Rahmanpou and Osanloo (2017) emphasizes he impo -
ance o quan i ying he ecological oo p in and he damage in lic ed on
ecosys em unc ions by ex ac i e ac i i ies, which is c i ical o
adop ing a sus ainable mining app oach.
To educe isks and p o ide al e na i e economic e alua ions o
bo h companies and go e nmen s, his s udy ocuses on he inclusion o
en i onmen al, social, and mine closu e cos s o an open-pi coal de-
posi in no he n Colombia, quan i ied using me hodologies iden i ied in
he li e a u e. Building on p e ious esea ch, an app oach will be
de eloped o op imize mine planning by in eg a ing hese cos s ea ly in
he ope a ion, inco po a ing hem in o block sequencing and inal pi
selec ion, o achie e e icien and sus ainable ex ac ion.
2. Ma e ials and me hods
A e iden i ying he s a e o he a and he concep ual amewo k
p esen in he li e a u e, he key aspec s o he case s udy we e
add essed, including i s echnical, en i onmen al, and social
cha ac e is ics, alongside he co esponding economic alua ion. Gi en
he mo phology o he mine al deposi and he ope a ional condi ions o
he p ojec , i was de e mined ha he p e iously calcula ed cos s
should be in eg a ed in o he geological model. This app oach is in en-
ded o be applied speci ically o each deposi , as he unique cha ac e -
is ics o each case s udy in he li e a u e p eclude he di ec applica ion
o esul s o o he p ojec s.
To quan i y he cos s associa ed wi h bo h di ec and indi ec
ecosys em se ices (en i onmen al cos s), he me hodology p oposed by
Xiao-Chuan e al. (X. C. Xu e al., 2014) was selec ed, as i p o ides clea
and concise guidelines o ob aining a comp ehensi e economic e alu-
a ion in mining p ojec s. Fo calcula ing he cos s ela ed o mine closu e
ac i i ies, e e ence was made o Law 20,551 o SERNAGEOMIN (Na-
ional Se ice o Geology and Mining) (Se nageomin, 2014). Howe e ,
due o di e ences in na u al condi ions compa ed o he case s udy,
some modi ica ions and co ec ion ac o s we e applied. Fo a mo e
de ailed unde s anding o he equa ions and me hodologies employed,
eade s a e encou aged o consul he o iginal sou ces di ec ly.
The cos s associa ed wi h con lic esolu ion we e es ima ed based on
calcula ions e e ing o he numbe o people di ec ly a ec ed, he
a e age numbe o indi iduals pe household, and a hypo he ical eco-
nomic compensa ion amoun ha indi iduals would be willing o accep
annually o he impac s gene a ed by he mine.
Based on he geological model, and u ilizing Deswik mine planning
so wa e, wo mining schedules and block sequencing scena ios we e
de eloped. The i s co esponds o "Case A," whe e adi ional planning
is applied, and he second, "Case B," in ol es in eg a ing en i onmen al,
closu e, and social cos s wi hin he block model. I is impo an o no e
ha Deswik employs algo i hms o sol e scheduling and sequencing
p oblems, conside ing empo al a iables, ope a ional cons ain s, and
mul iple des ina ions o ex ac ed ma e ial. Addi ionally, he so wa e
inco po a es algo i hms o calcula ing he inal en elope o he
exploi a ion (Deswik, 2018; Poniewie ski, 2018).
Finally, using his o ical he mal coal p ices, u u e p ice p ojec ions
we e de i ed. This will acili a e a sensi i i y analysis, whe e h ee p ice
scena ios co esponding o he 25 h pe cen ile (P25), 50 h pe cen ile
(P50), and 75 h pe cen ile (P75) a e p oposed. These p ojec ions a e
gene a ed using @Risk 8.2, based on he dis ibu ion unc ion de i ed
om he comple e da ase . Fig. 1 summa izes and isually illus a es he
p oposed me hodology o he de elopmen o his a icle.
2.1. Case s udy
The case s udy in ol es a sedimen a y coal deposi whe e an open-
pi mine is being de eloped in no he n Colombia. A he eques o
he company and unde a con iden iali y ag eemen , he name o he
company and he exac loca ion o he p ojec will no be disclosed;
howe e , he p o ided da a is pa o an ac ual ope a ion. The deposi is
desc ibed as a syncline composed o 26 coal seams, which exhibi a -
iable hicknesses along hei ex en , wi h pinch-ou s in some a eas. Like
he hicknesses, he physicochemical cha ac e is ics a e no con inuous,
which is why i is necessa y o de elop a block model wi h pa ial
quali ies, conside ing he a e age p ope ies o he seams ha a e
included in each block wi hin he model. The dimensions used o c ea e
he block model a e 10 m x 10 m x 10 m, which we e g ouped in o
mac o-blocks o 50 m x 50 m x 50 m o educe compu a ional
complexi y.
In Fig. 2, he mo phology and opog aphy o he sedimen a y deposi
can be obse ed. The deposi is p ojec ed o ex end 4.5 km in leng h and
2 km in wid h a he su ace.
The g ay s a a ep esen he ma e ial o in e es (coal), while he
o ange s a a indica e was e ma e ial ha will need o be disposed o in
dumps, should i be ex ac ed in o de o each he coal seams. Table 1
p esen s he main condi ions and geological cha ac e is ics o he de-
posi in he case s udy.
