Evaluation of geothermal potential in the vicinity of the flooded Sierra Almagrera Mines (Almeria, SE Spain)

UPCommons Po al del coneixemen obe de la UPC h p://upcommons.upc.edu/e-p in s Aques a és una còpia de la e sió au ho ’s inal d a d'un a icle publica a la e is a Mine wa e and en i onmen . La publicació inal es à disponible a Sp inge a a és de h p://dx.doi.o g/10.1007/s10230-017-0478-9 This is a copy o he au ho 's inal d a e sion o an a icle published in he jou nal Mine wa e and en i onmen . The inal publica ion is a ailable a Sp inge ia h p:// dx.doi.o g/10.1007/s10230-017-0478-9 A icle publica / Published a icle: Na a o, A.F., Ca ulla, N. (2017) E alua ion o geo he mal po en ial in he icini y o he looded Sie a Almag e a Mines (Alme ia, SE Spain). "Mine wa e and en i onmen ". Vol. 37, núm. 1, pp.137-150. Doi: 10.1007/s10230-017-0478-9 UNCORRECTED PROOF Jou nal : La ge 10230 A icle No : 478 Pages : 14 MS Code : MWEN-D-16-00167 Dispa ch : 29-7-2017 Vol.:(0123456789) 1 3 Mine Wa e En i on DOI 10.1007/s10230-017-0478-9 TECHNICAL ARTICLE E alua ion o Geo he mal Po en ial in heVicini y o  heFlooded Sie a Almag e a Mines (Alme ia, SE Spain) And ésNa a o1· Na císCa ulla2 Recei ed: 7 No embe 2016 / Accep ed: 24 July 2017 © Sp inge -Ve lag GmbH Ge many 2017 In oduc ion Flooded unde g ound mines may cons i u e a po en ial geo- he mal esou ce o low- empe a u e uses (Raymond and The ien 2008; Wang e al. 2016; Wolke sdo e 2008), o e en o elec ici y p oduc ion, i he ese oi has a su - ficien ly high empe a u e. The closu e o deep abandoned mines in ol es he cessa ion o he expensi e pumping sys- ems and he p og essi e g oundwa e ebound can cause anspo o con aminan s and ene gy. In hese cases, he mine wa e may be a sou ce o enewable ene gy (Banks e  al. 1997; Younge 2013) and hei hyd ogeochemis- y may be use ul in de e mining i s o igin and na u e (Younge e al. 2015). Thus, he use o mine wa e o geo he mal pu poses may p o ide an inno a i e oppo uni y o ex ac low- g ade geo he mal ene gy (Janson e al. 2009; Ja dón e al. 2013; K anz and Dillena d 2010; Wa zla and Ackman 2006). Fu he mo e, he he mal ene gy po en ial o mine wa e may be es ima ed using ma hema ical models, which esol e hea , flow, and mass anspo equa ions in o de o es ima e he po en ial efficiency o geo he mal mine wa e applica ions (Lo edo e al. 2016). In ha sense, he geo he mal po en ial o some flooded mines has been assessed using diffe en nume ical codes (Hamm and Sabe 2010; Renz e al. 2009; Uhlík and Baie 2012). When deep flooded unde g ound mines a e loca ed in anomalous geo- he mal a eas, he po en ial use o he mine wa e o geo- he mal ene gy p oduc ion may be o in e es . The po en ial o his may be ex ended o he en i e g oundwa e sys em i he use o geo he mome e s o o he geochemical ech- niques indica e ele a ed equilib ium empe a u es in he possible ese oi . The mine al ein deposi s mined in he Sie a Almag e a a e mainly made up o galena, ba i e, side i e, and Ag-Pb Abs ac We e alua ed he hyd ogeochemical cha ac e - is ics o wa e om he old flooded Sie a Almag e a mines o de e mine he possible o igin o i s geo he mal fluids, o es ablish a geological–geochemical model o he geo he - mal sys em, and e alua e he si e’s geo he mal po en ial. The mine wa e con ained high concen a ions o chlo ide (59.6 g/L), Na (28 g/L), K (1.75 g/L), Ca (7.2 g/L), Mg (0.63g/L), and Li (66mg/L), especially in wa e om he old dewa e ing sys em. Me al concen a ions we e espe- cially ele a ed in he old mine sha s, wi h high amoun s o Fe (1990 mg/L), Mn (600 mg/L), Zn (460 mg/L), Pb (4mg/L), and Ni (11.4mg/L). The Cl/B mola a ios o he wa e was high, which may indica e he possible leaching o na u al hali e om he e apo i e deposi s in he aqui e echa ge a ea. The mine wa e had he mos ele a ed em- pe a u es and a e, possibly, ep esen a i e o he ex en o equilib a ion in mos o he ese oi . The es ima ed mean empe a u es in he geo he mal ese oi , based on he i- angula (Giggenbach) Na–K–Mg diag am, was 190°C o equilib a ed wa e s, which may jus i y he de elopmen o his geo he mal esou ce. The geo he mal cha ac e is ics imply con ec ion o g oundwa e o 2500–3000 m below sea le el, in ag eemen wi h he hyd odynamic model p oposed. Keywo ds Mine wa e · Geo he mome e · Saline g oundwa e · Hyd ogeochemis y  And és Na a o na[email p o ec ed] 1 Depa men o Fluid Mechanics, Uni e si a Poli ècnica de Ca alunya, Colón 7–11, 08222Te assa, Spain 2 Geólogos Aseso es, E es 6, Al a ulla, 43893Ta agona, Spain AQ1 1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 20 21 22 23 24 25 26 27 28 29 30 31 32 33 34 35 36 37 38 39 40 41 42 43 44 45 46 47 48 49 50 51 52 53 54 55 56 57 58 59 60 61 62 63 64 65 66 A1 A2 A3 A4 A5 A6 UNCORRECTED PROOF Jou nal : La ge 10230 A icle No : 478 Pages : 14 MS Code : MWEN-D-16-00167 Dispa ch : 29-7-2017 Mine Wa e En i on 1 3 sul osal s (Ezque a del Bayo 1844). In he nine een h cen- u y, abou 45 polyme allic eins (0.15–7 m hick) we e in ensi ely exploi ed down o 180m below sea le el, which was he maximum dep h allowed by he a ailable g ound- wa e pumping sys em. Mining declined in he ea ly wen- ie h cen u y and was discon inued a he beginning o he Spanish Ci il Wa . Selec i e unde g ound mining o high g ade lead-sil e eins was eini ia ed in 1945 by he s a e-owned company MASA (Minas de Almag e a, S.A.) and ceased in 1957, when he exploi a ion le el eached 220m below sea le el and mining cos s inc eased d ama i- cally (Na a o and Ma ínez 2010). Me al p oduc ion in he Sie a Almag e a mining dis ic du ing he mos p o- duc i e pe iod (be ween 1841 and 1912) was es ima ed a app oxima ely 500,000 o Pb and 3000 o Ag (Na a o 2016; Na a o e al. 2008). The geo he mal fluid was used du ing he mode n exploi a ion in a since abandoned spa, loca ed close he dewa e ing sys em in he A eal a ea. An expe imen al deep well (EDW) was buil in 1983 o e alu- a e he easibili y o li hium exploi a ion om he geo he - mal fluids, by Peña oya Mining Co., al hough he esul s we e nega i e. The objec i es o his s udy we e o e alua e he hyd o- geochemical cha ac e is ics o he Sie a Almag e a mine wa e and de e mine he possible o igin o i s geo he mal fluids. In addi ion, he geochemical signa u es o he com- piled analysis we e used o es ablish a geological–geo- chemical model o he geo he mal sys em and e alua e i s geo he mal po en ial. S udy A ea Geological Se ing Sie a Almag e a is loca ed in he Be ic ange (SE Spain), and is associa ed wi h he in e nal zone o he Albo án domain (Fig.1). The Be ic ange esul s om he con e - gence be ween A ica and Eu asia pla es since Eocene, and o ms an alpine ec onic wedge ha eaches a hick- ness o abou 60km (Dyja 2014). The in e nal Albo án