How would you define data mining? Is it "running complex algorithms on large amounts of data to detect any patterns", or is it "efficiently and quickly exploring large amounts of data visually to see if there is anything interesting"?
Tableau is a great tool to data visualization or data presentation.
As I understand data mining, if you want deeper analysis than a linear regression will have to use some different software adapted to data mining.
I personally use other tools (SAS, SPSS, RapidMiner, R, XLSTAT...) for clustering, factor analysis, regression models more complex that a simple reg... and when I get a relevant results (ie. customer segmentation) I will apply it at the database level. Later I use Tableau just to read these results and show on dashboards.
At the end of any software does it all, you have to adapt working methods to problems arising in the organization
I used SPSS, R et XLSTAT. I advice you weka.