The ini ial cos s ha will be conside ed o bo h scena ios include
D. Oli e os-Sepúl eda e al.
The Ex ac i e Indus ies and Socie y 23 (2025) 101668
2
anspo a ion cos s and p ocessing cos s. Due o he a ia ion in mining
cos s (which include anspo a ion and blas ing) based on block dep h,
an equa ion was de eloped as a unc ion o Z, whe e he maximum alue
is 29.2 USD/ o he deepes blocks (Z = − 120) and he minimum alue
is 11.7 USD/ o he shallowes blocks (Z =230). The p ocessing cos s
conside ed a e ela ed o coal washing o educe he amoun o ash; one
o he assump ions made is ha all he mine al will unde go a washing
p ocess. In addi ion o hese cos s, inpu s such as was e and mine al
mining capaci ies, he discoun a e, mine al p ice, and inal pi wall
angle we e also aken in o accoun . Table 2 p esen s he conside a ions
made o he case s udy.
2.2. Cos quan i ica ion
The pa ame e s sugges ed by Xu e al. (2014), o es ima ing en i-
onmen al and ecological cos s a e summa ized in Fig. 3, whe e he
a iables conside ed o each componen can be obse ed: alue los
om di ec ecosys em se ices (Cd), alue los om indi ec ecosys em
se ices (Ci), and CO
2
emission cos s (Cp ). In his a icle, he oppo u-
ni y cos o de eloping ag icul u al ac i i ies will also be conside ed, as
ag icul u e is one o he p oduc i e oca ions in he s udy egion.
The closu e plan cos is calcula ed based on e e ence a es (Uni s o
Accoun , UF, in his case) and also akes in o accoun da a con ibu ions
om closu e plan alues in he mining indus y. Since each closu e case
has i s own speci ic cha ac e is ics, alue co ec ions a e made based on
geog aphic loca ion, al i ude abo e sea le el, and he dis ance o supply
cen e s. The Uni o Accoun (UF) is a Chilean accoun ing uni c ea ed o
adjus comme cial and accoun ing ansac ions ha change acco ding o
in la ion. The alue o he UF was assumed o be 37.44 USD.
This me hodology includes he cos s men ioned in Law 20,551 and
by Valdebeni o (Valdebeni o, 2015), which ela e he economic alues
o he cubic measu emen s o he e e ence a e (UF) o each wo k o
ins alla ion in he p ojec . These da a a e p esen ed in Table 3.
The co ec ion ac o s o his me hodology a e p oposed by Valde-
beni o o he Chilean case; howe e , since he case s udy is in Colombia,
i is sugges ed ha :
a) The geog aphical co ec ion ac o in he Chilean case a ies be-
ween 0.91 and 1.0 depending on he egion. *I is ecommended
ha his alue be modi ied based on he p ecipi a ion anges sug-
ges ed by he IDEAM (IDEAM, 2024), whe e a eas wi h lowe p e-
cipi a ion le els ange om 0 mm o 500 mm annually, and a eas
wi h highe p ecipi a ion le els exceed 11,000 mm annually. Table 4
speci ies he co ec ion ac o o be used o Colombia:
b) The al i ude co ec ion ac o is 1.0 o ope a ions below 3000 m
abo e sea le el (m.a.s.l.), 1.25 o ope a ions be ween 3000 and
Fig. 1. Summa y o he me hodology p oposed o he a icle.
Fig. 2. Mo phology and opog aphy o he deposi .
Table 1
Geological condi ions and cha ac e is ics o he deposi .
Pa ame e Value Uni
A e age ash 4,05 %
A e age coal densi y 1,31 /m
3
A e age calo i ic alue 12,812 BTU/lb
A e age sulphides 0,75 %
Numbe o mac oblocks 25,060 –
Annual ex ac ion capaci y 15 M
Table 2
Ini ial condi ions (inpu s) o he sequencing o Case A.
Pa ame e Value Uni
Coal p ice 46 USD/
Mining cos -(0.05*Z) +23.2 UDS/
Wash cos 3.8 USD/
Annual was e emo al capaci y 115 M
Discoun a e 8 %
A e age slope angle 50◦–
D. Oli e os-Sepúl eda e al.
The Ex ac i e Indus ies and Socie y 23 (2025) 101668
3
4000 m.a.s.l., and 1.45 o ope a ions abo e 4000 m.a.s.l. *Fo he
p esen a icle, hese alues a e modi ied based on he needs o he
coun y. The al i ude co ec ion ac o will be as ollows: p ojec s
below 1000 m.a.s.l. will ha e a co ec ion ac o o 1.0, ope a ions
be ween 1000 m.a.s.l. and 2000 m.a.s.l. will ha e a co ec ion ac o
o 1.25, and ope a ions be ween 2000 m.a.s.l. and 3000 m.a.s.l. will
ha e a co ec ion ac o o 1.45. In he coun y, ex ac i e ac i i ies
a e no allowed in a eas wi h al i udes g ea e han 3000 m.a.s.l.
