There will be a special bus from Warsaw (Pasteura 5, Faculty of Physics), to the conference site and back on Sunday 29 June. Approximate duration of travel 3 hours.
Warsaw Chopin Airport is located appr. 15 minutes by regular city bus (line 175 and 188) from Faculty of Physics, Pasteura 5 (bus stop "Banacha-Szpital").
The bus will leave Warsaw at 15:30 on 29 June.
The return bus will leave Chęciny on Saturday 5 July to reach Warsaw at. ca 13:00.
Alternative travel options via public transport: there is a regular train connection from Warsaw or Krakow to Kielce. In Kielce, you can take public bus no. 31 (timetable: [here]) and go to the penultimate stop in Chęciny (the stop is called "Chęciny / Małogoska" and is in Zone 2). From there you can reach the conference venue on foot (1.3 km, 15 mins.) or try finding a taxi.
The conference venue's address is:
Europejskie Centrum Edukacji Geologicznej Uniwersytetu Warszawskiego
Korzecko 1C, 26-060 Korzecko
[Google maps]