This is quite an abstract question, so I am not sure if this is really helpful to you:
You can do text mining with QV, but it's not a specialized tool to do such things. This means, you probably need to do a lot of stuff manually, if even possible with the function provided by QV.
You can for example make use of the QV string functions to match some patterns.
There are some examples here in the forum that were coping with unstructered text input data.
Though the QV functions are limited in providing text mining capabilities, there is also the possibility to use extensions or some 3rd party stuff, e.g. like references here:
or look into the semtiment analysis connector in QVSource.