domain may be di ided in o h ee main ec ono-me a- mo phic zones om he bo om o op: Ne ado-Filáb ide Fig. 1 Si ua ion and simplified geologic map, modified om López e  al. (1993): A Volcanic ocks (Neogene), B Neogene-Qua e na y sedimen s, C Alpujá ide complex, D Béda -Macael uni (Ne ado- Filáb ide complex), E Cala Al o uni (Ne ado-Filáb ide complex), PF Paloma es Faul , TERR Te e os own, hp hyd o he mal p ecipi- a es. Expe imen al deep well and old mine sha s: 1 A eal mine dewa e ing sys em (A1–A7, A18–A20 samples). 3 (EDW) Expe i- men al deep well (A24–A38, A42–A44 samples). 4 (DCP) Deep coas al piezome e buil in 2009 (DCP sample). 5 Glo ia mine sha (A22, A40 samples). 6 (CA): The mal wa e nea Te e os own (CA sample). 7 Guzmana mine sha (A12–A15, A21, A41 samples). 8 Ramo de flo es mine sha (A8–A11, A23, A39 samples) 67 68 69 70 71 72 73 74 75 76 77 78 79 80 81 82 83 84 85 86 87 88 89 90 91 92 93 94 95 96 97 98 99 100 101 102 103 104 105 UNCORRECTED PROOF Jou nal : La ge 10230 A icle No : 478 Pages : 14 MS Code : MWEN-D-16-00167 Dispa ch : 29-7-2017 Mine Wa e En i on 1 3 (Ragua, Cala Al o and Béda -Macael uni s), Alpujá ide, and Maláguide nappes. The co e o Sie a Almag e a consis s o he lowe li hologic Be ic domain, called he Ne ado-Filáb ide Complex (Boo h-Rea e  al. 2004), which lies below he Alpujá ide Complex (C in Figs. 1, 2). These s a a mainly comp ise black schis s and qua zi es app oxi- ma ely 800 m hick, me a ulcani es, and black mica- ceous ma ble loca ed in he highes pa o he se ies. This me amo phic uni is associa ed wi h Cala Al o uni (E in Figs.1, 2) and is Paleozoic in age, wi h he ma ble deposi ed in he Middle De onian. The Alpujá ide Complex consis s o g aphi ic phyl- li es and schis s and an e apo i ic uni in he Sie a de Almag o a ea, which comp ise a hick sequence (600m) o ca bona es and e apo i es (Fig. 2). Disco dan sedi- men a y ma e ials o Neogene age a e loca ed a ound Sie a Almag e a (B in Figs. 1, 2). In he uppe pa (Salme ón o ma ion), he sedimen s a e cha ac e ized by up o 60 m o in e bedded successions o ed conglom- e a es, sands ones, sil s ones, muds ones, and e apo i es (S okes 2008). Qua e na y allu ial deposi s comp ise g a el and sandy beds ha a e app oxima ely 30–40 m hick. They a e i egula ly dis ibu ed in allu ial e aces, associa ed wi h he Almanzo a Ri e and ibu a ies, such as Canalejas C eek. Volcanic neogenic ocks (A in Figs. 1, 2), belonging o he NVPS (Neogenic olcanic p o ince o SE Spain), lie along he wes e n and eas e n bo de o Sie a Alma- g e a, wi h a s uc u e con olled by ac u es. Since la e Miocene, ex ensional and anscu en ec onics ha e affec ed he me amo phic co es and sedimen a y co - e s in his egion, p oducing a sys em o ac u es N 40–60 E and N 10–20 E, pa allel o he Paloma es aul (Figs.1, 2). The ec onics also con ibu ed o he o ma- ion o anges sepa a ed by basins filled con inen al and/ o ma ine sedimen s. The magmas may be associa ed wi h he Middle o Uppe -Miocene ex ensional collapse o he o e - hickened o ogenic wedge and he ex usion o domes, sills, and necks h ough high-angle no mal aul s, dis up ing he uppe - pla e o he de achmen sys ems (Beni o e al. 1999). In he eas e n pa o he Sie a Almag e a, close o he NE bo - de nea he Medi e anean Sea, he ou c opping olcanic ma e ials consis o sills and dykes ela ed o he main ac- u ed sys ems and