Dewatering: Thickening, Filtering, CCD, Water Treatment & Tailings Disposal

Dewatering: Thickening, Filtering, CCD, Water Treatment & Tailings Disposal 2017-04-04T06:57:46+00:00
  • To participate in the 911Metallurgist Forums, be sure to JOINLOGIN
  • Use Add New Topic to ask a New Question/Discussion about Thickening, Filtering or Tailings and Water.
  • OR Select a Topic that Interests you.
  • Use Add Reply = to Reply/Participate in a Topic/Discussion (most frequent).
    Using Add Reply allows you to Attach Images or PDF files and provide a more complete input.
  • Use Add Comment = to comment on someone else’s Reply in an already active Topic/Discussion.

How Silver in ARD Acid Rock Drainage AMD (10 replies)

John Koenig
2 years ago
John Koenig 2 years ago

Effects of trace silver concentrations in mine waste on ARD production

I know about the antibacterial effects of silver on human-based microbes - this has been around for centuries. I just learned that silver appears to have the same effect on acidithiobacillus ferrooxidans; e.g., bioleaching pyritic ores with silver content can be problematic with Acid Rock Drainage. Can anyone recommend a technical paper or reference that explores this phenomenon in straightforward language that a mining engineer could understand? Thanks

Victor Bergman
2 years ago
Victor Bergman 2 years ago

I seem to recall some work published in the CIM journals in the 1980's and 1990's. As silver is considered a contaminant there maybe some work done published in Groundwater and Groundwater Monitoring and Remediation. BTW do not sell yourself short - some of the most intelligent people (not all mind you, ;-), especially when I was escorting them home from the bar) have been mining engineers.

John Koenig
2 years ago
John Koenig 2 years ago

A bio-leaching expert & friend noted that the presence of chalcopyrite is an interference (which is OK for bioleaching situations) and that chloride negates the bactericidal effects of silver as well.

Bob Mathias
2 years ago
Bob Mathias 2 years ago

Chloride is a double edge sword though, adding it also mobilizes many toxic metals. Care must be taken if you are thinking of adding to the mix. Containment would be recommended.

Maya Rothman
2 years ago
Maya Rothman 2 years ago

Please understand that I'm not trying to oxidize pyrite: just the opposite. Understanding this mechanism might help to explain why some pyritic waste rock dumps or tailings ponds go acid when others do not. Silver content is not a constituent typically included in acid base accounting, eh? Maybe it should be (for metal mines).

Alan Carter
2 years ago
Alan Carter 2 years ago

I just meant specifically chloride. I understand the role of silver as an anti microbial. I do know other experiments have been done to control the bacteria in question. Some have included using waste milk so that the acid generating bacteria is out competed by other flora, for example, in ARD environments.

Tony Verdeschi
2 years ago
Tony Verdeschi 2 years ago

Maybe this will help. The microbiology is well within your reach!

https://microbewiki.kenyon.edu/index.php/Silver_as_an_Antimicrobial_Agent

The article states that the effect is due specifically to Ag+(aq), so Cl in solution will limit the free Ag+ to the solubility limit from AgCl, which, if I did the arithmetic correctly [SQRT(Ksp)* MW silver] would be about 1 mg/L in dilute solutions. That's a pretty high Ag concentration

Alan Carter
2 years ago
Alan Carter 2 years ago

This is great background - thanks. Has anyone seen a correlation between ARD production and silver content in humidity cell tests of pyritic tailings or other mine wastes?

Tony Verdeschi
2 years ago
Tony Verdeschi 2 years ago

The correlation will have to do with the origin and nature of the ore body from which the tailing is developed. There are certain styles of mineralization - obviously epithermal precious metals, for example, or the "cobalt association," and in quite a few supergene-enriched in the Cordillera (including the famous bonanza silver deposits in the western US). Of course, in those cases one would not expect to see Ag associated with high pyrite, unless it was a limited-enrichment example, like perhaps Copper Cities (see Guilbert and Park). You would expect to possibly see low levels of Ag in porphyry coppers. A review of geologic reports and exploration data (or production data) would probably identify specific targets to look at.

Helena Russell
2 years ago
Helena Russell 2 years ago

My only thought on this is that microbial oxidation of pyrite generates thiosulfate, which can dissolve silver. In certain wastes, it may be possible for the resulting silver-thiosulfate complexes to reach toxic concentrations, thereby limiting the extent of sulfide oxidation. This idea makes for interesting speculation, but I doubt that it would explain much more than a few cases, at best.

David Kano
2 years ago
David Kano 2 years ago

Interesting work at Michigan Tech found that silver sulfide minerals would interact with mercury cyanide, dissolving silver and precipitating mercury. http://digitalcommons.mtu.edu/cgi/viewcontent.cgi?article=1593&context=etds

Please join and login to participate and leave a comment.

BUY Laboratory & Small Plant Process Equipment

We have all the laboratory and plant equipment you need to test or build/operate your plant.

ENTER our Mining Equipment' Store

We Sell EQUIPMENT for all types of Mineral Treatment PROCESSES and Laboratory Testing needs

Have a Mineral Processing QUESTION?

Come in, ask your question

911Metallurgist Community Forums

Talk to other metallurgists and be helped.

Need ENGINEERING Services or Plant TROUBLESHOOTING?

We can IMPROVE ALL PLANTS / Mineral Processing Engineering & LABORATORY Ore Testing

911Metallurgy Engineering

Contact us for process engineering, metallurgical investigations, plant optimization, plant troubleshooting, needs. WE “FIX” METALLURGY.