Role of mining industries in implementation of innovative strategies in metal recovery

Transcription

1 ERAMIN 2015 Sustainable Supply of Raw Materials in Europe Role of mining industries in implementation of innovative strategies in metal recovery Jorge M. F. Carvalho BioCriticalMetals Kickoff meeting Coimbra, 6 th - 7 th June

2 EDM Empresa de Desenvolvimento Mineiro, SA. EDM is a Portuguese State owned company, which operates in the areas of Environment and Mineral Resources: In an exclusive basis, with license granted by the Portuguese Government, develops and conducts the environmental remediation and monitoring of 175 abandoned mining sites, By itself or in Joint-Ventures, develops exploration activities of mineral deposits in world class metallogenic provinces of Portugal aimed at maximizing its mineral resources potential for exploitation 2

3 Old Mining Legacy Mining is a very old activity in Portugal During Roman times (from I B.C. to IV A.C.), the territory was extensively explored and exploited for gold; : main period of mining activity in Portugal; Small mines of tungsten, tin, uranium, pyrite, copper, lead, gold and silver; Environmental damage arising from the exploitation and essentially from the abandon of mining activities 3

4 The Inventory of old abandoned mines MINERAL TYPE GROUPS NUMBER OF MINES MOST RELEVANT OLD MINES Radioactive minerals 61 Urgeiriça, Quinta do Bispo, Cunha Baixa e Bica Polimetallic Sulphides 10 São Domingos, Aljustrel, Lousal e Caveira Tin and Tungsten 40 Argozelo, Covas, Montesinho e Terramonte Base Metals 28 Terramonte, Coval da Mó e Miguel Vacas Iron and Manganese 16 Orada, Cercal / Rosalgar e Ferragudo Coal 3 São Pedro da Cova e Pejão Gold 12 Jales, Penedono e Freixeda Others 4 Gouveia de Baixo e Cortes Pereira Asbestos 1 Arado do Castanheiro TOTAL 175 4

5 The main environmental problems Heaps, tailings and other mining residues 5

6 The main environmental problems Acid mine drainage 6

7 The main environmental problems Open pits and security issues 7

8 OLD MINING RESIDUES 8

9 OLD MINING RESIDUES Most of the old abandoned sites have piles of mining residues Two main types Coarse granular residues of sterile waste rock, low grade ores and slags; Very fine-grained residues from the beneficiation and processing of the high grade ores. Normally disposed in type-specific waste piles. 9

10 São Domingos - Achada do Gamo Dispersed piles of slags and tailings 10

11 Jales old gold mining tailings 11

12 Mining Residues - The Environmental Problem Volume & Stability conditions Components Nature (chemical, mineralogical, grain size) Dust dispersion Leaching/Acid water drainage Geotechnical hazards Radioactivity Streams, soils and aquifers contamination 12

13 ENVIRONMENTAL REMEDITATION Adopted Solutions Transition 20 th - 21 st centuries Mainstream policy 13

14 ENVIRONMENTAL REMEDITATION Adopted Solutions General characterization Prioritization of old mining sites intervention General planned and adopted solutions for waste piles: Confinement and Waterproof sealing (total or partial) 14

15 SOME EXAMPLES URGEIRIÇA (uranium & radium ores) Barragem Velha tailings 15

16 COVAS TUNGSTEN MINE 16

17 ARGOZELO TIN & TUNGSTEN MINE 17

18 JALES GOLD MINE 18

19 NEW VISION NEW PARADIGMA? MINING WASTES AS SECONDARY SOURCES OF MINERAL RAW MATERIALS 19

20 FRAMEWORK FOR THE REUSE OF OLD MINING RESIDUES More efficient use of resources, although lagged temporally. Minimizing environmental problems by removing the contaminants. Use of the residues framed within the Environmental Recovery of Degraded Areas Mining 20

21 WASTE RAW MATERIAL SOURCE Big questions Available volume? Which minerals? Available grades? Optimistic starting point since there was a significant improvement in the ore exploitation and processing methods. Need for detailed characterization (volume, internal structure, particle size, petrography, mineralogy, chemistry,, microbiological content, ). 21

22 WASTE RAW MATERIAL SOURCE More questions Which type of environmental remediation was applied? Confinement? Sealing? No intervention? Which efficient exploitation method to be applied without jeopardizing the environmental interventions already done? 22

23 WASTE RAW MATERIAL SOURCE And the economic factor: Poor economic performance: at least contribution to minimizing the environmental hazards Good economic performance: contribution to the decrease or full coverage of the maintenance and monitoring costs 23

24 A first preliminary selection of the most relevant Portuguese old mining wastes as possible secondary sources of mineral raw materials 24

25 Exploited minerals CRITERIA Gold (Au) (Standard economic safe asset, high-tech electronics, jewelry) Tungsten (W) (Hard-metal alloys, magnets, Critical Raw Material) Antimony (Sb) (Pb-based alloys in batteries, flame retardant, CRM) Base Metals (Cu, Pb, Zn) (Exploited from sulphide minerals that are the major cause for acid water drainage but may contain high-value elements (Au, CRM, REE) Radioactive ores were not considered (specific environmental and legal issues) Volume of waste piles > 50x10 3 m 3 25

26 RESULTS Mining Site Primary Raw Material Waste Type Confined waste Volume of wastes ('000 m 3 ) Jales Au Tailings X > 250 Penedono Au Waste rock and Tailings Aljustrel- Algares Cu, Pb, Zn Waste rock and Tailings > 250 São Domingos Cu, Pb, Zn Waste rock; Tailings, slags > 250 Caveira Cu, Pb, Zn Waste rock Aparis Cu Waste rock Miguel Vacas Cu Waste rock Mostardeira Cu Waste rock Talhadas Cu, Pb, Ag Waste rock Tinoca Cu Waste rock X Terramonte Pb, Zn, Ag Tailings X Braçal Pb Waste rock and Tailings Argozelo Sn, W Waste rockand Tailings X Montesinho Sn (w) Waste rock Bejanca Sn, W Waste rock and Tailings Góis Sn, W Waste rock Ribeira Sn, W Waste rock Murçós Sn, W Waste rockand Tailings X Borralha W Waste rock and Tailings Covas W Waste rock and Tailings X Fonte Santa W Waste rock X

27 NEXT STEPS To find the correct partners Portuguese Partnership for Mineral Resources North, Central and Alentejo regions of Portugal To build an action and work plan To build a funding schema P2020 (POSEUR / COMPETE2020) H

28 PRELIMINARY ACTION PLAN YEAR 1 YEAR 2 YEAR 3 YEAR 4 CARACTERIZATION R&D METHODOLOGIES PILOT TESTS PRODUCTION EDM SPIN-OFF EDM joint venture 28

29 FINAL CONSIDERATIONS The research activity in Portugal concerning old mining residues is still very focused on looking for sensors and consequences of pollution. It should evolve to innovative engineering solutions that contribute to the reduction of environmental issues by capturing, concentrating and collecting the existing pollutants in the mining residues. 29

30 FINAL CONSIDERATIONS So, a paradigm shift is needed to allow these wastes to be considered as secondary sources of mineral raw materials. First step: Demonstration that they can be reused. Has to be based on a suitable characterization of the existing mining wastes. The action plan must be legally framed by the Environmental Recovery Concession. 30

31 R. Sampaio e Pina, nº 1 3 Dtº LISBOA Geral Tel: (+351) Fax (+351) edm.mineira@edm.pt Jorge M. F. Carvalho jorge.carvalho@edm.pt 31