cha ac e ized by shoshoni ic (banaki es and oscani es) and ul apo assic se ies (Al a ez 1991). Vein deposi s exploi ed in Sie a Almag e a may be con- side ed as epi he mal o “in e media e sulfida ion” (Cam- p ubí and Albinson 2006). The o e deposi s a e cha ac e - ized by o e bodies ha do no ou c op a he su ace. O ema kable in e es is he p esence o su ace siliceous o - ma ions (sin e s) in he Te e os a ea and he coas al bo de o Sie a Almag e a (hp samples in Fig.1), associa ed wi h he su ace discha ge o Plio-Qua e na y geo he mal fluids. Clima ology andHyd ogeology The s udy a ea has an a id clima e wi h an a e age annual p ecipi a ion o 200mm, wi h he excep ion o he Sie a de Almag o a ea whe e annual p ecipi a ion exceeds 250mm, and an epheme al su ace unoff, which can be conside - able, since 50% o he annual p ecipi a ion can all in a ew days (Na a o and Ma ínez 2010). The main aqui e s in he a ea o Sie a Almag e a a e he ac u ed me amo - phic geo he mal sys em and he Canalejas allu ial aqui e , Fig. 2 Hypo he ical P–Pƍ (NW–SE) sec ion ac oss he geo he mal sys em, based on De Sie a (1928): A Volcanic ocks (Neogene); B Neogene- Qua e na y sedimen s; C Alpujá ide complex; D Béda - Macael uni (Ne ado-Filáb ide complex); E Cala Al o uni (Ne ado-Filáb ide complex); GW Regional g oundwa e flow; PF Paloma es Faul 106 107 108 109 110 111 112 113 114 115 116 117 118 119 120 121 122 123 124 125 126 127 128 129 130 131 132 133 134 135 136 137 138 139 140 141 142 143 144 145 146 147 148 149 150 151 152 153 154 155 156 157 158 159 160 161 162 163 164 165 166 167 168 169 UNCORRECTED PROOF Jou nal : La ge 10230 A icle No : 478 Pages : 14 MS Code : MWEN-D-16-00167 Dispa ch : 29-7-2017 Mine Wa e En i on 1 3 a ibu a y o he Almanzo a Ri e . The geo he mal sys em is a low-pe meabili y aqui e , associa ed wi h a ac u ed me amo phic ne wo k (schis s and phylli es), which had o be con olled du ing he ac i e li e o he mines. Indeed, mining o he deepe o e bodies needed o ex ac app oxi- ma ely 15,000 m3/day, wi h inc easing empe a u es wi h dep h. The main de-wa e ing sys em comp ised wo deep wells loca ed in he A eal a ea (Fig.1) connec ed wi h gal- le ies ha we e 332 m in leng h and d ained mine wa e om app oxima ely 220 m deep. Al hough he aqui e ends o be highly he e ogeneous and has ela i ely low al- ues o hyd aulic conduc i i y and ansmissi i y, he alues p o ided by his o ical da a om pumping assays showed a mac oscopic ansmissi i y be ween 180 and 255m2/day. The o igin o he he mal wa e s was dispu ed o many yea s be ween he suppo e s o a ma ine o con inen al o igin o geo he mal wa e s (De Sie a 1928; Gomez I ib- a ne 1908; Sou i on 1898). The egional g oundwa e flow seems associa ed wi h he basin and ange sys em, whe e he echa ge is loca ed in high elie a eas o Sie a de Almag o and, possibly, in he coas al a ea, whe e a mino olume o sea wa e may infil a e (Fig.2). His o ical mine wa e analysis ob ained om old mining ope a o s and he dewa e ing socie y o Sie a Almag e a, and pumping assays ound be ween 1983 and 1985 (Ca ulla 2012) a e all scien ifically impo an since he dewa e ing sys em no longe exis s and he deep expe imen al well d illed in 1983 is no accessible. Ma e ials andMe hods His o ical mine wa e analyses we e ob ained o he A eal dewa e ing sys em, old mine sha s and EDW. Wa e sam- ples we e