No, data mining can be used to find trends in data. I did TPS as an option, you probably haven't.
EG Through data mining of a retail store, it has found that beanies are often sold with scarves at the start of the footy season. This gives managers the opportunity to put these two types of items on sale, and effectively boost sales.
I can understand why you'd think it's a DSS, but I don't they can cross over? If they do, you just call it by what it's main function is.
It just seems silly to call every system that does data mining a DSS. I believe a question like that wouldn't be asked, anyway.