(classi ied as pa amo zones).
c) I is ecommended o use he co ec ion ac o o supply cen e s (Fp)
based on he dis ance om he mining ope a ion o he nea es u ban
pe ime e o he supply cen e (x) using Eq. (1):
Fp=e0,0014 xi 0<x<650km (1)
Fp=2,5i 650km ≤x
Finally, he o al closu e cos s can be calcula ed by co ec ing he
di ec cos s ound in he cubic measu emen s using he co ec ion ac o s
men ioned ea lie , and adding he indi ec cos s and VAT, which in he
case o Colombia is 19 %.
To de ine he amoun o money ha should be in es ed as a esul o
con lic s wi h local communi ies, hypo he ical alues we e assumed
based on wha he inhabi an s would be willing o ecei e annually o
hei household as compensa ion o he mining p ojec ope a ion. Since
se e al mining p ojec s coexis in he s udy a ea, i was assumed ha he
numbe o a ec ed inhabi an s is p opo ional o he amoun o mine al
ex ac ed by he p ojec .
All he cos s calcula ed o his objec i e will be summed and uni ied
in o a single alue, which will hen be in e nalized in he mine planning
p ocess (calcula ion o he en elope, block sequencing, and scheduling).
2.3. In e naliza ion o cos s in he block model
A e de e mining Case A, he economic and ope a ional alues such
as NPV, LOM, ex ac ion a es, olumes, and he was e- o-mine al a io
(W/O) a e calcula ed. To in e nalize he cos s ob ained h ough he
p e iously men ioned me hodologies, hei equi alen alue in e ms o
BTU/cal pe me ic on was calcula ed. This allowed o he in eg a ion
wi hin he geological model, adjus ing he calo i ic alue o each o he
blocks. A new scena io (Case B) was calcula ed whe e he mine al blocks
a e al eady associa ed wi h en i onmen al, social, and mine closu e
cos s in e ms o hei calo i ic alue. The op imiza ion and sequencing
o his case will ha e di e en indica o s ha a e compa ed wi h Case A.
I is impo an o men ion ha , unlike o he ypes o mine als, coal
has se e al physicochemical p ope ies such as sul u , ash, and ola ile
pe cen ages, among o he s, ha i mus mee o expo pu poses. To
educe he compu a ional complexi y o he p oblem, he s udy con-
side s calo i ic alue as he only cha ac e is ic pa ame e o op imize he
mining plans, as he na u e o he mal mine al coal makes his i s main
p ope y.
The assumed p ice o he me ic on o he mal coal is 11,370 BTU/lb
o deli e ies made in e ms o ARA (Ams e dam, Ro e dam, An we p).
The e o e, he he mal coal quo a ion p ice (P on)mus be adjus ed by a
co ec ion ac o ela ed o i s calo i ic alue (Kc), which is based on a
mul iplying ac o in e ms o BTU/lb equi alen s o he p ice o he
me ic on (PBC). This is explained in Eq. (2):
P on =PBC ∗Kc
11,370 BTU/lb (2)
The inal pi calcula ion was pe o med using he pseudo low ool in
he Deswik mine planning so wa e. Subsequen ly, wi h ope a ional
cons ain s and he cha ac e is ics o he ope a ion, he sequencing and
scheduling o he ma e ial o be ex ac ed, which will be ca ego ized as
was e o mine al o in e es , will be ca ied ou . The objec i e o
es ablishing he iming and des ina ions o he ma e ials o be mined is
o make he mine plan ope a ional and iden i y a eas ha can be
abandoned om he ea ly s ages o he p ojec ’s li e in o de o begin
p og essi e closu e ac i i ies.
I is impo an o men ion ha he en i onmen al cos s o each block
may a y depending on i s speci ic chemical, physical, and spa ial
cha ac e is ics. Fo example, a senic con en can gene a e oxic
d ainage, py i e o sul ide con en can lead o acid d ainage, and su ace
ea u es such as di e en plan species o bodies o wa e can also in-
luence cos s. Howe e , accu a ely edis ibu ing he calcula ed cos s
non-uni o mly among he blocks and de e mining he po ion o hese
cos s ha should be alloca ed o mi iga ing a speci ic impac is chal-
lenging. Fo hese easons, and o educe compu a ional complexi y in
Fig. 3. En i onmen al cos s aken in o accoun in he a icle.
Table 3
Values o be in es ed o each o he mine’s wo ks and acili ies.
Pa ame e Uni Amoun o UF pe uni
S eel buildings and s uc u es on 15
Conc e e s uc u es m
2
12
Indus ial equipmen on 66
Camps and o ices m
2
1,1
Pi s, qua ies and subsidence a eas m
2
6
Was e dumps ha 186
Tailings deposi s ha 379
Leacha e ha 2628
Access oads m 0,3
Powe lines m 0,3
Rail lines m 8
Co e ages*ha 750–5000
Re ege a ion m
2
0,3
Soil emedia ion m
3
8
Haza dous indus ial was e on 8
*
They a e subjec o clima ic condi ions; o a eas wi h li le ain all such as
dese s, app oxima ely 750 UF/ha is ecommended, and o a eas wi h high
ain all, app oxima ely 5000 UF/ha.
D. Oli e os-Sepúl eda e al.
The Ex ac i e Indus ies and Socie y 23 (2025) 101668
4
he block model sequencing, a uni o m cos alloca ion was applied o
each block.
Fig. 4 g aphically explains he p oposed me hodology o he in e -
naliza ion o cos s in o he geological model, allowing o sequencing
wi h he included cos s.
