A small group of workers, under the leadership of a supervisor, seeking to make constructive...

Explanation

Quality circle.

Although it might be part of a quality initiative, the description describes a quality circle - a concept which has been credited with making significant improvements in some organisations, including, in some instances, creating cost savings. It is an important part of the idea of quality circles, that it is the actual workers, those at 'the coal face' (to use a somewhat outdated expression, perhaps) who lead and have the discussions. The belief, quite correct in my opinion, is the workers actually know what is going on, what is being done sensibly or otherwise, and therefore in operational terms, they need to be listened to.

A team at the working level, solving problems.