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Mine Tailings Sampling Technique (7 replies)

Carmen Ibanz
9 months ago
Carmen Ibanz 9 months ago

What is the most appropriate sampling technique for mine tailings (Pb-Zn) for the characterization and recovery?

Victor Bergman
9 months ago
Victor Bergman 9 months ago

Generally you have to process all the tails as grade control in tails, stockpiles and dumps is difficult to impossible in most cases.
Tails samples (or mill material balance) from when mill was running may tell you tails total tonnes and grades.
How deep, wet and fluid are tails now? This in critical in determining how to sample. (Dry and shallow a backhoe pit MAY work, Dry and deep auger or RC drilling MAY work.).Wet and fluid is more difficult.
Beware of classification by size and density in any sampling method.
Bottom of tails surface may be difficult to determine.
If tails have changed over time (e.g. oxidized) you need assay method appropriate to proposed process (i.e. met test work)

9 months ago
Gruppen 9 months ago

We've had success sampling and characterizing mine dumps and tails piles using sonic drilling techniques (sleeved core recovery) and assaying composite interval samples from the core. Geostatistical methods can then be applied to the results to determine grade distribution and tonnages of material. Sonic drills work well in unconsolidated and wet materials and have high recoveries of the material drilled.

9 months ago
Unterstarm 9 months ago

In addition to his reply i can back that up with pictures and or user references.

Also in the past sonic was limited to unconsolidated and wet materials however time didn’t stood still and the new sonic dual wall core barrel and sonic wire line developments allow to sample even in granite, dry ore bodies or saprolite nickel stock pile material with 99% recovery.

Zander Barcalow
9 months ago
Zander Barcalow 9 months ago

Your suggestion is highly relevant. Tailings are variable by essence with mining and processing. For instance, early Pb-Zn tailings are generally pyrite-poor as pyrite was valorized for sulphur. Since a few decades, pyrite is dumped in tailings, changing radically their composition (and AMD behavior). We should talk of tailings stratigraphy here. Other variations may be observed with depth.

On the opposite, the horizontal variations are much less important, apart from water gradient, and sometimes a bit of grain size or density sorting through sedimentation or hydrocycloning.

Sampling tailings with carefully placed drill holes from deposit surface is therefore best. Collecting cores, as preserved as possible, is preferable to other approaches, as vertical variations can be sharp, reflecting past mining or processing decisions. Sonic sampling is probably the most efficient answer to the challenge of investigating a few millions of tons of old tailings. It (process all) is still the best for small deposits. 

Alan Carter
9 months ago
Alan Carter 9 months ago

In heap sampling, it is my understanding, from friends who have used sonic drills that sonic drills can go right through hard boulders within old pad and waste pile material. With a good pattern, they provide, as noted, perhaps the best method for sampling and assessing heaped material.

I believe speed and total operating cost limits broader application. Do you have site link / model information on who makes a sonic drill that is able to drill fast in hard ore? Maybe some cost/benefit studies? I find the potential interesting.

Bill Rico
9 months ago
Bill Rico 9 months ago

You can try out some of the soil sampling tools used for foundation work - look up 'geobore' on the web - they managed to core the mud in the base of the Thames river with this tool so I expect a tailings dam would be no problem. The tool fits to a standard diamond core rig.

9 months ago
Unterstarm 9 months ago

If you can get me more parameters on depth, diameter, total meterage to be sampled etc I can provide you with a cost per meter on sonic sampling.

Please click on the link to view pictures of a client applying CompactRotoSonic for stock pile sampling up to 20 meters. Cores are 4" taken with our 4x7 system (4" core barrel and 6,5/8" casing) 100% recovery of very difficult to sample material!


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