2.4. Sensi i i y analysis
Two o he me hodologies ha will be used o in eg a e p ice un-
ce ain y a e ime se ies and p obabili y dis ibu ions, which employ
his o ical da a o gene a e po en ial u u e scena ios. The ecommended
selec ion index o conside in such models is he Akaike In o ma ion
C i e ion (AIC), which is an asymp o ic unbiased es ima o be ween he
p oposed model and he ue model (L´
opez, 2011). Using he "Time
Se ies" ool in he so wa e @Risk 8.2, i is possible o de i e hese ime
se ies h ough a ious simula ions o andom mo emen s ha ake in o
accoun he beha io o he mal coal p ices o any o he mine al. Based
on he esul s ob ained in Case B, an analysis will be pe o med in which
h ee hypo he ical u u e p ice scena ios a e p oposed, co esponding o
he 25 h pe cen ile (P 25), 50 h pe cen ile (P 50), and 75 h pe cen ile (P
75), using he p ice p ojec ion de i ed wi h @Risk 8.2. The coal p ices
used we e aken om he yea 1994 and a e exp essed in US dolla s pe
me ic on.
3. Resul s
3.1. Case A
3.1.1. Technical aspec s
A e comple ing he mining sequencing, esul s we e ob ained ha
desc ibe he economic, p oduc ion, and ope a ional cha ac e is ics o
Case A, which a e shown in Figs. 5, 6, 7, 8, and in de ail in Table A o he
Appendix. I is impo an o men ion ha , up o his poin , he Ne
P esen Value (NPV) o Case A has no been a ec ed by he mine closu e
cos s, en i onmen al cos s, and cos s ela ed o social con lic s, which
will be calcula ed in Sec ions 3.1.2, 3.1.3, and 3.1.4, espec i ely. In his
case, he cos s will be en e ed ex-pos , so ha once calcula ed, hey will
be sub ac ed om he NPV o his case o ob ain he eal NPV.
As can be seen in Figs. 5 and 6, he a e o mine al ex ac ion and
was e emo al emained cons an h oughou he li e o he mine (LOM),
which was 18 yea s. The only yea ha showed a subs an ial dec ease in
he ex ac ion a e was yea 3, which may be due o he mo phology o
he sedimen a y deposi , whe e a la ge amoun o was e mus be
emo ed o access he coal seams. Addi ionally, he was e- o-mine al
a io emained abo e 19, which caused a d op in he NPV o ha
pe iod o ime. Howe e , i is wo h no ing ha his a io also emained
ela i ely cons an , oscilla ing be ween 7.6 and 10.5 du ing he o he 17
pe iods. In Fig. 7, his beha io can be analyzed g aphically. The cu-
mula i e NPV is also shown in Fig. 8.
Based on he amoun o mine al and was e ex ac ed, he inal pi has
a dimension o 1023 hec a es, wi h a o al was e p oduc ion o 2.506
Table 4
Co ec ion ac o acco ding o ain all in he a ea o case s udy.
P ecipi a ion (mm pe yea ) 0–500 500- 1000 1000–1500 1500–2000 2000–2500 2500–3000 3000–4000 4000–5000 5000–7000 7000–9000 9000–11,000 >11,000
Co ec ion Fac o 0.91 0.92 0.93 0.94 0.95 0.96 0.98 1.00 1.02 1.06 1.11 1.15
Fig. 4. Me hodology o he inclusion o cos s.
D. Oli e os-Sepúl eda e al.
The Ex ac i e Indus ies and Socie y 23 (2025) 101668
5
million ons (M ), conside ing a swelling ac o o 1.2. O his o al
was e, 70 % is planned o disposal in was e dumps, while he emaining
30 % will be used o back illing in abandoned a eas. The e o e, o he
cons uc ion o he was e dumps, an a ea o 1200 hec a es is es ima ed,
wi h a heigh o <70 m
This con igu a ion ensu es ha he was e disposal and back illing
p ocesses align wi h he p ojec ’s en i onmen al and ope a ional plans,
helping manage he was e e ec i ely while also mi iga ing po en ial
impac s on he su ounding en i onmen .
3.1.2. Quan i ica ion o mine closu e cos s
Following he p oposed me hodology, he s ages o quan i ying he
closu e cos s we e ollowed. Table 5 de ines he cubic measu emen s o
each o he a iables ela ed o mine closu e cos s. Each o hese is
associa ed wi h an es ima ed in es men amoun in Uni s o Accoun ,
he cubic measu emen s, and he co esponding in es men amoun in
USD.
Co e ages(UF
ha)=0.4∗(A e age ain all(mm
yea ))+650 (3)
I is impo an o cla i y ha he e m "Co e " e e s o he wo ks ha
mus be ca ied ou o isola e ailings ponds, which a e gene ally ela ed
o he was e om me allu gical p ocesses. These a e no applicable o
he case s udy bu we e conside ed o he closu e o sedimen a ion
ponds ollowing he coal washing plan . I was assumed ha soil
emedia ion would ake place in a eas whe e he was e ock is disposed
o , and e ege a ion would occu in he a eas co esponding o he inal
pi .
Based on he alues de e mined o he calcula ion o closu e and
abandonmen cos s, a o al o 42,550,463 USD was ob ained, o which
he co ec ion ac o s mus be applied. In Table 6, he alues conside ed
o he applica ion o each co ec ion ac o a e desc ibed.
