mining tailings wate treatment options

Question

I am building a model of mining operations. The example mine does all their rock crushing and griding in enclosed spaces and uses dust control vaccums to limits tailings dust.

How can I model the treatment of tailings with and without dust collection? The dust will be reburried in a closed mine as part of the overburden. I have found a paper characterizing the  chemical make up common mine dust. Should I have these as elements as elementary flows back to soil? If the dust is collected and the deposited, how can I model that?

The closest process I have found is:  market for non-sulfidic overburden, off-site | non-sulfidic overburden, off-site | Cutoff, U

Would one version have the elementary flows going to water and the dust collection one going to a dump site?

In addition, how is this handeled by the model? I assume it is how the LCIA method treats different wastes. If I create a tailings deposit product (blue cog) is the impact calculated differenytly than an elementary flow (green leaf)

Answer 1

Hello Kaunis,

I agree with the first method you propose. Modelling the elementary flows to soil will give a good approximation of the impacts from reburying the tailings. It should be considered that not all elements will go directly into eco-systems, or impact human health, but it is a valid approximation, and if anything overestimates the impacts, which is a more valid method than underestimation.

The process you have found does not include any environmental impacts, other than land use and land transformation. I would investigate some other final disposal processes for tailings, that includes leachate as well as land occupation. Even though it might not be a precise chemical composition, it will better estimate real impact.

The system comparison would then be between the direct elementary flows to soil (green leaf) and the waste treatment flow (red trashcan)

Using a product flow would not be relevant here, i do not think.

Hope this answers your questions, good luck.

Comments

Thanks for the response. I have done more research and it turns out modeling mineing tailings is complicated and seems like it is still an evolving field. I will post some links in case any future searchers have a similar question.
https://www.sciencedirect.com/science/article/pii/S0921344922001926 - comparison of several tailings lcas

https://www.sciencedirect.com/science/article/pii/S0892687522000917 description of transportation model of tailings flow through a tailing pond

How exactly are the red trash cans treated in the openLCA model? I see the inputs I have selected as raw materials have characterization factors, and emissions to soil/air/ water also show what impact categories they impact. Is all waste treated the same in the model? Just by weight/ reference value?

It is interesting that dry stacking for tailings seems to be gaining popularity as a "sustainable", but there are only one or two LCA papers published on the subject. For my study I will model one version with the waste deposited back underground, with only the land use change as an impact, and the other as emission to soil water.