Elgg might be useful for Volt or not. It impossible to say not knowing what exactly it's supposed to be used for. It a social network framework that can be customized for many different use cases and there are also plugins already available to provide additional functionality not yet included in the Elgg core package.

Maybe the technical people you mentioned could evaluate Elgg at least briefly - maybe with the desired requirements already in mind. If you still think that Elgg might be of use for Volt you might be able to ask some more specific questions how your requirements and Elgg's functionality fit together.