Finally, he ob ained alue, which co esponds o he o al amoun
ha should be in es ed o closu e and abandonmen ac i i ies, is
Fig. 5. Mine al ex ac ion by pe iod.
Fig. 6. Ex ac ion o was e ( ed) and mine al (blue) by pe iod.
Fig. 7. was e/mine al a io by pe iod.
Fig. 8. Ne P esen Value accumula ed h oughou he li e o he mine.
Table 5
Assumed alues o he a iables o calcula ing mine closu e cos s.
Pa ame e To al
uni s
Cos (USD)
S eel buildings and s uc u es 7.800 117.000
Conc e e s uc u es 60.000 720.000
Indus ial equipmen 20 1.320
Camps and o ices 3.500 3.850
Pi s, qua ies and subsidence a eas 1.023 6.138
Was e dumps 1.200 223.200
Tailings deposi s 5 1.895
Leacha e 0 0
Access oads 2.700 810
Powe lines 5.000 1.500
Railways 0 0
Co e ages (ha): They a e subjec o clima ic
condi ions, o a eas wi h li le ain all such as
dese s app oxima ely 750 UF/ha is ecommended,
a eas wi h high ain all a ound 5000 UF/ha.
5 5.750
Re ege a ion 10
′
230.000 3
′
069.000
Soil emedia ion 4
′
800.000 38
′
400.000
Haza dous indus ial was e 0 0
TOTAL 42′550.463
No e: To calcula e he amoun o UF o he ege a ion co e pa ame e , he
a e age alue o he lowe ange (250) and he uppe alue (11,000) om he
scale shown in Table 4 was used. Based on hese alues and he ecommenda-
ions in he Law, which sugges in es ing 750 UF/ha o a eas wi h low p e-
cipi a ion and 5000 UF/ha o o he a eas, Eq. (3) is p oposed o de e mine he
alue o he Co e pa ame e (ha).
D. Oli e os-Sepúl eda e al.
The Ex ac i e Indus ies and Socie y 23 (2025) 101668
6
56,905,665 USD.
3.1.3. Quan i ica ion o en i onmen al cos s
Acco ding o da a epo ed by he Ins i u e o Hyd ology, Me eo-
ology, and En i onmen al S udies – IDEAM (IDEAM, 2024), he con-
di ions unde which he mining p ojec in he case s udy is de eloped
co espond o a e es ial ecosys em in ended o ag icul u al ac i i ies,
speci ically a mosaic o pas u es and na u al spaces ypical o he
no he n egion o Colombia. The e a e no signi ican wa e cou ses in
he mining a ea, only seasonal s eams wi h low low du ing he ainy
seasons (Oc obe and No embe ), and annual p ecipi a ion a ies be-
ween 1000 and 1500 mm. In Table 7 he en i onmen al a iables and
he alues used o each o hem a e p esen ed, * was calcula ed based
on he ne annual income pe hec a e o maize c ops in Colombia, wi h
an a e age p ice o 256 USD/ . Simila ly, o calcula ing Cd, he op-
po uni y cos los by maize c ops in he inal pi a ea was conside ed,
wi h a yield o 38.1 ons o maize pe hec a e and h ee ha es s pe
yea .
I is impo an o men ion ha he a e age gasoline consump ion (eg)
was no conside ed, as all he equipmen used in he case s udy ope a es
on diesel uel, and he elec ici y used in he p ojec does no come om
he mal coal. The e o e, b, ac and ee a e assigned a alue o 0. The o al
en i onmen al cos s. As shown in Table 7, he o al en i onmen al cos s
ha he p ojec will incu amoun o 22,179,596 USD.
3.1.4. Quan i ica ion o cos s o esol ing social con lic s
The numbe o inhabi an s in he popula ions di ec ly a ec ed by he
mining ope a ions adjacen o he u ban cen e s o small illages in he
s udy a ea is 60,000, who a e di ec ly o indi ec ly in luenced by he
coal ex ac ion p ojec s aking place he e. To calcula e he numbe o
inhabi an s a ec ed by he p ojec in he case s udy, a p opo ional
ela ionship was es ablished be ween he amoun o mine al ex ac ed in
he las yea in he mining a ea and he amoun ex ac ed by he ope -
a ion unde analysis. Thus, he p ojec ed annual p oduc ion is
15,000,000 ons o coal, while he a e age p oduc ion o all he p ojec s
in he egion was 80,215,000 ons o coal, accoun ing o 18.7 % o he
o al p oduc ion in he mining a ea (11,220 people). Addi ionally, i was
assumed ha he a e age numbe o people pe amily uni is 6, and he
a e age amoun o money each amily is willing o ecei e is 827 USD/
yea . The e o e, a o al o 1870 amily uni s will ecei e he compen-
sa ion, equi alen o 1546,478 USD/yea and 27,836,602 USD o he
en i e li e o he mine. This la e alue will ep esen he o al social
cos s o he case s udy.
