When you say 'appeared to hit ground', did you actually see it hit, or did
it go behind a hill?
I haven't heard anything about this event, but from your description, what
you saw was an object weighing at least tens of kilograms falling from
space. Such objects are usually satellites or other space junk, but
occaisionally natural meteorites. It was unlikely to be a piece of Mir,
since Mir is in a high orbit and is fairly disciplined about sending its
junk back to Earth on spacecraft, rather than simply throwing it away.
Most satellites are of sufficiently flimsy construction that they burn up
before hitting the ground. Re-entry would burn off at least an inch or two
of solid steel, and few spacecraft parts are so hefty. When Skylab
re-entered, the only part that survived was a radiation-proof safe they
kept their film in. In particular, fuel cells are not dense enough to
survive, AFAIK. On the other hand, it probably was a Soviet or Russian
object. They sent up a lot more stuff than the rest of the world put
together, and they weren't as fastidious as other countries about not
letting things fall out of orbit.
They're dropping things on your head because the odds of actually hitting
anyone are pretty slim, and even if they hit someone, the chance of being
held legally responsible is small, and even then, the cost of losing a
wrongful death suit are far less than the cost of launching the payload in
the first place.
--CarlF