Mining residues: legacy or chance? · 2do Foro Peruano-Alemán de Minería y Recursos Minerales...

2do Foro Peruano-Alemán de Minería y Recursos Minerales“Extracción de Materias Primas y Desarrollo Sustentable”

Bergbauabfälle: (Alt-)Last oder Chance?

Mining residues: legacy or chance?

Dr.-Ing. Sven-Uwe Schulz

Deutsche Rohstoffagentur (DERA) in der

Bundesanstalt für Geowissenschaften und Rohstoffe (BGR)


Federal Institute for Geosciences and Natural

Resources (BGR):

central geoscientific authority providing

advice to the German Federal Government in

all geo-relevant questions

subordinate to the Federal Ministry for

Economic Affairs and Energy (BMWi)


Raw Materials Information

and Analyses

Contribution for Securing Raw Materials

Supply

1.

Raw Materials Information System

2.

Risk Assessment

3.

Raw Materials Potentials

4.

Diversifying Supply

Development of Strategies for Security of Supply, Network Building, Raw Material Dialogues, Industry Workshops, Conferences

Organization of the German Raw Materials Efficiency Award

Se

rvic

es

Improving market transparency in the mineral resources sector by

providing minerals information and analysis and advise companies

about price and supply risks

Sustainable and Secure Supply of Mineral Resources for Germany

Ta

rge

ts Professional backing of measures taken by

the German government and companies

to secure raw materials supply

Mineral Economics Evaluation of Mineral Resources

German Mineral Resources Agency (DERA): Mission


The German Government‘s raw materials strategy

improvement of access to raw materials for the

German industry

helping German industry to diversify its sources of

raw materials

establishing bilateral raw material partnerships with

selected countries

developing technologies and instruments to improve

the conditions for recycling and substitution

helping industry to develop synergies through

sustainable economic activity and enhanced

materials efficiency

creating transparency and good governance in raw

materials extraction

integrating national measures with European policy

on raw materials


Common residue types during material use (direct)

source: after Rankin, W. J. (2011)

leach residues,

el.-refining residues,

slag, fume, furnace

refractories

(from furnaces)

solids

liquids

gases

Acid Rock Drainage

(from tailings)

tailings

CO2

(from fuel combustion)

Acid Mine Drainage

(from mines & heaps)

waste rock,

dust

acid/alkaline solutions

from leach residues,

cyanide containing

solutions (Au)

CO2, SO2, NOx, etc.

(from smelting)

In-plant scrap,

dross,

mill scale

pickling liquids, electro-

plating liquids

CO2

(from furnaces)

el. arc furnace dusts,

dross from Al-recycling

Waste process solutions

containing metals

CO2, NOx etc.

(from furnaces)

numerous types of waste during

recycling of scrap metals, electronic

scrap, consumer goods etc.

MiningProcessing

(Benefciation)

Chemical

Transformation

Fabrication &

manufactureRecycling

(Beneficiation)


Common residue types during material use (indirect)


leach residues,

el.-refining residues,

slag, fume, furnace

refractories

(from furnaces)

solids

liquids

gases

Acid Rock Drainage

(from tailings)

tailings

CO2

(from fuel combustion)

Acid Mine Drainage

(from mines & heaps)

waste rock,

dust

acid/alkaline solutions

from leach residues,

cyanide containing

solutions (Au)

CO2, SO2, NOx, etc.

(from smelting)

In-plant scrap,

dross,

mill scale

pickling liquids, electro-

plating liquids

CO2

(from furnaces)

el. arc furnace dusts,

dross from Al-recycling

Waste process solutions

containing metals

CO2, NOx etc.

(from furnaces)

numerous types of waste during

recycling of scrap metals, electronic

scrap, consumer goods etc.