The o al calcula ed cos s amoun o 106,921,863 USD, which co -
esponds o he o al cos s ha had o be calcula ed o he case s udy. I
his alue is sub ac ed om he 1060,780,000 USD co esponding o
he ne p esen alue (NPV) o he sequencing o Case A, he esul is
953,858,137 USD, which ep esen s he eal NPV o his case. I is
necessa y o cla i y ha hese alues a e deduc ed di ec ly om he NPV
in yea 0 and a e no a ec ed by he discoun a e, as hey a e gene ally
paid be o e he s a o he p ojec as a inancial gua an ee, depending
on he legal amewo k in which he mine ope a es.
3.2. In e naliza ion o cos s in mining op imiza ion (Case B)
Once Case A has been iden i ied wi h i s economic and ope a ional
cha ac e is ics, such as NPV, LOM, ex ac ion a es, olumes, and he
was e- o-mine al a io al eady de e mined, i is possible o in e nalize
he calcula ed cos s o he mining sequencing by calcula ing hei
equi alen alue in BTU/cal o me ic ons.
Acco ding o he me hodology p oposed, he cos s o be in e nalized
in he mining blocks will include he o al cos s o closu e and aban-
donmen , en i onmen al cos s, and con lic esolu ion cos s, which
amoun o 106,921,863 USD. I is he e o e necessa y o calcula e hei
equi alen in BTU/lb o accoun o he quali y o he coal o be
ex ac ed. The alue used is he one men ioned in Eq. (3), whe e he
assumed cos o 46 USD/ on has a calo i ic alue o 11,370 BTU/lb,
esul ing in a o al o 1215,701,582,310 BTU/lb o be in e nalized and
inco po a ed in o he model.
The calcula ed BTU/lb will be dis ibu ed o he blocks ex ac ed in
Case A by dec easing he coal quali y. This will allow he sequencing
algo i hm o he so wa e o educe he economic alue o each block
and make new decisions ega ding i s des ina ion (plan o was e dump)
and he pe iod in which i will be ex ac ed.
I is impo an o men ion ha educing he coal quali y will change
he economic and echnical condi ions o he p ojec , such as he amoun
o was e and mine al o be ex ac ed, he was e- o-mine al a io, he
NPV, and he LOM. Howe e , hese esul s would al eady include he
Table 6
Final calcula ion o closu e and abandonmen cos s aking in o accoun
co ec ion ac o s. *The assumed alue o he co ec ion ac o a, co esponding
o he co ec ion ac o o he u ban cen e , is 5 km.
Ini ial calcula ion 42′550.463 USD
Co ec ion Fac o Value Value
a 0,93 39
′
571.930 USD
b 1 39
′
571.930 USD
c 1007 39
′
849.905 USD
O he s Indi ec cos s 0,20 47
′
819.887 USD
VAT 0,19 56
′
905.665 USD
Table 7
Assumed alues o calcula ing en i onmen al cos s.
Symbol Meaning Uni Value
VsSoil e osion con ol $ 71,71
sSoil e en ion capaci y /hm
2
/a 42,50
* Annual ne soil income om local
c ops
$/hm
2
9.753,10
ρ
sSoil densi y o cul i a ion /m
3
1,30
hmSoil hickness m 0,40
VaAi pollu an up ake $ 1694,82
qNe p ima y p oduc i i y on/(Ha*y ) 38,10
cCa bon mass con e sion ac o C o
CO
2
dimensionless 3,67
cCCa bon cap u e and s o age cos $/ 65
ysSO
2
abso p ion capaci y o
ege a ion
/hm
2
/a 0,15
csSO
2
emo al and con ol $/ 114
ydDus abso p ion capaci y o o es /hm
2
/a 21,65
cdDus emo al and con ol cos $/hm
2
27
VoOxygen elease $ 182,88
coOxygen ex ac ion cos $/ 4
V Runo con ol $ 9900
pA e age annual ain all (mm/a) 1250
kP opo ion o ain all causing uno dimensionless 0,30
Vege a ion-caused uno low
educ ion coe icien
dimensionless 0,24
c Cos o s o ing wa e in a ese oi $/m
3
11.000
VnSoil nu ien o ma ion $ 67,38
kNSoil ni ogen con en . dimensionless 0,0043
PNNi ogen e ilize cos $/ 211
pP o P
2
O
5
mass con e sion ac o dimensionless 2,2903
kpSoil phospho us con en dimensionless 0,00,037
PpPhospho us e ilize cos $/ 113,82
kKSoil po assium con en dimensionless 0,00,242
PKPo assium e ilize cos $/ 316
CiIndi ec eco-se ices los alue (Sum
o he abo e V)
$ 11.924,79
CdDi ec eco-se ices los alue
(Oppo uni y cos s)
$ 9.753,1
edA e age diesel consump ion pe
onne o ma e ial emo ed
kg/ 0,67
dCa bon emission ac o o diesel dimensionless 0,87
cCCa bon cap u e and s o age cos $/ 75
Cp CO
2
emission cos s o ene gy
consump ion
$ 0.4
TOTAL ($/ha) 21.680,93
TOTAL ($) 22
′
179.595,78
D. Oli e os-Sepúl eda e al.
The Ex ac i e Indus ies and Socie y 23 (2025) 101668
7
cos s calcula ed in he p e ious sec ion, hus signi ican ly educing he
isks associa ed wi h inco po a ing hem ex-pos .
Figs. 9, 10, 11, 12, and he de ailed Table B in he Appendix show he
esul s ob ained a e in e nalizing he cos s and pe o ming he block
sequencing o Case B.
