Mine Tailings as Aggregate 1

[JamesPeck]

I am working on a mine tailings reclamation project, and am considering using the tailings as aggregate in a soil cement channel lining. Does anyone have any experience with, or know of any good references regarding the use of mine tailings as aggregate? I am particularly interested in tests for chemical compatibility.

Any input is appreciated.

James Peck

 

[BigH]

Must be as the fine aggregate. Be careful where you get the tailings; they can be quite fine and slimy! I'm not sure about what you say, but will check with a colleague of mine - if I can still find him.

 

[dbuzz]

I've observed the use of tailings as a constituent material of a mine backfill paste.

It was a notoriously difficult material to work with. It required significant drying, blending and testwork to ensure consistancy.

 

[Ron]

Be careful using mine tailings. A lot depends on what is being mined. Some tailings are expansive or can react with cement to give you results you didn't want! Copper, gypsum (phosphates), and others can be problematic.

 

[Backfill]

Often tailings are relatively fine, with sand being the high end and slimes the fine fraction. Depends on the age and type of process. A hundred years ago, many had coarse fractions of 3/8" or so, but the tails are pumped or sluiced, so aggregate doesn't much fit.

SME (Society for Mining, Metallurgy & Exploration -

http://www.smenet.org)

has a number of publications which address tails characteristics. If these are relatively 'clean', sans slimes and clays, they may do. Often, metallic mineralization and attendant rock alteration result in significant fines and clay fraction by the time one has ground the host rock to something which will allow liberation of the metal. Think mill slimes. You may not have too much success in developing flow through them, though piping alongside can be a snap. They also are relatively easy to excavate and one build wick drains or channels using geotextiles.

These are a couple of ways of looking at the problem... . I wish you success with the problem.

Ralph R. Sacrison
Sacrison Engineering

http://www.sacrison-engineering.com

 

[BackfillTek]

Tailings can be used as aggregate in soil-cement, but as mentioned above it is important to observe the chemistry and mineralogy.
If the tailings are from a dry pond, excavation will result in varying particle size distributions. A laser analyser will help to classify the material. In general, coarse tailings will produce higher strengths, look for material with less than 10 - 20% passing 20 um if possible. If the material is to be pumped, typically 15% passing 20 um produces a good carrier fluid.
Some minerals such as gypsum, ettringite & jarosite attack cement bonds over time. Early strengths can be misleading.

Good luck,
Ryan

 

[Kivi]

Yes you can use it as an aggregate for soil cement, mine backfill people have been using tailings underground for 50 years. the material has to be characterized and basic testwork has to be performed. Pending your budget, this can all be done yourself, by a consultant to do it or teach you (

http://www.parinn.com)

or a geotech company such as Golders (if you have unlimited budget).