Any tips on how to deal with cassiterite?

I have been doing a little sluicing in a creek that carries gold, in with a ton of cassiterite. I have an Angus McKirk AU Boss sluice. I'm finding the riffles filling up completely with cassiterite in no time... maybe after 10-liter bucket of wash is put through. What's the best way to deal with this? Cleaning it really often? It's just so tricky to get the balance and water flow just right that it seems like a very time-wasting way to go about it. Would you be worried about loosing gold when the bottom-most riffles start to fill up with cassiterite?

Thanks!

M

Welcome aboard mfdes

Not sure exactly what cassiterite is but many places in Vic have black sand and very fine white grit that will show as you run your sluice (I use a Foreman).

If the sluice is retaining this type of stuff then I consider it to be doing its job, the gold being heavier should in theory displace the grit and black sand. The sand and grit should similarly be displacing smallish bit of quartz, however if your riffles are filling with this stuff only then I'd be inclined to clear it often to be on the safe side.

That probably doesn't help too much but I'm sure some more knowledgeable will also respond.
Cheers Tom

Cassiterite is a tin oxide mineral, SnO2.

You can test for sure if its tin by using zinc and hydrochloric acid. Pure tin is $21,000 us a ton at present. Maybe it would be not a bad idea is keep and store the Cassiterite on the side, when you scratch up a far bit you may be able to find a buyer.

black sands are a good sign mate means your sluice is doing the job it should be, I ahve the same trouble down in hepburn so much gems and black sand you really need to clean out often. You dont tent to get as much buildup with a raised riffle design rather than a drop riffle but at least your clean out only take a few minutes. Might be worth filling buckets of cons and taking it home to process in a bluebowl

Classify til you hit the screen that gives most gold per scoop or shovel. I am guessing that your gold is more like flour gold than +2mm go down to a 1/20 screen abd see what you get. I had a spot that was lots of black sand with very fine gold. Classifying down worked for me..

Good luck with it

Cheers,Tone

I was chatting with an old prospector in Bunnings today and he was getting some aluminium fly screen mesh which he swears by using it as the smallest classifier around. He says it works wonders with the flour gold. Anyone heard of this before? or was he chewing too much jerky? :/

I have considered buying the brass screen ,but was $80 metre. Alluminium screen would wear through in 10 minutes, if you were to rub the rocks on it . like I do

Thanks everyone,

Yes, cassiterite is tin oxide. It has an S.G. of 7, so is much heavier than magnetite, chromite, spinel and sapphires. There is also a crapload of it, up to 100g per pan in a nice deep hole, even more in crevices. This means the sluice can fill right up in no time (couple of shovelfuls). It might even be worth mining in its own right, :lol:

Not a bad idea to keep it if your getting that much, from memory it was going for $10 a kilo last I looked, probably worth more than the gold your getting. It needs to be clean and separated from the other heavies though.

DD

Yeah, the run is a mixture of cassiterite, hercynite spinel, schorl, zircon and the odd sapphire. I can run it longer and get a much cleaner product but lose a proportion of the tin. I'm sure it's worth more than the gold.

M

I made a flywire screen with an old paint tin. Search for bucket sieves.. the flywire is about 1/20 mesh. I used the black aluminium type, cost abot $6 from hardware. Still on the first piece and have ran about 15 - 20 buckets worth of 1/4 or 1/12 through. Yes,I am a bit obsesive with my sieves but the fine gold is there..

I think I will get some today too Tone, I know what Headbut is saying but if I classify from 1/2", then 1/4" and eventually down to the flyscreen, it should be good as all the other large rocks would have been screened out already.

Hmmm, time to get some exercise on the workbench

I've purchased a rare earth magnet with a demagnetizing handle. You use it as a regular magnet, to pick up all the black sand etc and then just pull the lever and it demagnetizes it and the black sand/iron falls off. Easy as Only cost me a few dollars on ebay but it came from the states.

Yeah, but cassiterite is not magnetic. And classifying till the cows come home takes long enough to wonder whether the whole effort is worth my while. Time to move onto a goldfield with less crap?

Not a problem, I'm learning as I go, sometimes you have to weigh up the pros and cons and see if anything is worth the time or satisfaction.
Good luck with the ventures mfdes

Thanks gav,

I'm sure you guys will end up hearing all about it anyway!

Just make a wooden frame or get an old window frame.. I find if your material is wet it is harder to get finer classification done.. have you thought of a barrel classifier or use a tromel with a fine screen fitted..?

Another idea..

Get a sturdy plastic tub.. 30 - 40 litre size..

Get some 1" timber.. house frame type or batten type

Make three frames to go around the top of the tub.

Leave the long side of two of the frames.

Get some security mesh or bread crate type and fly wire
Cut the mesh size of frame and lay crste and fly mesh down. Crate supports the fly wire.
Screw down three sided frame to secure first screen layer.
Cut a piece of half inch mesh to the top three sided frame and place second three sided frame over this.extend the halh inch a bit further out or place openings on opposite sides. Screw this top layer down and you should have a double classifier tray..
Load with gravel and shake it.. you will have plus half inch in one pile,sub half in another and the fines into the tub..

Got this idea looking out my window through the fly wire and security screen...

Cheers Tone

mfdes,
I am not to sure how much gravels you would like to process at a time. I myself use a Banjo box to do my gold and tin prospecting. Don't confuse this with a high banker banjo this is all manually operated. The beauty about the Banjo is that black sands, garnet sands and including cassiterite are your allies not your menace. The Banjo box can catch fine gold uses very little water, highly portable, cheap to make, classifies and washes large volumes of gravel compared to other non motorized equipment. The Banjo box was the favorite tool for the gold and tin miners in North Queensland. Not many people know about the old Banjo box and how it is operated correctly. A mate of mine is nearly 90 years old and he showed me how to operate the banjo correctly. Its easy to make with a sheet of ply wood and the grizzley you can fold up from some tin. I was thinking of taking some pictures of the banjo box and hints on operation and setup. If people are real interested i might do a build along.

Roscoe said:

mfdes,
I am not to sure how much gravels you would like to process at a time. I myself use a Banjo box to do my gold and tin prospecting. Don't confuse this with a high banker banjo this is all manually operated. The beauty about the Banjo is that black sands, garnet sands and including cassiterite are your allies not your menace. The Banjo box can catch fine gold uses very little water, highly portable, cheap to make, classifies and washes large volumes of gravel compared to other non motorized equipment. The Banjo box was the favorite tool for the gold and tin miners in North Queensland. Not many people know about the old Banjo box and how it is operated correctly. A mate of mine is nearly 90 years old and he showed me how to operate the banjo correctly. Its easy to make with a sheet of ply wood and the grizzley you can fold up from some tin. I was thinking of taking some pictures of the banjo box and hints on operation and setup. If people are real interested i might do a build along.

Click to expand...

I would love to see some pictures and tips on how to use it. Some places i go is really hard to get to and when i am on my own i have to make few trips with high banker and all the gear. This sounds like a better/lighter option if by my self specially if it does not need much water. Otherways i have to use AM boss which is hard to set up with little water.
Please start a new tread. I am sure there would be quite a few of us interested.