North American Fruit Explorers mailing list at ibiblio

["Kieran &/or Donna" <holycow@frontiernet.net>]

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