collec ed o analysis om sea wa e and a deep coas al piezome e (130m) d illed close o he sho eline and geo he mal wells nea he own o Te e os (DCP in Fig.1). In he p esen wa e samples, he pH, edox po en ial (Eh; mV), empe a u e, and elec ical conduc i i y (EC; μS/ cm) we e measu ed in si u wi h po able de ices (HACH sensIONTM378) a e app op ia e calib a ion and co ec- ion using s anda d solu ions. Wa e samples we e also fil- e ed wi h a cellulose ni a e memb ane wi h a po e size o 0.45 μm. Samples o ca ion analysis we e la e acidi- fied o pH < 2.0 by adding ul a-pu e HNO3. The samples we e collec ed in 110mL high-densi y polyp opylene bo - les, sealed wi h a double cap, and e ige a ed un il analy- sis. The g oundwa e samples we e ob ained a e pu ging, using a baile sample and subme sible pumps. Me al concen a ions we e measu ed by induc i ely coupled plasma-mass spec ome y (ICP-MS) in he Ac labs labo a o ies. The concen a ions o chlo ide, ni a e, and sulpha e (in a second un ea ed sample) we e analyzed by ion ch oma og aphy. The alkalini y o he wa e s was de e mined by i a ion. The NIST s anda d e e ence ma e ial 1640 (ICP-MS) was used o confi m accu acy. Geochemis ´s Wo kbench 9.0 (Be hke and Yeakel 2011) was used o e alua e he specia ion o dis- sol ed cons i uen s and calcula e he sa u a ion s a e o mine al phases in he wa e samples. The hyd o he mal p ecipi a es and hos ock (me a- mo phic and olcanic ocks) we e manually ex ac ed o ob ain samples o app oxima ely 1.5 kg. Solid samples we e passed h ough a jaw c ushe o a pa icle size o en mesh, qua e ed, pul e ized in an aga e mo a , e- homogenized, and e-packed in plas ic bags. Au, Ag, As, Ba, B , Ca, Ce, Co, C , Cs, Eu, Fe, H , Hg, I , La, Lu, Na, Ni, Nd, Rb, Sb, Sc, Se, Sm, Sn, S , Ta, Th, Tb, U, W, Y, and Yb we e quan i a i ely analyzed by ins umen al neu on ac i a ion analysis (INAA), which in ol es bom- ba ding he unal e ed samples wi h neu ons. Mo, Cu, Pb, Zn, Ag, Ni, Mn, S , Cd, Bi, V, Ca, P, Mg, Tl, Al, K, Y, and Be we e analyzed using induc i ely coupled plasma op ical emission spec ome y (ICP-OES). These analy- ses used a nea - o al diges ion, employing HF, HClO4, HNO3, and HCl o ge as much o he sample in o solu- ion as possible; he esul ing me als we e de e mined by ICP-OES in Ac labs (On a io, Canada). Resul s Chemis y o B ines andG oundwa e Chemical analyses showed a Na-Ca chlo ide dominan acies, wi h a Cl con en ha eached 59.6 g/L, which Table 1 Hyd ogeochemical da a o 1906 (A1), 1933 (A2) and 1950 (A3) El A eal mine dewa e ing sys em. A1 da a om Gómez I iba ne (1908), A2 da a om Ca ulla (2012), A3 da a om Ca ulla (pe sonal communica ion). Concen a ions a e in g/L Pa ame e A1 A2 A3 Piezome ic head (m) −146m −160m ND Tempe a u e (ºC) 50.5 55.3 49.0 Ca 4.29 6.07 3.2 K <0.01 2.51 1.125 Mg 0.576 0.664 1.38 Na 20.5 24.03 16.97 Cl 35.74 45.57 36.8 SO40.948 1.057 1.27 HCO30.063 <0.01 <0.01 Fe 0.043 0.055 0.08 Li ND 0.054 0.0875 To al salini y 66.61 86.10 68.45 AQ2 170 171 172 173 174 175 176 177 178 179 180 181 182 183 184 185 186 187 188 189 190 191 192 193 194 195 196 197 198 199 200 201 202 203 204 205 206 207 208 209 210 211 212 213 214 215 216 217 218 219 220 221 222 223 224 225 226 227 228 229 230 231 232 233 234 235 236 237 238 239 240 241 242 243 244 245 246 247 248 UNCORRECTED PROOF Jou nal : La ge 10230 A icle No : 478 Pages : 