Recycled Stone Dust Amendment

[sticky367]

What up icmag !
so I noticed a large container of wet rock dust out back at a business drying in the sun and inquired about it. They said that it was a byproduct of drilling and fabricating all different kinds of stone pieces. I'm talking basalt, granite, limestone, and many others.

I've heard of glacier rock dust being used, does anyone know if this is a safe thing to add into a mix?

what type of nutrients would this contain?

either way ill try to do an experiment and get back to you guys. cus i know you like that stuff

 

[Coba]

Don't know what kind of chemicals they would use for polishing the granite and basalt... if any? it's a great find if chemical free.

 

[sticky367]

I had not thought about that. They do polish but i think the dust is just from drilling. I asked another resource i have he said its hit or miss depending on the materials used. On one hand it could be good stuff on the other there could be high amounts of elements that are not desireable in soil.

 

[Luther Burbank]

Sticky, if they're just grinding and polishing without chemicals, nice acquisition! Here are some personal notes, my apologies for the lack of source, partially this is older notes or personal maths done.

The typical composition of rock dusts is as follows (note that elements in large amounts appear in %, those found in minute amounts appear in mg/kg):
Calcium(Ca) - 6.44%, Iron(Fe) - 10.5%, Magnesium(Mg) - 6.54%, Sulfur(S) - .21%, Potassium(K) - 1.25%, Silicon(Si) 21.6% - all other micronutrients and Phosphorus occur in measurements small enough to be measured in mg/kg.

Limestone is excellent for Calcium(Ca) and to a differing degree Magnesium(Mg). What we call Dolomitic lime merely has a higher percentage of Magnesium attached. I feel dolomitic lime has been made into a misunderstood boogie man, when it's simply a humble rock dust which has its uses. Not on heavy clay soil at all, but lighter and sandier soils benefit from the extra magnesium.

You might ask more specifics from the place; my bet is the workers are rock heads and knowing specific rock types will allow you to figure what elements they contain.

Basalt and Granite are related. Granite just cooled slower inside the earth and thus has a higher percentage of Oxygen(O) and Silicon(Si). Because Basalt cooled quicker it has a higher percentage of heavier elements.

The rock names tend to be kinda fluid and composition of basalt varies. I took the average percentages of 3500 basalt samples and then calculated each elemental percentages from their molecules. A rock might contain 6.84% MgO, but once that Oxygen atom is broken off you're left with 4.12% Magnesium.

Avg composition of basalt: O - 44.29%, Si - 23.33%, Al - 8.47%, Fe - 8.32%, Ca - 6.87%, Mg - 4.12%, Na - 2.20%, Ti - 1.12%, K - .93%, Mn - .20%, P - .15%.

It'd be pretty hard to overdo it on rock dust, but do keep in mind, the finer the particle the more surface area it has, and thus the faster it will break down.

 

[soil margin]

As luther and coba said this is a sweet find if chemical free, I would def put that to use as a soil amendment.

 

[sticky367]

I got a bag of the rock dust. Was thinking about running a soil test with control and popping some seeds in it that I have laying around (SFV kush x mystery male, and Vtown sour D x same mystery male). Would clones show more consistent results? I don't want to buy clones.. any input would be helpful.

 

[Luther Burbank]

If you're running a test with controls you should be using the plant or multiple plants. Multiple would be better, but running a cutting in each soil type you want to test. So you could pop your seeds, run 3 or 4 cuttings of each in your soil types for a better controlled experiment.

 

[sticky367]

Okay, makes sense. Thanks for the response Luther. I'll post results once I get things together.

 

[Luther Burbank]

Looking forward to it! You might want to make a thread in the Side by Side experiments forum. Controlled experiments are always welcomed.

 

[EclipseFour20]

I would send some samples for testing....byproduct of drilling and fabrication could equate to contamination of chemicals/petroleum products used.

You never know unless you were there...I guess.

 

[Mikell]

Drilling re: using drillers mud, potentially. But I think you're refering to drilling holes in sheets of granite.

If they're using laminated granite, e.g. edging, a very small fraction of the mud/dust would comprise the epoxy used to bond granite, but it would be a neglible amount.

 

[sticky367]

I would send some samples for testing....byproduct of drilling and fabrication could equate to contamination of chemicals/petroleum products used.

You never know unless you were there...I guess.

I know the guy in charge of the shop. I was trying to avoid spending money on testing. In my limited experience testing is a great tool but the proof that it works is in a grow test...I wish you could get a flat rate per year or something for testing haha I would be sending all kinds of stuff in.

Initially I had the idea to try this material because I saw grass growing out of it while it was still damp. That stuff will grow anywhere though.

 

[EclipseFour20]

Chemical contaminants and/or heavy metals would be my primary concerns. Certain plants are desired to use in soil remediation for their abilities to pull contaminants and heavy metals from the soil...and who would have known that cannabis plants are very efficient in performing this task.

To rationalize paying for a test, how many pounds will you "score" for free?...Now take the cost of the test and divide by the # of pounds you scored, and should be your per pound "cost" for the rock dust (before transportation and storage). Scoring a few hundred pounds of killer rock dust and paying $50 for a test might not be such a bad deal. Finding out the rock dust is high in uranium is probably an even better deal at $50!

You never know...until you ask.

 

[ct guy2]

Will you post a test if you get one? I can share one with glacial rock dust, azomite, and basalt as a comparison.