Group of students or miners wandering round the space centre (7)
I believe the answer is:
seminar
'group of students' is the definition.
(I've seen this before)
'miners wandering round the space centre' is the wordplay.
'wandering' indicates an anagram.
'round' means one lot of letters goes inside another.
'centre' means to look at the middle letters.
The middle letter of 'space' is 'a'.
'miners' with letters rearranged gives 'seminr'.
'seminr' placed around 'a' is 'SEMINAR'.
'or' acts as a link.
(Other definitions for seminar that I've seen before include "Marines (anag.)" , "Study group on specific subject" , "Short intensive study course for marines" , "University course" , "Training meeting" .)