Mine Waste: Pollution Source or Georesource?

Transcription

1 Mine Waste: Pollution Source or Georesource? Bernhard Dold

2 Escondida, Chile Tailings impoundment Waste dumps Open pit

3 Cerro de Pasco, Perú Acid Mine Drainage (AMD) Acid Rock Drainage (ARD) Acid Drainage (AD) Neutral Mine Waters (NMW)

4 Bahía de Ite, Perú Dold et al. (2011)

5 Exotica, Chuquicamata, Chile

6 Mining and Environment Climate Process Type Type of ore deposit Mine-waste type Waste-dump Tailings impoundment Hydrology Ground water contamination Tailings deposit Sea Acid Mine Drainage (AMD)

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8 Concrete contains 2/3 sand. Sand is after Air and Water the 3rd mostly used resource Mrd t/a Average price for US industrial sand US$/ metric t Price range $8.40 $143.71(USGS, 2012) Construction sand has an average price in US of 7.8 (USGS, 2016)

9 March 2014 Home Subscribe Archive Contact Thematic focus: Ecosystem management, Environmental governance, Resource efficiency Sand, rarer than one thinks Sand and gravel are mined world-wide and account for the largest volume of solid material extracted globally. Formed by erosive processes over thousands of years (John, 2009), they are now being extracted at a rate far greater than their renewal. Furthermore, the volume being extracted is having a major impact on rivers, deltas and coastal and marine ecosystems (Figure 1), results in loss of land through river or coastal erosion, lowering of the water table and decreases in the amount of sediment supply. Despite the colossal quantities of sand and gravel being used, our increasing dependence on them and the significant impact that their extraction has on the environment, this issue has been mostly ignored by policy makers and remains largely unknown by the general public. Buh Snarf/Flickr/CC BY NC SA

10 Critical Elements Global Map

11 Size of mine tailings impoundments Total amount of tailings in Chile: Actual: wt.% Cu = 21.26Mt 6500 US/t = US$ Permits: t SERNAGEOMIN

12 Mineral composition of porphyry coppers Others Others Gypsum Weight Weight % in % Sample in Sample 100% 100% 90% 90% 80% 80% 70% 70% 60% 60% 50% 50% 40% 40% 30% %- 10% Ore minerals 90-99,9999% silicates Gypsum Apatite Apatite Rutile Rutile Ilmenite Ilmenite Alunite/Natroalunite Alunite/Natroalunite Cu-Pitch/WAD Cu-Pitch/WAD Other Cu-Sulphides Other Bornite Cu-Sulphides Bornite Chalcopyrite Chalcopyrite Covellite Covellite Chalcocite/Digenite Chalcocite/Digenite Brochantite Brochantite Chrysocolla Chrysocolla Other Cu-Oxides Other Fe Oxides/Hydroxides Cu-Oxides Fe Molybdenite Oxides/Hydroxides Molybdenite Pyrite 30% Pyrite Smectites 20% Smectites Kaolinite 20% 10% 10% 0% 0% Sample Sample Kaolinite Biotite/Phlogopite Biotite/Phlogopite Chlorite Chlorite Muscovite/Sericite Muscovite/Sericite K-Feldspar K-Feldspar Albite/Plagioclase Albite/Plagioclase Quartz Quartz

13 Economics of mine tailings %Cu with 12 km 2 surface t 6,500 US$/t = 6,05 Mrd US$ Mt 8 US$/t = 2,16 Mrd US$ Mt 100 US$/t = 8,10 Mrd US$ + Saved remediation costs: US$/ha = 0.6 Mrd US$???? + recovery of Social License (no waste production and pollution)...us$???

14 Basic Mathematics (-) x (-) = + minus plus minus equals positive Environmental Impact of Metal Mining - Destruction of ecosystems - Water contamination - Acid Rock Drainage (ARD) - Eolic transport Environmental Impact of Sand Mining - Free georesource - Destruction of ecosystems - Promotes beach erosion Additional Goody Critical Raw material extraction

15 Analytical Approach SOLIDS: Optical Microscopy X-ray diffraction (DXRD) Automated Quantitative Mineralogy (Mineralogic-Zeiss, ph QEMSCAN, - pe (Eh) MLA) - pk Laser-ICP-MS, Mircoprobe Synchrotron techniques like µ-xrd Stable Isotopes Sequential Extractions Organic matter & microbiology Dr. Bernhard WATER: Dold Centre d Analyse Minerale, Université de Lausanne, Switzerland Ion chromography, ICP-MS Stable Isotopes Organic compounds Bernhard.Dold@unil.ch

16 M-1908 Mineral Name Background Chalcopyrite Bornite Chalcocite Tennantite Pyrite Sphalerite Molybdenite Galena Other Sulphides Quartz K-Feldspar Plagioclase/Albite Epidote/Zoisite Tourmaline Amphiboles Sericite/Muscovite Biotite Kaolinite Montmorillonite Other Clays Chlorites Zircon Fe Oxides/Oxyhydroxides Rutile Ilmenite Titanite/sphene Calcite/Dolomite/Ankerite Siderite(Mn) Gypsum Other Sulphates Apatite Other

17 PRIMARY and SECONDARY RESOURCES PROCESS PRODUCT Historical Mine Waste Separation Sulfide concentrate-bioleach Complex oxide concentrate PLS As, Co, Cu, Ni, Fe, S Selective recovery of critical and toxic elements e.g. Co, Ni, W, Be, As, Fe 0, S 0. AMD Be, Bi, Co, Sn, W Cement & Ceramic Active Mining As, Be, Fe, S Activation: Lock-in of main contaminants In residual waste B e S Fe A s B e S A s Separation Activation: Lock-in of trace contaminants in final products Fe A s Fe Iron Oxides (e.g. magnetite containing Co) Sulfides (e.g. pyrite, pyrrhotite containing Co, Ni, As) Oxides ( scheelite (W), Helvin (Be)) Attraction of industry for manufacturing from silicate minerals e.g. SiO 2 solar panels, cement, ceramic,

18 Nucleus of Destruction Nucleus of sustainable Growth

19 Sustainable Mine Town Development Mining Architecture Cement Engineering

20 Future Mining in the Andes Comminution NO Mine-waste Only products Mineral Processing Type of ore deposit

21 Universidad Nacional San Augustin de Arequipa (UNSA), Peru Centro International de Investigación e Innovación Minera Sostenible (CI 3 MS) International Research and Innovation Center in Sustainable Mining (CI 3 MS) CI 3 MS

22 Universidad Nacional San Augustin de Arequipa (UNSA), Peru

23 Universidad Nacional San Augustin de Arequipa (UNSA), Peru

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25 Thank you! Muchas Gracias!