This is the easiest way to get setup:
Download and install the debugging tools for windows - I prefer c:\debuggers but you can install it wherever you like.
Then open a cmd prompt and type:
set _NT_SYMBOL_PATH=srv*c:\debuggers\symbols*http://msdl.microsoft.com/download/symbols;C:\Program Files\Microsoft SQL Server\MSSQL\Binn
then add your debuggers directory to the past statement
change to the directory with your mini dump in and do either:
windbg -z dumpFile.mdmp
or cbd -z dumpfile.mdmp
I prefer cdb but windbg gives you a gui.
What I would do is in either application do a "kv 500" this will give you a stack trace, if you do a "!analyze -v" it might point you to what caused it - but beware that the command guesses at the cause it isn't 100%.
To see if the symbols have loaded correctly do a "lmvl msqlservr" if it doesn't show the details of the file then do a "!sym noisy" and the ".reload sqlservr.exe" this will show you all the paths it is looking for the symbol and why each failed.
Also have a look in the logs directory you should have a text file with the same name as the dump file (.txt) this has the stack trace of the thread that crashed and if it was associated with a spid then also the input and output buffers so you should be able to work out what sql caused the crash. The dump of the pss and execution context structures will give you the spid, the database, the current command and the line number of the t-sql that caused the crash.