I have a 40 year old cast iron sewer line and there is a cleanout in the
middle of my concrete driveway.

http://i173.photobucket.com/albums/w...umbing/CO2.jpg

I believe it is a two way cleanout (with two openings) like this:

http://www.abifoundry.com/images/SV_...y_Cleanout.gif

However, it obviously has not been opened for ages, and it obviously was
cemented over last time the driveway was redone however many years ago.

I need to open it up for drain cleaning and video inspection purposes, and I
could not figure out how to open it.

A close up:

http://i173.photobucket.com/albums/w...g/P1020896.jpg

Even closer on one of them:

http://i173.photobucket.com/albums/w...g/P1020895.jpg

The cement has to be quite thin considering if you look close enough, you
can actually see the metal rim flushed with the concrete driveway, although
it is surprising that the rim is so thin...

My assumption is that right underneath this thin layer of cement is a cast
iron or brass plug I can unscrew and open the access to the pipe. My worry
is the plug threads may be corroded or stuck...but I can't even get to the
first base.

I took a chisel and hammer and banged on the concrete inside the circles, I
chipped off some concrete bits. I banged on it more, the concrete did NOT
just shattered away and expose the metal plug, it almost felt like this
concrete is much deeper.

I don't want to keep hammering at it because it will certainly ruin the
metal plug thread or wedge it tight if I over do it.

I now wonder if I am not looking at brass plugs. Is it possible that there
is no plug? That the pipes were "sawed off" flushed with the concrete
driveway and they stuffed some newspaper or whatever to plug the holes
without dropping to the bottom, then pour concrete in that space?

How do I open this up without being totally destructive? If there is
nothing there and I break things loose, it will drop to the bottom of the
pipe for sure.

My next step is to dry a masonry bit and drill down the middle and see how
far it goes, but I thought I will post this here and get a few pointers
first.

Thanks,

MC