Hard Rock University Another great question. Mechanical screening such as vibrating screens or trommels tend to get clogged (blinded) when trying to screen down past 30-50 mesh. The holes are so small at that point its easy for small jagged and angular pieces to get wedged in the holes and its hard to get them out. Here is a video of one of our small trommels screening at 30 mesh: th-cam.com/video/lq3a3CwgxV4/w-d-xo.html (views at 1:52-2:26). The spiral classifier separates based on settling velocity and density so it is a great tool for 50 mesh and smaller (not very good at larger sizes such as 10-20 mesh). It can get good separation down past 200-300 mesh if set up to do so. One exception to the mechanical screening blinding problem is a Sweco Screen. They can mechanically screen down to 200 mesh and do a great job. I have seen a few in action at different sites and they work pretty good both wet and dry. They can also stack screens so several different sizes can be separated at once. The Sweco screens are limited on their throughput though and pretty pricey, where as spiral classifiers can be 5'-10' in diameter or more and can do 10's of tons per hour. Thanks for the good question!
It will all depend on the mine and the operator. Some oversized will have enough gold to re-crush and make it worth while. Other mines/ores will not. Thanks for the question.
so what is the advantage over say a vibrating screen or a trommel?
Hard Rock University Another great question. Mechanical screening such as vibrating screens or trommels tend to get clogged (blinded) when trying to screen down past 30-50 mesh. The holes are so small at that point its easy for small jagged and angular pieces to get wedged in the holes and its hard to get them out.
Here is a video of one of our small trommels screening at 30 mesh: th-cam.com/video/lq3a3CwgxV4/w-d-xo.html (views at 1:52-2:26).
The spiral classifier separates based on settling velocity and density so it is a great tool for 50 mesh and smaller (not very good at larger sizes such as 10-20 mesh). It can get good separation down past 200-300 mesh if set up to do so.
One exception to the mechanical screening blinding problem is a Sweco Screen. They can mechanically screen down to 200 mesh and do a great job. I have seen a few in action at different sites and they work pretty good both wet and dry. They can also stack screens so several different sizes can be separated at once. The Sweco screens are limited on their throughput though and pretty pricey, where as spiral classifiers can be 5'-10' in diameter or more and can do 10's of tons per hour.
Thanks for the good question!
What if you want 50 mesh before shaker table or sluice?
Im confused, where do you find any black sand and gold?
👍
do you re crush the 50 mesh plus?
It will all depend on the mine and the operator. Some oversized will have enough gold to re-crush and make it worth while. Other mines/ores will not. Thanks for the question.
Great machine.
Poo
poosmate Thanks Poo!