4. Discussion
The esul s ob ained in he cos in e naliza ion case show conside -
able a ia ions in he was e- o-mine al a io, he amoun o was e
ex ac ed, NPV, and LOM. I is impo an o no e ha in bo h cases, he
numbe o mine al ex ac ed was simila —253.47 M o Case A and
251.74 M o Case B. This is signi ican as i con i ms he amoun o
ese es p esen in he deposi and indica es ha he inclusion o cos s
did no d as ically a ec his alue in ou case s udy.
Al hough simila ex ac ion le els we e ob ained, he ex ac ion a e
expe ienced no able changes, which a e impo an o analyze. Fi s , i
can be obse ed ha he sequencing p ocess p o ided he so wa e wi h
mo e lexibili y in he ex ac ion a e, sugges ing o he use ha
ex ac ion pe iods should exceed 15 M o yea s 9 and 10. I his
" lexibili y" we e no implemen ed du ing hese wo pe iods, he NPV
would likely be se e ely impac ed. This could be explained by he
mo phology o he deposi , as i is necessa y o ex ac a bi mo e in hese
yea s o each he nex coal seams. O he wise, ex ac ing hem in sub-
sequen pe iods may no be economically iable, also a ec ing u u e
p oduc ion. I is impo an o emphasize ha his inc ease in he
ex ac ion a e ep esen s only 3 % o he 15 M ini ially conside ed.
Secondly, annual p oduc ion in Case B showed ewe a ia ions han in
Case A, which had educed ex ac ion o yea s 3 and 9, wi h alues o
6.01 M and 10.94 M , espec i ely. Case B only p esen ed signi ican
a ia ions in yea 16, wi h an ex ac ion o 13.44 M o coal.
Ano he ac o ha can be analyzed is he amoun o was e ex ac ed.
This is c ucial as i can ep esen changes in he p ojec ’s en i onmen al
pe o mance. As no ed in ea lie sec ions, i mo e was e needs o be
emo ed, he associa ed ehabili a ion and closu e cos s will also in-
c ease. In bo h cases, he ex ac ion a e is cons an and luc ua es
wi hin he same alues. Howe e , in Case A, 2088.61 M o was e was
ex ac ed, while in Case B, 1970.73 M was ex ac ed. This could be
explained by he educ ion in LOM, which was sho ened by one yea ,
meaning he e would be no need o emo e he mine al om yea 18, as
con inuing ex ac ion would no be economically iable. The educ ion
in LOM and he amoun o ex ac ed mine al indica es ha ex ac ing
mo e mine al, e en i i is in si u, is no always he mos cos -e ec i e
s a egy. In ac , ex ac ing g ea e quan i ies o mine al could be
coun e p oduc i e o he p ojec ’s NPV, as i will end o dec ease.
Ano he ac o indica ing be e en i onmen al pe o mance is he
was e- o-mine al a io, as i shows ha less was e is equi ed o ob ain
he same amoun o coal. This was one o he indica o s ha imp o ed in
compa ison o Case A, as he a e age alue dec eased om 8.24 o 7.84
(app oxima ely 5 %) and also showed mo e s able beha io (wi h no
alue exceeding 8.56), unlike in Case A, whe e pe iods wi h a was e- o-
mine al a io o 19.5 and 10.51 we e obse ed.
Las ly, and as expec ed, he NPV o Case B showed a educ ion
compa ed o Case A. Despi e he NPV o 898.30 million USD being 4 %
lowe han he ini ially calcula ed alue, his scena io p esen s lowe
en i onmen al and social isks and unce ain ies han he ini ial case.
The e o e, he po en ial en i onmen al issues and communi y con lic s
would al eady be in eg a ed in o he mining plans. This is o u mos
impo ance as i gua an ees ha he chances o suspending o p ema-
u ely closing he p ojec a e educed. I is impo an o emembe ha
his is one o he main challenges aced by mining p ojec s a ound he
wo ld, especially in La in Ame ica, whe e a ious social mo emen s
ha e in luenced he suspension o closu e o p ojec s ha we e ei he
al eady ope a ing o abou o s a .
Fig. 9. Mine al ex ac ion by pe iod in Case B.
Fig. 10. Ex ac ion o was e and mine al by pe iod in Case B.
Fig. 11. Was e/Mine al a io by pe iod in Case B.
Fig. 12. Accumula ed Ne P esen Value, wi h in e nalized cos s, h oughou
he li e o he mine.
D. Oli e os-Sepúl eda e al.
The Ex ac i e Indus ies and Socie y 23 (2025) 101668
8
4.1. Sensi i i y analysis
Due o he unce ain y associa ed wi h he a iables in ol ed in he
esul s o op imiza ion p ocesses in mining plans, he u u e a ia ion o
some o hese a iables, especially he p ices o he mine als o be
ex ac ed, mus be conside ed. Two o he me hodologies used o in e-
g a e p ice unce ain y a e ime se ies and p obabili y dis ibu ions,
which employ his o ical da a o gene a e possible u u e scena ios
(F anco Sepúl eda e al., 2012). The ecommended selec ion c i e ion
o his ype o model is gene ally he Akaike In o ma ion C i e ion
(AIC), which is an asymp o ic unbiased es ima o be ween he p oposed
model and he ue model (L´
opez, 2011). Using he "Time Se ies" ool o
@Risk 8.2 so wa e (PALISADE, 2023), i is possible o gene a e hese
ime se ies h ough di e en simula ions o andom mo emen s ha
accoun o he beha io o he coppe p ice in his case.
