I have 9 tons of coal on pallets outside under my deck. All are covered with plastic to keep the rain off, but suspect they are all filled with water before delivery. My auger pipe rusted out last year due to water in the coal, and I do have lots of holes in the bottom of the coal bin. I vacuum the water out of the washer pan that I have under the coal bin. Works fine.
I am cutting the stitching now, and this seems to work. However, its take more time than just cutting the tops off the bags.