Breaking cemented gravels so I can pan it?

[Crashcrew]

I found an ancient river bed in between bedrock with gravels so hard it's just like concrete. I managed to chip a few pieces off and bring them home but how should I break this stuff up small enough to pan? I'll be sure to put up a pic as soon as I can get back up into the mountains.

 

[bobw53]

I found an ancient river bed in between bedrock with gravels so hard it's just like concrete. I managed to chip a few pieces off and bring them home but how should I break this stuff up small enough to pan? I'll be sure to put up a pic as soon as I can get back up into the mountains.

If its not ROCK ROCK hard, a cement mixer will do ya..

Here is before and after, cemented stuff, Depending on how cemented it is, it can take a while, I usually throw in some cubes of steel or some big rocks..

If its really hard and seriously cemented, you're into rock crusher territory.. You can turn your cement mixer into a ball mill I guess,
or if you are just sampling and checking. Make a quicky rock crusher.. A few pieces of pipe and a plate will do you.. Pretty cheap,
just put a pipe cap on the smaller pipe... Here is my first quick and dirty crusher, just 3 pieces of metal I had kicking around.
Its not fast, but it'll tell if its worth pursuing.