MiningProcessing

(Benefciation)

Chemical

Transformation

Fabrication &

manufactureRecycling

chemical wastes from explosives manufacture or

from reagent manufacture

fly ash from electrical power generation

CO2 from several process steps:

mainly electrical power generation, explosives manufacture

(Beneficiation)


Accumulation of (solid) waste materials through the mining process

Darstellung NICHT maßstäblich / image NOT in scale

Metall

Metal

Schlacke(n)

Slag(s)Konzentrat(e)

Concentrate(s)

Bergbau

Mining

Aufbereitung

(Ore) Processing

Grubenwasser

Mine water

Abraum

Overburden

Abgänge

Tailings

Abwasser

Waste water

Berge

Waste rock (gangue)

Hütte

Smelter

Lagerstätte

Deposit

Roh(erz)förderung

Run-off-mine (ROM) ore

Vorräte

Inventory

Abraum-/Berge-Halden

Waste rock dumps

Aufbereitungshalden / Schlammteiche

Tailings dams & ponds

Schlackehalden

Slag dumps


Composition of typical solid wastes during copper production (wt%)

sourc

e: aft

er

Rankin

, W

. J. (2

011)

0,1

% -

0,4

%

3%

-7

%

1%

-4

0%

11

%

1%

-2

%

3%

-5

%

28

% -

35

%

0,0

3%

-2

%

0,1

% -

74

%0

,3%

-1

1%

1%

-1

,5%

0,5

% -

4,5

%

0,3

% -

8,5

%

0,3

% -

0,7

%

37

% -

44

%

28

% -

33

%

0,5

% -

27

%

4%

-2

9%

7%

-1

2%

1%

-1

3%

0,3

% -

45

%

0,6

% -

1,6

%

1,5

% -

12

%

0,0

2%

-0

,4%

0,0

4%

-2

%

0,2

% -

0,8

%

0

10

20

30

40

50

60

70

80

Cu

Fe S

Al2

O3

Mg

O

Ca

O

SiO

2

As

Pb

Mo

Zn

Sb Bi

Cd

Cu

Fe S

Al2

O3

Mg

O

Ca

O

SiO

2

As

Pb

Mo

Zn

Sb Bi

Cd

Cu

Fe S

Al2

O3

Mg

O

Ca

O

SiO

2

As

Pb

Mo

Zn

Sb Bi

Cd

Cu

Fe S

Al2

O3

Mg

O

Ca

O

SiO

2

As

Pb

Mo

Zn

Sb Bi

Cd

waste rock Flotation Tailings Final slag (discarded) smelter dust and fumes

waste rock flotation tailings final slag

(discarded)smelter dust & fumes


Quantities (indicative) of solid wastes during production of 1 ton Au, Cu, Al


Gold Copper

(heap leaching)Aluminium

ore grade 2 ppm Au 1 wt% Cu 35 wt% Al

waste rock : ore ratio 0,5 3 1

recovery

mining 90% 90% 90%

processing 100% 95% 90%

leaching 85% 85% 90%

electro-winning 100% 99% 100%

Total (overall recovery) 77% 72% 73%

rock waste and ore left unmined 390.000 429 4,31

tailings (dry basis) - 25,9 0,75

leaching residues 590.000 97,5 0,89

electro-winning residues - 0,1 -

total (tons waste per tonne product) 980.000 553 5,95


Annual amount of mining related wastes in Germany

48,2 49,2 45,5 46,7 50,5 52,3 42,0 42,9 39,3 27,5 36,9 34,7 30,3 29,3 30,2

358,5

34

6,0

33

5,8

319,7

28

8,9

27

9,6

298,9

30

8,2

30

5,3

294,8

29

5,8

30

8,1

30

3,3

30

9,4

32

0,1

0

50

100

150

200

250

300

350

400

450

2000 2001 2002 2003 2004 2005 2006 2007 2008 2009 2010 2011 2012 2013 2014

an

nu

al

am

ou

nt

of

waste

in

mn

to

nn

es

mining related wastes other wastes*

sourc

e: S

tat. B

undesam

t(2

016)

* exkluding wastes from waste treatment plants


Mining and smelter related residues in Germany

source: r³ joint project REStrateGIS (2015)

resource cadaster for stockpiles (mine waste and smelters) for Germany

joint project of several scientific institutions funded by Ministry of Education and Science

additional analytics and modelling for estimation of inventory


Mining and smelter related residues in Germany and their mineral potential

source: r³ joint project REStrateGIS (2015)

more than 1,000 stockpiles in Germany

app. 250 included

app. 250 mn tons of material considered

element

theoretical potential technical potential

min. (mn t) max. (mn t) min. (mn t) max. (mn t)

iron 4.11 44.86 0.62 6.,73

non-ferrous metals 0.46 22.70 0.07 3.40

steel alloys 0.35 8.14 0.05 1.22

critical raw materials 0 0.18 0 0.03


Legal framework in Germany

Federal Mining Law (BBergG)

Environmental Laws (forests, water ...)

