Slate Miller Table

[kazcoro]

Hi all. I buit a recirculating sluice to set in the garage, and after seeing a drywasher in action, sold the sluice. Kind of hard to see my creation leave, so I have been researching Miller Tables. I decided to build one. This fits my bill for fine gold recovery, and clean up. Also quenches my thirst to build and create.

I started by locating plans on the web for a table. While they don't include slate, the basic idea gave me most of the info I needed.

The next step was to locate some pool table slate. I have done that. I found a large piece of 1" slate at a billiards dealer here in town. Nice to live in a large city.

Then, I cut the slate into a 8" by 30" piece. I only have a cheap Home Depot tiel saw, and it took a long time to cut it up. The motor doesn't have the torque to cut continuosly at ANY feed rate. But, I got it done.

Now, I am working on constructing the water flow and stand portions of this monstrosity.(Pool table slate, even only 8" wide is really heavy.) As I am sure you can all imagine.

Now, my question is this. Should I sand this slate down at all? There are a couple of small scratches in the bed area. Should those be smooth? I see "tooth" mentioned periodically in the construction of these tables. Does that mean that I want to rough up the surface a little? Maybe hit it with some 200, or 400 grit paper and a random orbital sander? IF so, I know I want to do this before I assemble the bed to the frame.

Any help is greatly appreciated.

 

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[Color-blind]

I dito this question. I am having good results with my unsanded slate but, could I have amazing results with a sanded surface?

 

[kazcoro]

I dito this question. I am having good results with my unsanded slate but, could I have amazing results with a sanded surface?

I have a couple questions for you. If you don't mind, that is. How big is your table? How small of gold are you catching with it? Have you panned your tailings to see what the recovery rate is?

 

[Goodyguy]

Not recommended to use coarse sandpaper to rough the slate up. A wet sanding with 400 wet or dry sandpaper would be ok if needed to smooth out deep scratches. Typically slate is honed to 10/1000 of an inch. Gold does not need a rough surface to catch onto. The density of gold is what keeps it from washing down the table provided the water flow is not too fast or the angle of the slate too steep.

A rough surface will actually cause gold to want to lift up into the flow due to water getting underneath it. The flatter the slate the better, that is one reason why slate works better than any other surface. Another reason is that slate is slightly porous and allows water to soak into it just enough to cause a sort of suction at the surface.

If water beads up on the slate that's bad. Wash it with dish washing liquid then rinse. You may need to use 91% rubbing alcohol to get any residual oils off the surface. If you have to, wet sand with 400 to open the pores.

GG~

 

[Color-blind]

My table is 20" wide by 30" long (Wish the bed was a little longer but that was the size of slate I found). It's catching some really fine stuff, fine enough that you can't really see it until you brush it together in a pile. I run the concentrates about three times through and each time I continue to get gold but I also get less and less each run. I'm not running recycled water with jet dry as of yet its straight house service water so once I get it finished to where it is reclaimed there should be a noticeable difference in the gold left behind on the table. Goodguy has given some great advice that has helped me such as: Dropping the bed angle, slowing up the H20 and paying attention to where and how I introduce my concentrates onto the table (Not to close to the water inlet, doing that was just pushing everything off the table, gold included). I'm trying to figure out how to attach pictures (Advise please), and when I do I'll send pictures of my finished table and the gold I'm getting. Goodguy has pictures of his table under another thread, it's very nice & a very clean design.

 

[TerryC]

NO sanding! The naturally rough (porous) surface makes slate the ideal medium for the table. You cannot see the pores because they are small. If you sand it, you will destroy the reason slate is best. TTC