Mesh for gems

[mushmouse]

Hi - am seeking advice.

I am considering putting down a section of expanded mesh in between one set of riffles at the tail end of the sluice box. It wont be a large piece ( 120 x260 ). Primarily its to grab any stray gems that may make their way down. The size wont be large - most likely a 5mm ( or equivalent ) opening on the mesh and I would have it so the cavity side faces the flow.

I'm not phased too much about any heavies build up at the tail end as I would keep an eye on it and I don't mind the clean ups.

Is the expanded mesh a good solution for any stray gems or is there another sheet design/product I could put in here that would work better? I'm not worried about the gold as that seems to do what is suppose to do up at the top 12 to 16 inches...

Thanks in advance. A

[shivan]

An interesting idea, but i have a feeling it may need a little fine tuning.
Most sluices i have seen setup with riffles and expanding mesh, have had the expanded mesh at the top of the sluice. The reason i believe for this is because of slower moving water flow at the head of the sluice. I could be wrong, but if you have expanded at the tail end of the sluice, the water flow and material may be moving to quickly for the expanded to do its job properly.

Saying that i could be way off the mark. Experimenting cant hurt. I will see what info i can hunt up.

[jeffu]

Hi All.

I'm going to throw my bit in. I can't comment on the use of expanded metal for gems, but for gold I can talk all day.

In gold only sluices/highbankers, expanded metal and hungarian/clarkson riffles DON'T work well together. There is to my knowledge, only one manufacturer that has got it right, that's Heckler Fabrications in the US. If you want to see what I mean look up Heckler Fabrications and have a look at how they have setup their 1020 Highbanker.
Compared to Hungarian/Clarkson riffles, expanded metal requires HALF the waterflow and HALF the feed rate. If you have both together in the same sluice, you will either clog the Hungarian riffles or completely scour the expanded metal.

I know that Joedigs has been working on a riffle system for his sluice specifically for gems, pretty sure he uses only expanded metal (a fairly coarse one). Not sure where he is at the moment, haven't been able to contact him for over a year. Shivan might have a better idea how to contact him.

Jeff

[mushmouse]

Thanks guys for the feedback. That was helpful and I will checkout the 1020.

As I use a bilge - my volume is always the same so I rely primarily on the pitch of the hopper and sluice to control the exchange. I have Hungarian over carpet ( but this season will be Miners Moss - woohoo Jeff    : )) 

 As you know, Reedy is a nightmare for tin and I don't want to compromise my gold retention in the off chance of a nice sapphire or 2. My HB is not precise or clean by any shot, I always have some tin and quartzite left behind - but among that is all the gold that went in as well, so I am ok with that. HB clean out is about 5 minutes turnaround - cons are taken home.

I guess I can play with some expanded mesh and see how it goes.( 7 sections in the ladder to pick from) It's something that I would like to take in and out depending on the area. Some places in the creek are high 'gemstone' locations and at times I have come across deep gutters in the creek full of large Cassiterite and gems. In the past I would shove a catch pan at the end and have found well rounded gems that have come through with the tailings. With mesh or whatever as a bottom end final safety net, I thought it may be neater just to pull out, check for pretties, belt the tin out of it and shove it back in...
( plus getting busted using a catch pan is such a downer .. )

[golddiggerart]

If you are going to use the expanded mesh with Hungarians then put it up near the top and the bottom only a small amount, then test that to see which catches gems. Trial and error...
Just my two million dollars worth.