14 MS Code : MWEN-D-16-00167 Dispa ch : 29-7-2017 Mine Wa e En i on 1 3 exceeds ha o he Medi e anean Sea (Tables1, 2, 3, 4, 5). Na–Cl and Na–Ca–Cl we e he dominan wa e ype o he mal wa e s, wi h e y high concen a ions o Na, K, Ca, Mg, and Li, especially in wa e s om pumping assays (Tables 4, 5). High sal concen a ions a e qui e a e in geological en i onmen s unless magma ic b ines o e apo- i es a e p esen (Ingeb i sen e al. 2008). The mos saline geo he mal wa e s a e associa ed wi h geo he mal b ines Table 2 Hyd ogeochemical da a o May 1971 El A eal mine dewa e ing (A4–A7), Ramo de Flo es mine sha (A8–A11) and Guzmana mine sha (A12–A15). Da a om Ca ulla (2012) Pa ame e A4 A5 A6 A7 A8 A9 A10 A11 A12 A13 A14 A15 Piezome ic head (m) −75 −122 −167 −212 −86 −118 −137 −164 −78 −98 −126 −150 pH, T (°C) 7.3, 33 6.8, 33 6.9, 33 6.8, 33 3.6, 35 4, 34 3.6, 34 3.6, 34 2.9, 30 2.9, 28 2.9, 32 3.0, 32 Salini y (g/L) (110°) 10,340 10,260 10,210 10,410 38,550 38,870 40,460 38,920 24,670 25,130 29,560 34,080 Salini y (g/L) (160°) 6260 7120 5890 6950 29,600 26,910 28,470 29,560 17,680 17,230 20,780 22,880 HCO3 (mg/L) 271 277 283 265 0 0 0 0 0 0 0 0 Cl (mg/L) 3430 3342 3410 3094 17,255 17,459 17,118 16,436 8593 8252 10,162 10,912 SO4 (mg/L) 3250 2750 3275 3575 4225 4075 4300 4300 7825 7575 8500 8600 B (mg/L) 4.65 2.85 3.9 4.45 3.25 3.05 3.05 3.7 2.45 1.8 2.8 2.35 Si (mg/L) 4 3 4 2 2 2 2 2 2 2 2 2 Ca (mg/L) 616 608 648 624 1488 1480 1400 1568 312 240 400 376 Mg (mg/L) 267 282 282 272 1026 1075 1035 1021 1249 1244 1307 1589 Na (mg/L) 2650 2450 2450 2450 9750 8950 9150 8586 4300 4450 5350 6500 K (mg/L) 141 147 134 119 690 630 670 570 187 197 228 350 Li (mg/L) 5.5 5.5 6 5.5 27 27.5 27 26.3 13.2 13.2 16.7 18.7 Fe (mg/L) 0.2 0.5 1.9 0.7 157 119 206 216 1270 1400 1250 1610 Table 3 Hyd ogeochemical da a o 1973 (17-07-73/07-08- 73) (*) El A eal mine dewa e ing sys em. (1) Guzmana old mine sha , (2) Glo ia old mine sha , (3) Ramo de Flo es old mine sha . Da a om Ca ulla (2012) Pa ame e A18 (*) A19 (*) A20 (*) A21 (1) A22 (2) A23 (3) Piezome ic head (m) −71.3 −121.3 −171.3 −149.5 −96.5 −144 Tempe a u e (°C) 32 32.5 35 46 44.5 46.5 Cl (mg/L) 3600 3600 3800 7600 10,400 13,200 SO4 (mg/L) 2595 2400 2500 6720 8300 4180 F (mg/L) 1.8 3.6 2.1 3.4 4.2 3.9 Si (mg/L) 5.25 6.0 1.7 1 1 1.4 Ca (mg/L) 610 630 830 750 1700 660 Mg (mg/L) 290 290 1180 890 800 300 Na (mg/L) 1800 2100 1700 16,600 6000 7500 K (mg/L) 140 160 160 265 470 565 Li (mg/L) 6.8 6.8 6.4 12 20 20 Fe (mg/L) 1 1.78 17.2 1580 1990 398 Mn (mg/L) 15 1 1 380 600 250 Zn (mg/L) 1.6 1.2 2.3 460 360 130 Cu (mg/L) 1.5 1.8 1.7 12 1 1.4 Ba (μg/L) 15 18 18 12 15 14 Pb (μg/L) 50 50 50 3500 3000 4000 Ti (μg/L) 50 50 50 50 50 50 Z (μg/L) 50 50 50 50 50 50 P (μg/L) 50 50 50 50 50 50 As (μg/L) 55 55 55 350 200 400 Ni (μg/L) 50 60 60 1200 1000 11,400 AQ3 249 250 251 252 253 254 255 256 UNCORRECTED PROOF Jou nal : La ge 10230 A icle No : 478 Pages : 14 MS Code : MWEN-D-16-00167 Dispa ch : 29-7-2017 Mine Wa e En i on 1 3 de i ed om g oundwa e dissolu ion o e apo i es, sub- su ace hyd o he mal me amo phism, and su ace e apo- a ion, such as he Sal on Sea geo he mal sys em (McKib- ben e al. 1987; Mazzini e al. 2011), o g oundwa e flow mixing wi h saline b ines (Fa be e al. 2007; Younge e al. 2015). In addi ion, ele a ed concen a ions o me als we e de ec ed in he old mine sha s (Table 3), showing