De or het miniconferentie?

The correct Dutch article is:

de miniconferentie

Rule Words ending in -tie and -sie: almost always de. See the rule

How to use miniconferentie

the miniconferentiede miniconferentie
this miniconferentiedeze miniconferentie
that miniconferentiedie miniconferentie
our miniconferentieonze miniconferentie
your miniconferentiejouw miniconferentie
every miniconferentieelke miniconferentie
which miniconferentie?welke miniconferentie?
a big miniconferentie / the big miniconferentieeen grote miniconferentie, de grote miniconferentie