Jack I did a quick search about it and found.....

"The thing with rock dusts is that they are all different in their analysis according to their source parent material. Olives Australia used to (and probably still do) recommend that you apply rock dust/crusher dust to each tree site as part of the site preparation process. When I first heard of this I thought "hang on - cliche advice!" I continued (and still do) using the Albrecht method of soil remineralisation which acts on "knowns" not carte blanche advice that doesn't consider the full realm of individual site characteristics nor the respective analysis of different mineral amendments. Some rock dust is from igneous sources that range widely in its chemical properties (not to mention paramagnetic properties as well) - others people have used is from metamorphosed sediments which have a very low status indeed.

My cynicism for Olives Australia's advice was latterly supported by an independant study on the use of rock dust/crusher dust on the mineral content (available) of soils and it found that in most cases the release of minerals was that slow that it was clearly uneconomic to use the stuff. The exception was with high analysis RPR (reactive rock phosphate) where there was, albeit over the longer term (3-10+ years) some release of minerals. The conclusion of the report was that whilst use of high analysis RPR was over time beneficial and built up "capital levels" of soil phosphorus- that it was more important and beneficial to deal with the Calcium:Magnesium ratio (of Cation Exchange Capacity - as promoted by the Albrecht practitioners) as the primary means of dealing with soil mineral deficiencies and imbalances.

The idea of feeding the rock dust to worms as suggested is quite reasonable - and is something I've heard of over time - again though you can't make something into something it isn't - crappy rock dust is crappy rock dust - go for the quality.

A similar issue such as this surfaces from continued compost application and the subsequent buildup of pottassium levels in soils which "tips" the fine balance of soils. If you are doing this stuff you owe it to yourself to take it easy - go with quality - and get the analysis - just ask David Holmgren what happens when you don't - soil mineral imbalances can cause considerable difficulties in successfully cultivating healthy plants, livestock and the humans that consume them.

The best book on the subject is "Hands On Agronomy" by Neal Kinsey. Neal was a student of Dr. William Albrecht (Professor Emiritus of Soils @ Missouri Uni for about 40 years) in the 60's, and is, since Dr. Albrecht's passing is the methods foremost expert. Acres USA produced "The Albrecht Papers" which I have - they are an ideal treatment for sleeping disorders - like a lot of soils stuff very dry - Kinsey by comparison makes the subject come to life - true to his personality - very lively and full of enthusiasm. I studied the Albrecht method under Kinsey at Roseworthy (Ag. Campus of SA Uni) a few years ago now. An excellent practioner and educator with hand's on global experience.

The sampling and analysis methods used don't and haven't changed in nearly forty years unlike other labs. As such the points of relativity are very strong and comforting as such. The method is universal as the relationships between soil chemistry:soil physics:soil biota are universal. Makes the whole issue of dealing with soil problems much easier - and works on the law of the knowns and the minimum - only use what you know you need and no more - which can't be said for a range of other methodologies."

Therefore, you may want to contact Sumner Co. Rock Crusher, 555 Odoms Bend Rd, Gallatin, TN 37066; Phone:(615) 452-2710 or SOUTHLAND BRICK + BLOCK, 3201 Franklin Limestone Rd. Antioch, TN 37013; Phone: 615-834-1207. Ask for Kenny and tell him Jeff Toothman sent you. OR...SOUTHLAND BRICK + BLOCK, 700 Ordway Ave. Murfreesboro, TN 37130; Phone: 615-893-7146; Phone: 800-624-0906. Ask for Matt and tell him I sent you.

Hope this helps!
Jeff

Jackman1944,

Are you looking for a particular type of rock dust (for soil amendment)? If so, I bet the "Barefoot Farmer" (the guy that's on TV a lot) could give you advice. His Farm, Long Hungry Creek Farm, is in the middle Tennessee area. He gave a talk on this subject on Volunteer Gardener. I think he loves talking to people about things like this.

I wonder if the sources Jeff mentioned would have anything beneficial for the garden. As the article Jeff posted notes, all rock dust ain't the same.

Here is a link that might be useful: Barefoot Farmer Uses Rock Dust in Compost

YES, USE ROCK DUST, BUT MUST USE COMPOST ALSO TO GET THE BENEFITS...(YOU NEED ALIVE SOIL, MICROBES ETC.
DON'T USE LOCAL QUARRY DUST IF IT IS LIMESTONE QUARRY....WILL ALTER PH TO MUCH....ALSO DO A STUDY (INTERNET) OF BIOCHAR AND ADD ALSO....I USE AZOMITE VOLCANIC ROCK DUST BECAUSE OF 6O OR 70 MINERALS IN IT...LET YOUR FOOD BE YOUR MEDICINE....ROY

alisorganics.com about a dollar a lb delivered...