high amoun s o Fe, Mn, Zn, Pb, and Ni, due o me al mobiliza- ion om he ein deposi s, by sulphide oxida ion, and dis- solu ion o efflo escen sal s. The Pipe diag am (Fig.3) shows he Na–Cl dominan cha ac e o he he mal samples, which plo in a na ow field, wi h he excep ion o he low empe a u e samples om he old mine sha s and he seawa e and coas al wa e samples (Tables6). A plo o he Cl/B mola a io s. Cl (in mg/L) showed a high Cl/B mola a io (1564–12,879) (Fig.4), which may indica e he leaching o na u al hali e and/o Mesozoic hali e dissolu ion (Alcalá and Cus odio 2008), om he e apo i e deposi s loca ed in he aqui e echa ge a ea. Fu he mo e, he he mal wa e samples ha e Cl/B a ios highe han hose o seawa e , indica ing ha he high salini y was no associa ed wi h ma ine wa e . How- e e , possible mixing o hali e-leaching b ines wi h a small amoun o sea wa e could p oduce a salini y simila o ha de ec ed in he geo he mal fluids. The o igin o he salini y may be indica ed by a bi a i- a e plo o he Cl/Na a io (Fig.5). Dissolu ion o hali e o dilu ion o hali e b ines p oduces wa e o ela i ely uni- o m chemical composi ion, as indica ed in Fig. 5, whe e plo s o Na con en s o wa e samples s. Cl concen a ion showed a co ela ion coefficien o 0.91. In ac , he Alma- g o and Almanzo a uni s associa ed wi h he Alpujá ide Complex (Fig. 2) con ain wo me a-e apo i e sequences 600 and 200m hick, espec i ely, domina ed by he p es- ence o gypsum and o he e apo i ic ocks. Fu he mo e, in he e ia y sedimen s ha filled he Ve a basin (Fig.2), he p esence o 5–10m hick e apo i es is also equen ly Table 4 Hyd ogeochemical da a o 1983 Da a om Ca ulla (2012) EDW expe imen al deep well, FR flow a e, TDS o al dissol ed sol- ids Pa ame e A24 A25 A26 A38 Day 18–01 23–01 28–01 23–03 Dynamic piezome ic head (m) −176.8 −173 −173 −195 D awdown (m) 7 3 3 25 Tempe a u e (°C) 51.0 51.0 51.0 51.0 FR (L/s) 15 15 15 45 TDS (g/L) 103 103 103 100 pH 6.8 6.9 6.9 6 Cl (g/L) 58.9 59.3 59.6 57.5 SO4 (g/L) 0.82 0.89 0.95 1.01 Na (g/L) 28.2 28 28 27.4 K (g/L) 1.7 1.7 1.7 1.75 Ca (g/L) 7.2 7 7.06 6.75 Mg (g/L) 0.6 0.63 0.63 0.6 Li (mg/L) 65 65 65 66 Fe (mg/L) 48 47 32 33 Zn (mg/L) 2 1 1 1 In (mg/L) 0.9 1 1 0.8 Si (mg/L) 6.5 5 5 7.1 Table 5 Hyd ogeochemical da a o old mine sha s (OMS) and expe imen al deep well (EDW) Da a o 1986. Da a om Ca ulla (2012) Sample A39 (RAMO DE FLORES) (OMS) A40 (GLORIA) (OMS) A41 (GUZ- MANA) (OMS) A42–A43–A44 EDW (550m dep h) Topog aphic le el (m) 246.96 223.33 249.53 103.86 Dynamic piezome ic head (m) −52.5 −49.76 −49.59 −58.41 Sampling piezome ic head (m) 390 300 420 200 350 500 Absolu e piezome ic head (m) −143 −76 −170.5 −96 −246 −396 TDS (g/L) 33.7 33.73 27.6 93.37 94.4 92.45 Cl (g/L) 16.33 12.07 9.95 52.9 53.6 53.6 SO4 (g/L) 4.2 8.6 7.55 0.77 0.69 0.68 Na (g/L) 7.05 5.25 4.25 24 23.3 23.3 K (g/L) 0.57 0.42 0.32 2.05 2.2 1.9 Ca (g/L) 1.65 0.95 0.85 8.5 8.6 9 Mg (g/L) 0.95 1.2 1.05 0.7 0.7 0.69 Li (mg/L) 21.3 18 12.8 67 67.5 67.3 257 258 259 260 261 262 263 264 265 266 267 268 269 270 271 272 273 274 275 276 277 278 279 280 281 282 283 284 285 286 287 288 289 290 291 292 293 294 295 UNCORRECTED PROOF Jou nal : La ge 10230 A icle No : 478 Pages : 14 MS Code : MWEN-D-16-00167 Dispa ch : 29-7-2017 Mine Wa e En i on 1 3 associa ed wi h massi e and/o bedded/lamina ed beds (S okes 2008). The s able iso ope da a o he he