Life-Cycle management act (KrWG)

...

prevention

preparing for re-use

recycling

recovery

disposal


Handling and management of mining residues - good practise

http://www.fch.cl/wp-content/uploads/2016/08/Buenas-Practicas-en-la-Gestion-de-la-Estabilidad-Quimica-en-la-Industria-Minera.pdf


Handling and management of mining residues - good practise

http://www.fch.cl/wp-content/uploads/2016/08/Buenas-Practicas-en-la-Gestion-de-la-Estabilidad-Quimica-en-la-Industria-Minera.pdf

1


Rehabilitation of the former uranium open pit mine Lichtenberg

Build up of a landscape construction

mining operation between 1958 & 1976

final open pit depth 230 m

cumulative production app. 15 mn tons uranium ore,

resp. 12.670 tons uranium metal

rehabilitated area 2015ultimate pit Lichtenberg 1991


Rehabilitation of the former uranium open pit mine Lichtenberg

backfill with stockpile material classified by acid mine drainage potential A (high) to C (low)

minimization of radiologic and chemical influence on air and waters (underground and surface)

zone C

zone B

zone A

backfill model

open pit Lichtenberg

stockpile block model

Backfill concept


Chances and potentials of mining residues

“There are some miners who wash over the

dumps from exhausted and abandoned mines,

[…]; and others who smelt the old slags; from all

of which they make an ample return.“

„Etliche Bergleute beschäftigen sich auch damit,

die Halden, die einst aus den Gruben gefördert

und damals gering geschätzt wurden, […] zu

waschen; andere schmelzen alte Schlacken.

Sie ziehen daraus nicht selten sogar einen recht

reichen Gewinn.“

Georgius Agricola (1556): De Re Metallica Libri XII


Motivation for (re-)evaluation of the potential of mining dumps and tailings

high prices

increased demand for previously not processed byproducts

new/improved processing technology

environmental aspects

safety/stability


Examples of BGR/DERA work in the field of potentials assessment

Chromite & PGE potentials in tailings of the Bushveld complex, South Africa

evaluation of copper tailings in Chile

interdisciplinary 3D investigations on tailings impoundments

bioleaching of metal sulfides in mine waste

regional cooperation for sustainable mining



PGE: operation

tailings

Chrome: operation

tailings

tailings

average grade material

[mn t]

PGE

[Moz]

Cr2O3

[mn t]PGE

[ppm]

Cr2O3

[%]

PGE operations 0.65 5 – 10 2,089 39 172

Chromite operations 2.25 20 43.5 2.8 8.7

total 2,132.5 41.8 180.7source: DERA 2015



source: DERA 2015

Mooinooi, tailings

Millsell, tailings

Impala, tailings

Tailings from chromite mining Tailings from PGE mining

Impala, tailings



source: DERA 2015

Western limb 81%

Eastern llmb 10%

Northern limb 9%

171.83 Mt Cr2O3

Chromite and PGE potential in tailings

from PGE mining:

Western limb 83%

Eastern limb 10%

Northern limb 7%

38.8 Moz PGE

Chromite and PGE potential in tailings

from chromite mining:

Western limb50%

Eastern limb44%

North.limb6%

8.64 Mt Cr2O3

Western limb50%Eastern

limb43%

Northern limb7%

2.8 Moz PGE


Evaluation of copper tailings in Chile

definition of selection criteria

(Tonnage, age of tailings, metal content,

ownership, legal questions)

pre-screening of the available information,

sampling of selected tailings selection of 1 – 2

demonstration projects

in-depth analysis of selected demonstration

projects

(chemical and mineralogical analyses, drilling,

bio-leaching tests)

economic evaluation and environmental impact of

potential reprocessing & rehabilitation

continuous exchange of information with

companies, potential investors, government


Evaluation of copper tailings in Chile (part 1 in 2014-2015)

