On 12 Dec 2008, "John Grabowski" wrote in
alt.home.repair:

That four inch pipe will be heavy when it comes down so you might
want to figure a way to brace it or catch it.

It's really a thin-walled tube and not very tall, rather than, like,
a thick iron pipe. It should be pretty light, and I think the
grinder will go through it like butter. Then I can pound down
whatever's left with a hammer. Then, next spring when the ground thaws,
I'll try breaking up at least enough of the concrete with a
sledgehammer to cover it with some soil.