Mine tailings under saturated/reducing conditions

[woodS]

Hello,

I was wondering if PHREEQC has the capacity to model geochemical behaviour of a mine tailings under saturated/reducing conditions using field data. I need to know first before fully committing myself to learning it. All suggestions will be greatly appreciated! Sorry if I posted it in the wrong thread.

[dlparkhurst]

PHREEQC can model the basics of sulfate, sulfide, iron, and pyrite reactions. Before you start, you should consider what is your conceptual model? Sulfide minerals are the reductants? What is getting reduced? Oxic water infiltrating? 

[woodS]

David, thank you for your quick reply!

The plan is to use PHREEQC or any other capable software to evaluate the impacts of submerging an oxidized tailings and adding a cover. Covers have been observed to result in dissolution of secondary phases and/or creation of reducing conditions (that can result in reductive dissolution of some components)

[John Mahoney]

That sounds reasonable and simple enough that it should work.  There are probably a lot of different ways to set it up.  You will need some sort of oxygen consumption process in the cover, possibly by adding some reducing material.  Kinetics and rate laws will then matter particularly if the infiltration rate is fast.


 Eventually you might want to even consider using PHAST. 

[woodS]

That sounds good! Thank you so much, John!