In addition to these core domains I have maybe 10 domains which are rich in keywordsfor the area of business.
I'm hoping you might all have some suggestions on utilising these domains to build traffic and improve the ranking for the company name website.
What is the worst that could happen if one of your mini sites outranks your main site? Having 2 of your sites on the front page of the SERPS is better than having 1 of your sites and 1 more of a competitor's site.
In my case, I have widgetworks and rank well for "widget software". I am working on a mini site for "gadget software" and putting it on gadgetsoftware.com. I never have ranked at all for the gadget keyword while that is my competitor's leading keyword. I figure I can rank high for my primary keyword and this mini site can rank high for my competitor's primary keyword.
Good luck