Mineralization Question

[Anton Alferness]

Let's say I have access to a few dozen piles of mining tailings in Australia... bits, pieces, chunks, whatnot. And let's say I have the budget and process tools to crush said tailings down to a nice fine powder, suitable for ambient capture of CO2 given the basalt, limestone, olivine or magnesium content of said tailings.

Question: doesn't the crushing of tailings down to a powda (yeah, I said powda cuz I'm Australia) actually release CO2 that is in said rocks? And how would one go about measuring this for carbon accounting purposes? Is this or is this not a conundrum?

I sincerely appreciate any and all responses re this question.

Thanks,

-Anton

[Andrew Lockley]

It's the fuel used for the grind you need to worry about - or the fuel used for the electricity, if it's fixed equipment.

Andrew 

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[Anton Alferness]

Let's assume that part is accounted for, but I agree the processing has its own footprint accounting. 

What I want to understand is does crushing rocks / mind tailings release CO2 and if so how much and how that could be measured and accounted for. 

[Eric Matzner]

Hi Anton, if you are asking about the breakdown of the minerals themselves (not the emissions from grinding) causing a release of CO2, the answer is no, the crushing of the minerals does not cause a reaction that releases CO2 from them. The CO2 that is there as solid carbonates (i.e. MgCO3) is one of the most stable forms possible and the exposure to acidic rain / the environment for Mg carbonates can even increase the amount of CO2 stored:

"The solid residue analyses showed that the fixed CO2 content of the carbonates that had been exposed to nitric acid was even higher than before the treatment."  - Stability of calcium carbonate and magnesium carbonate in rainwater and nitric acid solutions (Teir 2006)