Conside ing he esul s ob ained in Case B, h ee hypo he ical u u e
p ice scena ios a e p oposed co esponding o he 25 h (P25), 50 h
(P50), and 75 h (P75) pe cen iles, ob ained h ough a p ice p ojec ion
wi h @Risk 8.2. The coal p ices used we e aken om a ime pe iod
s a ing in 1994 and a e exp essed in USD pe on.
The unc ion used by he @Risk 8.2 so wa e was RiskARCH1 (
μ
,
ω
,
b
1
, Y
0
), which "gene a es a i s -o de au o eg essi e condi ional he e o-
scedas ici y p ocess" (PALISADE, 2023) and is ecommended o p e-
dic ing he u u e p ice o commodi ies. The ope a ion o his unc ion is
exp essed in Eqs. (4) and 5, which a e p esen ed below:
Eq. (4). F om Palisade, 2023
Y =
μ
+
σ
N (4)
When
σ
is modeled as ollows:
σ
2
=
ω
+a1(Y −1−
μ
)
And:
N : is a no mal dis ibu ion unc ion (0,1)
μ
=37,239 (a e age)
ω
=244,3 ( a iance equa ion cons an )
b
1
=0,57,735 (coe icien o e o ),
Y
0
=46 ( ime alue 0)
In Figs. 13 and 14 i is possible o see he beha io o he p ojec ions
made, and he dis ibu ion unc ion in which he 25 h (P 25) and 75 h (P
75) pe cen iles a e iden i ied, wi h hei espec i e alues.
In he g aphs shown, i is possible o iden i y ha o he 25 h (P25)
and 75 h (P75) pe cen iles, he alues a e 26.6 USD/ and 47.9 USD/ ,
espec i ely. In he case o he 50 h pe cen ile (P50), his co esponds o
he mean o he unc ion, which was 37.24 USD/ . These alues we e
conside ed o pe o ming he sensi i i y analysis, whe e he coal p ice
will essen ially eplace he alue in he economic alua ion o he mine
sequencing. I is impo an o emphasize ha , o educe he amoun o
da a, only he ele an esul s om he iden i ied scena ios will be
shown ( o al mine al ex ac ed, o al was e ex ac ed, accumula ed NPV,
LOM, and was e- o-mine al a io). Table 8 p esen s he esul s o he
sensi i i y analysis wi h he h ee p oposed scena ios.
The sensi i i y analysis conduc ed on he coal p ice indica es ha he
p ojec is ulne able o d as ic changes i low mine al p ices a e
conside ed. The scena ios o he 25 h and 50 h pe cen iles sugges ha
he e is a possibili y ha he p ojec may no be iable unde he con-
di ions p oposed, no so much due o he NPV, as bo h cases a e abo e 0,
bu a he due o he sho mining li e. Wi h such low p ices, he so -
wa e algo i hm only inds mine al ex ac ion o be p o i able o pe iods
o 2 and 5 yea s, espec i ely. Such sho LOMs a e no easible due o
he la ge in es men s equi ed o s a a p ojec , which we e no
accoun ed o in his a icle (e.g., equipmen acquisi ion, acili y con-
s uc ion, pe sonnel hi ing, geological s udies, e c.).
The 75 h pe cen ile scena io is no shown in Table 8, as he so wa e
could no sequence he mined blocks wi h a highe cos . This was no
due o p o i abili y conce ns, bu a he because, unde he gi en con-
di ions, ex ac ion capaci ies o pe iods need o be inc eased o ind he
op imal solu ion, which could undoub edly lead o a highe NPV.
Howe e , inc easing ex ac ion a es, LOM, o changing o he e-
s ic ions would make i impossible o compa e wi h he case s udy, as i
would ep esen a comple ely di e en p ojec wi h o he associa ed
en i onmen al cos s, which would be inco ec o compa e.
Conside ing ha p ojec s wi h lowe ex ac ion a es and sho e
LOMs equi e smalle ini ial in es men s, we can conclude ha wi h
lowe p ices, i is possible o p opose smalle -scale p oduc i e al e na-
i es ha may s ill be p o i able. Simila ly, as shown in he 75 h
pe cen ile scena io, i would be necessa y o inc ease he es ic ion on
ex ac ion a es in o de o achie e a p ojec ha aligns wi h he ma-
e ial handling capaci y equi emen s.
Fig. 13. P ice p ojec ions using @Risk 8.2 so wa e.
Fig. 14. P ice p ojec ion dis ibu ion unc ion.
Table 8
Resul s o p ice sensi i i y analysis.
Case B Scene y
P25
Scene y
P50
Scene y
P75
Mine al Ex ac ed (M ) 251,57 22,65 63,89 *
Was e Ex ac ed (M ) 1.970,74 135 580,61 *
NPV Accumula ed (M
USD)
898,30 178,43 331,20 *
LOM (yea s) 17 2 5 *
Was e/mine al a io 7,84 7,87 9,1 *
D. Oli e os-Sepúl eda e al.
The Ex ac i e Indus ies and Socie y 23 (2025) 101668
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