Tiling and roots---- related to post below.......effect of copper etc

I did not want to hijack the thread below about tiling and effect of roots.

So......tell me about the effects of copper and other such things on the roots.

I have never seen the addition of copper, diesel fuel, etc to tile lines .......but have heard that it works.

How does it work?

How is it introduced to the tile?

Would it work in situations such as those being discussed further below, about the rye roots tying things up..........or would the rye need to be left alone for more than one season/or two in order to have enough time to work?

Several years ago we had a tile blowout "up there on the hillside"........in the middle of the field.  Tile guy fixed it--------- and traced the problem to willow roots from a small grove....... at least 250 yards downhill.  I was impressed.

I am not interested in hearing about the illegalities of the process........I am merely interested in the functionality of the process.

Thanks.