Production time is 13mins 9secs + travelling time. Assuming things don't change when it goes live, cost is 20K gems & it produces 40K gems over a one year period.
I was a little suprised to see there doesn't appear to be a limit on the number of gem mines you can purchase (other than the size of your wallet, I suppose). I managed to build two on the test server & I presume I'll be able to build two more after 6 months are up. Of course, the test server is likely to be wiped by then, so I'm only guessing


 
			 
			 
 
			
			 Originally Posted by ben001
 Originally Posted by ben001
					
 
					
					
					
					
				 It runs dry after one year & with no way of refilling it, it becomes useless.
  It runs dry after one year & with no way of refilling it, it becomes useless.