“Gravimetric What?”

Understanding Gold Recovery Terminology Can Be as Perplexing as Learning How to Recover Gold Itself!

How to recover gold? Sometimes, listening to highly educated/experienced people in the gold recovery field can get a bit confusing…like the term “gravimetric properties” which I recently encountered…I had to smile.

Likewise, if you read the gold publications you will see all kinds of claims by equipment manufacturers as to how efficient their piece of equipment is, and why you should buy it. It kind of reminds me of fishing lures…designed to catch fishermen…but not necessarily fish.

The fact is, while some devices are quite ingenious in how they go about recovering gold, they are pretty much all the same in that what actually makes them work, is gravity…and gravity is available to all of us…for free!

 Now it is clear that some devices do work better than others for various types of material. It is also clear that seemingly every month, a new device is introduced to the gold mining community that is the “secret weapon” to gold recovery. It will recover everything from large nuggets to 400 mesh gold, and without classifying!

Some miners are quick to jump on the bandwagon and purchase that new piece of equipment, especially if it is being touted by the local gold expert who just happens to be selling that same gizmo!

For a lot of small scale miners who can’t afford to purchase the latest gizmo, they try to build their own, and sometimes with similar or even better success.

Isn’t it interesting though, regardless of the device used to extract the gold from the paydirt, it almost always comes down to panning by hand…with a  gold pan…you must become a good gold panner.

Besides the centrality of gravity, another big piece of science that is important for gold miners at all levels to understand is the importance of “Hydraulic Equivalence”. That is the amount of force, usually in the form of flowing water that is required to move objects of the same size, all other conditions being equal. What we all want is for only the gold to remain in the sluice. That is what a cleanup is all about…clean up the material so that nothing is left but the gold.

Because it is so dense and heavy, gold will always require a greater flow of water to move it than a piece of quartz rock or other material of the same size. The trick is to apply just enough hydraulic force to move the lighter materials, and leave the gold behind. This is the real reason behind the axiom: “classification is the key to gold recovery.”

Whether sluicing or panning, classifying (separating) the material by size will dramatically improve your recovery efforts. Why? If the pieces of material are the same size, the lighter material will be washed away before the gold…likewise if you crank up the water flow enough to wash out everything except the large nuggets, the smaller sized pieces of gold will have washed out of the sluice. So, separate out (classify) the larger size gold pieces ahead of time.

What you learn after a while is that almost any device can capture the big nuggets. It’s the small stuff that is hard to recover. That’s why Gold Cube’s advertising slogan is something along the lines of “If you get the small, you get it all!” It’s true, and it’s because of hydraulic equivalence.

Doc at Gold Hog, I believe, has done a good job of helping us all understand this concept through several of his videos and essays. Hydraulic equivalence, is the technical term, but classify, classify, classify is what you need to do.

Whether you are using a trommel, a jig, a water table, a centrifugal concentrator, a sluice, a shaker table, or a highbanker, you are using gravity to separate the gold from everything else…each of these devices relies on gravity to make them work.

How gravity affects gold, the material it is embedded in, and how gravity affects the functionality and efficiency of your equipment, is understanding the “gravimetric properties” of the gold recovery process.

So the next time your local gold recovery expert starts to spout off with all his scientific terms, throw back a sentence including the importance of considering gold’s “gravimetric properties” (“Well you know, since gold is 16 times heavier than water, one must consider the gravimetric properties of the material being processed and the equipment being used to separate the heavies from everything else when designing a gold recovery system…dude!”)

Don’t be surprised if you get a blank look in return.  

For a safe place to ask simple questions without a lot of confusing terminology, visit GoldProspectorsSpace

Michael V.

President iPan4Gold


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