Case study:

The Altenberg Tailing Dam in Germany

Dr. Ing. F.C. Benthaus, Dipl.-Ing Maike Kühn

Challenges and environmental solution in

degraded areas:

National and international experiences

FGV PROJETOS

Case Studies:

Altenberg Bielatal Tailing Compound

Rio de Janeiro

13.09.2017

Folie 2

Altenberg Mine

Remediation and securing Altenberg Tailing Dam

Berlin

Case Studies:

Altenberg Bielatal Tailing Compound

Rio de Janeiro

13.09.2017

Folie 3

Altenberg Bielatal Tailing Compound

Remediation Task:

Long term stability

Dewatering mine

Surveying Tailing Dam

- Tin Mining since 1440

- Industrial Mining since 1960

- Closed 1991

Case Studies:

Altenberg Bielatal Tailing Compound

Rio de Janeiro

13.09.2017

Folie 4

Operating time 1967 – 1991

Volumes ca. 10.5 Mio. m³

Surface 73000 m²

Dam height 80 m, Width: 680 m

Altenberg Bielatal Tailings Dam

Case Studies:

Altenberg Bielatal Tailing Compound

Rio de Janeiro

13.09.2017

Folie 5 5

Public Entities Mining Company Mining Authority

Participation of

Authorities

§ 54 BBergG a.o.

Nature

Agriculture

Water

Infrastructure

Work-out of a de-

commissioning plan § 53 BBergG Check of the prerequisites for

licensing by the mining authority § 55 BBergG

Consideration of the statements

Process for applying mining approval

Work-out of a draft licensing with

auxiliary conditions § 8 VwVfG

Licensing by mining authority § 55

BBergG

Statement of the

company

Presentation to public

entities Municipalities

Begin of Work

Case Studies:

Altenberg Bielatal Tailing Compound

Rio de Janeiro

13.09.2017

Folie 6

Approval Process for Tailings Compound Altenberg

1967 Approval for erecting the tailing pond

…

…

…

1975 Approval for enlargement

the tailing pond

…

…

…

…

…

1993 Approval for remediation of the tailing pond

…

…

1995 Risk assessment study

…

…

2011 Approval for long-term stability and flood prevention

Case Studies:

Altenberg Bielatal Tailing Compound

Rio de Janeiro

13.09.2017

Folie 7

Altenberg Tailings Dam Construction

Seepage line

Dam Construction

Sand Silt

Case Studies:

Altenberg Bielatal Tailing Compound

Rio de Janeiro

13.09.2017

Folie 8

Flood prevention by overflow canal

Flood prevention on a 1.000 year high water:

• Spillway chute for overflow

• Covering the thixotropic substance on surface

• Water cleaning plant

Case Studies:

Altenberg Bielatal Tailing Compound

Rio de Janeiro

13.09.2017

Folie 9

Passive Treatment Plant to reduce Iron and Arsenic Loads

Problem:

Seepage water 30l/s with As 1 mg/l

Solution:

Passive treatment plant:

Oxidation As(III) to As(V), Sorption on Fe OH

Fe-As Coagulation

Reduction up to 70%

Case Studies:

Altenberg Bielatal Tailing Compound

Rio de Janeiro

13.09.2017

Folie 10

Surveying and Monitoring Ground- and Surface Water Regime

Folie 10

Groundwater Surface Water Lake water

Reporte to the Autorithities

Mining - Water - Enviroment

Waterlevel Waterquality

Proof of the Piezometer Measuring Points, once a Month/Year

In Mining induceed Areas

Case Studies:

Altenberg Bielatal Tailing Compound

Rio de Janeiro

13.09.2017

Folie 11

Long Term Surveying Altenberg Tailings Compound

Results of 2015 monitoring

Dam movement: (once a year)

- 30 extensometer point

- 160 – 330 mm/a stable

Seepage line: (4 times a year)

- 12 piexometer

- Line of saturation: stable

Water Quality: (12 times a year)

- Dam outflow (Fe, As,…)

- Biela creek inflow (Fe, As,)

Report once a year to Mining Authority

Continuous monitoring: no risk at any time!

Case Studies:

Altenberg Bielatal Tailing Compound

Rio de Janeiro

13.09.2017

Folie 12

Iron in the River Spree

Ecological consequences:

water plants - lack of light

mussels – smother by fine silt

fishes – mud accumulation

(spawning grounds)

2

4

2

22 2 SOFeOFeS

Extensive Pyrite Weathering

of Groundwater

Case Studies:

Altenberg Bielatal Tailing Compound

Rio de Janeiro

13.09.2017

Folie 13

Master Plan Spree-River

From

Bärwalde (Saxonia)

…

… Via

Spreewald

(Brandenburg)

To Berlin

Worked out

by LMBV

Approved by

Mining and

Water Authorities

Case Studies:

Altenberg Bielatal Tailing Compound

Rio de Janeiro

13.09.2017

Folie 14

Iron Trap at Spremberg reservoir

Liming and Sedimentation

in the upper Pond of Spremberg Reservoir

m/s

Case Studies:

Altenberg Bielatal Tailing Compound

Rio de Janeiro

13.09.2017

Folie 15

Sedimentation Pond Project at Kahndorfer Lake

Case Studies:

Altenberg Bielatal Tailing Compound

Rio de Janeiro

13.09.2017

Folie 16

Social Disputes

Investigation upon depositing

iron bog in post mining lakes

Published by LMBV via internet

Water treatment plant Vetschau

Protesters at town hall and parliament

Case Studies:

Altenberg Bielatal Tailing Compound

Rio de Janeiro

13.09.2017

Folie 17

In-Situ treatment

at the inflow to the Spree river

In-Situ aquifer treatment through microbial iron reduction

FIB: Mikrobiell induzierte Eisenretention zu Fließgew ässern:

Pilotprojekt Ruhlmühle 2014

Reduction Result:

-Iron: 70 - 90%

-Sulfate: 80 - 95%

-pH Value +30%

Case Studies:

Altenberg Bielatal Tailing Compound

Rio de Janeiro

13.09.2017

Folie 18

Long-term Safeguarding the Altenberg Tailing Compound

Case Studies:

Altenberg Bielatal Tailing Compound

Rio de Janeiro

13.09.2017

Folie 19

Summary

Tailings are an inherent risk:

Tailing management could reduce the risk

Long-term Surveying necessary

Organizational and technical Solutions

available for River basin management

GLÜCKAUF OBRIDADO fc.benthaus@lmbv.de