We might want to change the title to "Rock Dust". There was a newsletter,
"Remineralize the Earth" on this subject. We had friends who brought us a
ton or so of fairly finely ground granite from Stone Mtn, it's a byproduct
of mining there and is mostly used to fill sandbags. They had a big truck,
and the pile of granite didn't take up very much room in it, but it was very
heavy.
Mixed rocks are mostly not available in Tennessee, the glaciers didn't
get this far south. We can get only limestone, sandstone, and hmmm, I guess
shale, around here. Have to look into what's in the shale, never thought
about that. Anyway, one thing that I did was go to a couple of places that
do tombstones. First I went to their old bldg and got the "mud" around
back, which was safe to handle. The newer stuff, in a barrel or in a sealed
box or room, depending on how companies handle it, is not very safe to
handle due to the dust. Also there's some weirdness about the stuff they
use to grind the granite. The older product is called "Black Diamond" and
is very fine. The company says that new regulations have them using
something less dusty, and there are bigger granite chips in their refuse. I
brought home a numbers of buckets of the stuff and put some around the
garden and various plants before getting freaked out about the aluminum
content. Yes, it's a form of aluminum they use. And yes, it's harder than
granite. It's very hard to separate out aluminum, a very expensive process
using lots of energy. Our soil is clay, which is a compound of aluminum.
and yet you don't see anyone mining the southeast for the aluminum in our
red clay. So I think it's safe to put the stuff around fruit trees and
gardens, so long as the soil isn't so acidic that aluminum is already a
problem anyway. Very acidic tropical soils have actually got problems with
aluminum poisoning of crop plants.
For you all who can get various types of rock dust, you should check it
out. For us southerners, it's not so easy to do. I've tried to make up for
the lack of minerals in our soil by spreading Planters II. The biggest cost
of rock dust is usually the transportation, so Planters is such a
concentrated source of minerals they recommend something like 600 lbs to the
acre, instead of 2-10 tons to the acre for average rock dust. The Sigma co
in Nashville carries it. Donna