7th axis rotary table

[vre]

Hello.
I want to build a rotary table for a 6 axis big milling robot.
I will use a servo about 4kw with gear reduction.
Table must be able to hold 10-20tons load for example
a big marble block for milling a statue.
What type bearings are good for rotating axis and what gears with
no backlash for reduction?
Something like this https://youtube.com/watch?v=jeJwq924eMQ

Thanks