buff on mines

Ok got a question.

If you buff a mine.. does it produce 2 times as much or does it the amount drop also 2 times as fast.
for instance:

I buff my gold mine which normally produces 4 ores a minute and takes 4 ores out off the mine.
If I buff .. it will produce 8 ores but will it take 4 ores out off the mine or 8?

Regards

Buffing doubles the production without costing any more than normal.

The mines, which should be at level 5, will empty 5 times faster than level 1 mines. However, you will get double the ore.
A level 5 copper mine lasts about 9 hours. Just enough time for a friends basket to last.