can you just a walk right into Mexico? Say, from, some strange place in the desert?

Yes. But be careful to not get caught coming back.

just go through customs, unless your carrying a huge bag of maryjane

pearson wrote:That one was built by an American chemcial company that mines feldspar on the mexican side. They don't mine it in the US because the pollution controls are too stringent. From Mexico they dump shit straight into the river.

What kind of pollution can you get from mining feldspar? I'd guess the silt that naturally enters the Rio Grande is half feldspar, or clay derived from weathering of feldspar. Was there something else about the mine?

pearson wrote:It was fluorospar, not feldspar.

That makes more sense, since feldspar is so common; but I still wonder how this caused polution, unless there were small amounts of sulfides in the deposits, or it was just silt that washed down from the tailings pile. CaF2 itself is quite inert.

I live in a state where mining companies dump tens of million pounds of NaHCN and CaHCN on the ground every year. That's pollution I can understand.