How to stop mines from filling with rain water?

[(>♡.♡)>]

Every time it rains, any holes I have dug are completely filled with water. So I have to dig a completely new way to my iron deposits. Is there a way to prevent rain filling things up, or to drain out the water it leaves?

[Lions_Den]

Place a hatch over the entrance and leave it closed when you aren't going through it. Water won't go through the hatches.

[(>♡.♡)>]

There is no entrance, its just a big pit

[Ruckus]

then build a roof :) don't make an open pit, have one small entrance with a hatch....... i built the entrance to my mine from the inside of my house :D nice and dry