mal wa e showed li - le δO18 a iance, anging om −5.3 o −5.0‰ (Ca ulla 2012). Gas geochemis y showed ha he ca bon iso opic δC13 composi ions om CO2 ange om −8.1 o −3.8‰ (Ce ón e  al. 2000), which exceeds he ypical ange o CO2 de i ed om magma ic sou ces (−6.0 o −3.0‰; Mazzini e  al. 2011) and he mal deca bona ion eac ions (−5.0 o +4.0‰). This sugges s ha he flowing wa e may comp ise a combina ion o hali e dissolu ion and dilu ion by me eo ic wa e s, and possibly mino amoun s o sea wa e infil a ion in he coas al a ea. Da a om pumping assays may ep esen he deep geo he mal sys em (samples A24–A38 in Table 4 and samples A42–A44 in Table 5), while wa e om he old mine sha s may be a mix u e o geo he mal and supe ficial wa e associa ed wi h echa ge. G oundwa e Specia ion andMine al Equilib ium Mine al sa u a ion was de e mined o he mos ep e- sen a i e he mal wa e s using Geochemis ’s Wo bench 9.0 (Be hke and Yeakel 2011). Mine als wi h a sa u a ion index (SI) be ween −1 and 1 likely con ol he makeup o Fig. 3 Pipe diag am o mos ep esen a i e samples: A1 hyd o- geochemical da a om 1906 (El A eal mine dewa e ing sys em), A2 hyd ogeochemical da a om 1933 (El A eal mine dewa e - ing sys em), A3 hyd ogeochemical da a om 1950 (El A eal mine dewa e ing sys em), A4 hyd ogeochemical da a om 1971 (El A eal mine dewa e ing sys em), A20 hyd ogeochemical da a om 1973 (El A eal mine dewa e ing sys em), A21 hyd ogeochemical da a om 1973 (Guzmana old mine sha ), A22 hyd ogeochemical da a om 1973 (Glo ia old mine sha ), A23 hyd ogeochemical da a om 1973 (Ramo de Flo es old mine sha ), A24 hyd ogeochemical da a om 1983 (EDW: expe imen al deep well), A25 hyd ogeochemical da a om 1983 (EDW: expe imen al deep well), A38 hyd ogeochemical da a om 1983 (EDW: expe imen al deep well), A44 hyd ogeochemi- cal da a om 1986 (EDW: expe imen al deep well), DCP hyd ogeo- chemical da a om 2009 (deep coas al piezome e ), SEA hyd ogeo- chemical da a om sea wa e 296 297 298 299 300 301 302 303 304 305 306 307 308 309 310 311 312 313 314 315 316 317 UNCORRECTED PROOF Jou nal : La ge 10230 A icle No : 478 Pages : 14 MS Code : MWEN-D-16-00167 Dispa ch : 29-7-2017 Mine Wa e En i on 1 3 Table 6 Resul s o wa e sampling: p esen hyd ogeochemical da a o Medi e anean Sea, deep coas al piezome e (DCP), he mal wa e o Te - e os a ea (CA) and El A eal mine dewa e ing Analysis om Ac labs (On a io, Canada) C elec ical conduc i i y (μS/cm), Eh mV, T empe a u e (°C), ND no de e mined Pa ame e C Eh pH O2T F Cl NO2 (as N) B NO3 (as N) PO4 (as P) SO4HCO3 Uni μS/cm mV mg/L °C mg/L mg/L mg/L mg/L mg/L mg/L mg/L mg/L Anions in mg/L DCP 43,700 −109 6.84 3.45 19.0 <2 13,400 <2 45 <2 <3 2070 207 SEA 66,100 74 8.17 8.5 18.0 <2 19,900 <2 65 <2 <5 2750 120 CA 5760 55 7.74 7.77 19.8 <0.2 410 <0.2 <0.6 <0.2 <0.4 1490 360 A eal 9400 500 7.22 ND 29.3 <0.01 2265 <0.01 ND <0.01 4.2 1987 294 Pa ame e Na Li Mg Si K Ca Mn Fe Ni Cu Zn As Pb Th U Uni s mg/L μg/L mg/L mg/L mg/L mg/L μg/L μg/L μg/L μg/L μg/L μg/L μg/L μg/L μg/L Me als and semime als in μg/L DCP 1000 200 1040 <20 341 420 2800 4000 250 120 130 33 22 <0.1 1.3 SEA 1000 200 1530 <20 474 520 <10 <1000 480 150 80 <3 4 <0.1 3.6 CA 614 500 215 <20 20 320 <10 <1000 60 420 630 <3 39 <0.1 29.7 A eal 1122 1700 244.9 10.1 77 502 1350 170 240 240 1260 ND 670 ND ND Fig. 4 Bi a ia e plo o ela ionship Cl/B (mol) e sus Cl (mg/L)