French term (edited): colloque ; colloque de fin de programme

For a scientific « colloque », then the INRA definition may be useful. It does indeed seem to tie in perfectly with Symposium. However, unless your event is overtly academic, I think the more familiar “Conference” would be fine. Plenty of hits on Google for “Mining Conference”.
As for the end of programme “colloque”, well, read oddly in French given how a common usage would make it the biggie, not the thing at the end. I would opt for something more along the lines of debate, session etc. I found “exchange session” here and quite like it.

http://mining12.mapyourshow.com/5_0/sessions/session_results...

Other references :

http://www.inra.fr/internet/Projets/colloque/vade-mecum/defi...

Un colloque scientifique se définit comme :

Une rencontre entre des participants
• de toutes origines professionnelles,
• du secteur public ou privé,
• français et étrangers,
• dont le but est la confrontation et la diffusion de résultats de travaux de recherches.
Cette réunion :
• se déroule sur plus d'une journée
• donne lieu à une organisation et une gestion globale.
Depuis 1995, la Direction de la Comptabilité Publique a permis une simplification des modalités de la gestion publique des colloques. Ceci à la condition expresse que :
la participation à un colloque donne lieu à paiement de droits d'inscription



http://fr.wikipedia.org/wiki/Colloque

À l'origine Colloques, du latin colloquium, désigne des conférences religieuses tenues dans le but de discuter un point de doctrine ou de concilier des opinions diverses. Par extension, il désigne des conférences de spécialistes (scientifiques).


http://fr.wiktionary.org/wiki/colloque

Conférence ou communication scientifique présentée dans un cadre académique.


http://en.wikipedia.org/wiki/Academic_conference

An academic conference or symposium is a conference for researchers (not always academics) to present and discuss their work. Together with academic or scientific journals, conferences provide an important channel for exchange of information between researchers.


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Note added at 11 hrs (2012-04-30 20:27:14 GMT)
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@ Michael :
Oo, that reads a little unpleasantly Michael, tongue in cheek at best.
The points? I don't give a hoot about them. And, on a slightly tongue-in-cheek tone by way of reply, the main purpose of my posting an answer is for "exchange session" which I found in a mining related document and which I thought might be helpful after having realised, late in the day, that the main point of the question relates to the use of "colloque" for the session at the end of the event. For the main event, yes, symposium, which if you read through my posts etc, you will appreciate I have made no secret about having changed my mind.

This is not the first time I find one of your comments "limite". I honestly don't know how to take them, but you do have a way with words, en effet !