- Uppsala (Sweden), 2nd International Symposium on Environmental Geochemistry, 1991
- Ljubljana/Pörtschach (Slovenia/Austria), 4th International Mine Water Association Congress, 1991
- Canberra (Australia), International Volcanological Congress, 1993
- München (Germany), Hanns-Seidel-Stiftung, 1993
- Kraków (Poland), 3rd International Symposium on Environmental Geochemistry, 1994
- Nottingham (United Kingdom), 5th International Mine Water Association Congress, 1994
- Perth (Australia), 12th Australian Geological Convention, 1994
- Perth (Australia), CSIRO, 1994: Flooding of an abandoned Uranium Mine in the Erzgebirge/Saxonia/ Germany
- München (Germany), Hanns-Seidel-Stiftung, 1994: Trinkwasservorkommen und deren Gewinnung
- Melbourne (Australia), Monash-University, 1995: Changes in Mine Water Geohydrology during the Flooding of an abandoned Uranium Mine in the Erzgebirge/Saxonia/Germany
- Freiberg (Germany), Uranium-Mining and Hydrogeology, 1995
- Miskolc (Hungary), Miskolci Egyetem, 1995: Flooding of a Uranium Mine – Environmental Problems and Geochemical Conditions
- Bautzen (Budyšin, Gemany), IFG, 1997: Neue Wege für Niederschlagswasser – Hydrogeologische Untersuchungen zur Regenwasserversickerung in Ostsachsen
- Portorož (Slovenia), 7th International Symposium on Water Tracing, 1997
- Bled (Slovenia), 6th International Mine Water Association Congress, 1997
- Johannesburg (South Africa), International Mine Water Association Symposium, 1998
- Freiberg (Germany), Uranium-Mining and Hydrogeology II, 1998
- Sevilla (Spain), International Mine Water Association Congress, 1999
- Ustroń (Poland), 7th International Mine Water Association Congress, 2000
- München (Germany), XXXI. IAH Congress, 2001
- Belo Horizonte (Brasil), International Mine Water Association Symposium; Brazilian Mining Conference 2001
- Nottingham (United Kingdom), Mine Water Hydrogeology and Geochemistry, 2001
- Kattowitz (Poland), 2nd Image-Train cluster meeting, 2002
- Lake Orta (Italy), Mine and quarry waste – The burden from the past, 2002
- Lausanne (Switzerland), M-WINE initial meeting, 2002
- Freiberg (Germany), Uranium-Mining and Hydrogeology III; International Mine Water Association Symposium, 2002
- Johannesburg (South Africa), 8th International Mine Water Association Congress, 2003
- Freiberg (Germany), 3. Altbergbaukolloquium, 2003
- Cairns (Australia), James Cook University, 2004: Tracer Tests in Flooded Underground Mines
- Jena (Germany), Friedrich-Schiller-Universität, 2004: Troia – Hydrogeologische Untersuchungen im Historischen Nationalpark
- Freiberg (Germany), 55. Berg- und Hüttenmännischer Tag, 2004
- Newcastle (United Kingdom), International Mine Water Association Congress, 2004
- Oviedo (Spain), 9th International Mine Water Association Congress, 2005
- Freiberg (Germany), 56. Berg- und Hüttenmännischer Tag, 2005
- St Louis (USA), International Mine Water Association Symposium, 2006
- Berlin (Germany), IAH Meeting, 2006
- Cagliari/Sardinia (Italy), International Mine Water Association Symposium, 2007
- Freiberg (Germany), 58. Berg- und Hüttenmännischer Tag, 2007
- Carlsbad (Czech Republic), 10th International Mine Water Association Congress, 2008
- Freiberg (Germany), 59. Berg- und Hüttenmännischer Tag, 2008
- Pretoria (South Africa), International Mine Water Association Symposium, 2009
- Freiberg (Germany), 61. Berg- und Hüttenmännischer Tag, 2010
- Sydney, Nova Scotia (Canada), International Mine Water Association Symposium, 2010
- Beijing (China), 17th Global Energy & Resources Dialogue: 2011 World Underground Mining Conference, 2011
- Xuzhou (China), China University of Mining and Technology: Mine Water Management and Tracer Tests, 2011
- Gera (Germany), WISSYM – Remediation of Uranium Mining and Processing Sites – Sustainability and Long Term Aspects, 2011
- Aachen (Germany), International Mine Water Association Congress, 2011
- Atlanta (USA), Kemira Oy – Mine Water Short Course, 2011
- Johannesburg (South Africa), Water Management in Mining Africa, 2011
- Bunbury (Australia), International Mine Water Association Symposium, 2012
- Pretoria (South Africa), Water Management in Mining Africa, 2012
- Mikkeli (Finland), Mine Water Management Lecture, 2013
- Golden (USA), International Mine Water Association Conference, 2013
- Helsinki (Finland), Green Mining Seminar, 2014
- Santiago (Chile), International Mine Water Association & ICARD 2015
- Helsinki (Finland), WaterSmart Status Seminar, 2015
- Bad Schlema (Germany), WISSYM 2015
- Pretoria (South Africa), CGS Congress 2016
- Helsinki (Finland), Green Mining Congress 2016
- Leipzig (Germany), International Mine Water Association 2016
- Lappeenranta (Finland), Nordic Filtration Symposium 2016
- Lappeenranta (Finland), International Mine Water Association 2017
- Wuhan (China), 2nd National Chinese International Mine Water Association Meeting 2017
- Saariselkä (Finland), Kaivosseminaari 2018
- Vienna (Austria), IAEA Technical Committee Mine Water Management, 2018
- Pretoria (South Africa), 11. ICARD / IMWA Conference, 2018
- Umhausen (Austria), Geoforum Umhausen, 2018
- Wielicka (Poland), 18. Altbergbau-Kolloquium, 2018
- Freiberg/Sachsen (Germany), VODAMIN II Workshop Mine Water Geothermal, 2019
- STOP THE WAR AGAINST THE UKRAINE! Perm (Russia), International Mine Water Association Conference – Mine Water: Technological and Ecological Challenges, 2019
- Bochum (Germany), Bergbau, Energie und Rohstoffe, 2019
- Chemnitz (Germany), WISSYM19, 2019
- Umhausen (Austria), Geoforum Umhausen, 2019
- Virtual Conference (Wales, United Kingdom), 14th International Mine Water Association Congress – Mine Water Management for future Generations, 2021
- Breslau / Wrocław (Poland), Politechnika Wrocławska, 2022
- Kassel (Germany), kassel22 – Let’s talk about Grubenwasser, 2022
- Johannesburg (South Africa), WISA Biannual Conference, 2022
- Christchurch (New Zealand), 14th IMWA Congress, 2022
- Newport, Wales, IMWA 2023
- Kassel (Germany), kassel23 – Let’s talk about Grubenwasser, 2023
- Essen (Germany), 21. Altbergbau-Kolloquium, 2023
- Johannesburg (South Africa), WISA Mine Water Symposium, 2023
: Invited or Keynote Speaker