On Thursday, January 24, 2008 at 10:32:05 AM UTC-6, Joe wrote:
My sump pump stick about 3 inches over my sump pit. I would like to
cover it with some heavy material so it muffles the sound and provides
somewhat of a seal. The only thing I can think of is to cut up a piece
of tarp and glue some of that egg shell foam sound proofing material
on top. It doesn't need to be pretty. Any other ideas that might be
more effective?

Maybe you can build a wood box and line in with Stone Wool insulation and then place the box over the sump pit?? That's my idea.