12 mine sites visited

81 samples analyzed for main and trace elements

copper grades between 0.1 % and 3.7 %

in some special layers

further elements of economic interest are among

others:

Fe, Au, Mo, Zn …

selection of 4 sites for deeper investigation

4 samples each 20 – 30 kg tailings material, were

taken from:

Minera Clarita (Cu-Au, 5 mn t),

Taltal (Cu, 2 mn t, Enami),

El Salado (Cu-Au, 1 mn. t Enami),

Minera Carola (Cu, 30 mn t)


Evaluation of copper tailings in Chile (part 1 in 2014-2015)

results:

to be continued in 2016 - ...

dump no. tailings Cu conc. recoveryCu content

(real)

value

@ 4.500 US$/t

value

@ 5.500 US$/t

1 1 mn t 0.40% 60% 2,400 t $10,800,000 $13,200,000

2 2 mn t 0.45% 70% 6,300 t $28,350,000 $34,650,000

3 2 mn t 0.47% 84% 7,896 t $35,532,000 $43,428,000

4 5 mn t 0.12% 50% 3,000 t $13,500,000 $16,500,000

5 5 mn t 0.11% 66% 3,630 t $16,335,000 $19,965,000


Interdisciplinary 3D investigations on tailings impoundments

Recoverability of raw materials from complex tailings

Complexity of internal tailings structure:

depositional fractionation of minerals by grain size, density or shape

partial weathering affecting minerals, minerals surfaces and texture

changes of source material or mineral treatment techniques

Target exploration requires suitable methods to understand :

internal structure due to deposition and alteration

enrichment/depletion processes

mineral surface conditions and mineral assemblages

Methods to achieve goals:

2D mineralogical and chemical investigations

2D hyperspectral imaging

tomographic geophysical investigations

3D CPT-EDXRF measurements

Sampling at Los Ninos tailings (Cu) in Copiapó (CHL)

EDXRF M4-Tornado element distribution showing

texture and a Cu-enriched zone; from Los Ninos


Bioleaching of metal sulfides in mining wastes

Biomining (applied geobiotechnology of bioleaching):

extraction & recovering of valuable metals from sulfidic ore deposits

app. 15 % of world copper production from bioheapleaching

mainly in Chile

more than 40 years experience in R&D on bioleaching of metals from different ores and residues at BGR

e.g. > 100 scientific publications on copper shale, mine tailings, ashes

BGR R&D results:

mining residue dumps and tailings e.g. in Chile and Peru with significant amounts of valuable metals, extractable via bioleaching

Mine waste tailings at Ticapampa in PeruBioreactor in BGR lab


program of the German

Federal Ministry for Economical

Cooperation and Development in the

Andean countries:

Bolivia

Chile

Colombia

run by GIZ and BGR

main goals:

economic sustainability

design and implementation of policies, strategies and incentives for sustainable use of mineral

raw materials

ecologic sustainability

support for the adoption of modern environmental technologies (water/energy management,

renewable energies, treatment and management of mining residues (PAM)

social sustainability

development of a structured cooperation between all stakeholders in the mining context

(dialogues, negotiations, practices and instruments of mediation)

Regional cooperation for sustainable mining –

Example: Pataz, La Libertad, Perú

Ecuador

Peru

Photo: L. Winkelmann, BGR


“Se precisa una forma de pensar

completamente nueva para resolver los

problemas que hemos creado con

nuestra vieja manera de pensar.”

¡Muchas gracias! Thank you very much! Vielen Dank!

“The world we have created today has

problems which cannot be solved by

thinking the way we thought when we

created them.”

„Probleme kann man niemals mit

derselben Denkweise lösen, durch die sie

entstanden sind.“

Albert Einstein

Mining residues: legacy or chance? · 2do Foro Peruano-Alemán de Minería y Recursos Minerales...

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