Gravity Separation & Concentration Methods

Gravity Separation & Concentration Methods2017-04-04T06:57:23-04:00
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Deister #88 coal tables compared to Deister #9 gold tables (4 replies)

1 year ago
CA 1 year ago

Does anybody know of the differences in the table deck/riffles of the old Deister model #88 coal concentrating cables compared to the Deister model #9 tables?  Would the coal tables work for gold applications?  Are the head motions the same?

Deister doesn't have any information on their coal tables listed on their website.

Thanks for any info that you may have.

1 year ago
David 1 year ago


I chatted with 

88 Deck riffles are higher for handling 3/8" coal particles. The 88 Deister table is not recommended for gold applications.


#88's are different from #9's both in configuration and in operation. Besides the obvious appearance difference, 88's are usually suspended from the floor above while 9's are usually floor mounted, the motion and speed of operation is different. 88's operate at a slower frequency then 9's, and yes the head motion is different. Also the basic deck configuration is different (riffle size, spacing, angle). Much of this is subtle, but can have an impact on performance.

That said, the is no major reason why 88's could not be used for gold applications, especially double and triple decks. I would look at speeding up the motion, or at least putting it on a VFD drive. Also consider using a set of 88's for a primary/rougher function followed by a single 9 in cleaner function.

Also you can replace the deck with smaller, closer spaced riffles.

1 year ago
CA 1 year ago

Thanks David.  We would be using the table as a rougher to separate the heavy sulphides from the gangue.  We achieve good separation on an RP4 table in testing, but we need a production table.  The idea is to send the sulphides to a separate recovery process rather than leaching it together with the rest of the ore. 

I am also considering Reichert Spirals, but I don't have any experience with either.

1 year ago
SmartDog 1 year ago

Spirals will work well also, but do require more head room, also are more difficult to set up and adjust, primarily do to not been as easy to watch.  Tables can be adjusted on the fly by changing tilt, stoke, water, and even adjusting the cuts to make a final con, a middling, and a tail.  That said, spirals do an excellent job and properly set up and maintained can work very well.  


But in my opinion tables tend to be more forgiving


1 year ago
oro 1 year ago

Concentrating milled ores with gravity concentrators especially tables and spirals will achieve best recovery by concentrating the head feed in 2 stages and pre-screen the corresponding fraction.  Example (in a continuous operation) screen the first fraction (rougher) at -30 mesh and then screen the rougher discharge at -80 which runs across a good finish table.  Simple rotary screens (wet) work well or a high frequency deck type for large capacity (feeding several tables).  To concentrate the gold bearing sulfides be careful not to grind too fine.  You can also use a centrifuge in place of the table or as a scavenger at the end.  For roughers I use 16" diameter horizontal barrel spirals (bank of spirals) with an 80 mesh barrel screen attached to the end which essentially acts as a rougher / screener in one.    

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