Home sampling finally started

Mine it gets pretty hot too for the few short times I've used it, friction I suppose but they are really only intended as a small sampler.
I can't help but bring back a bucket or 2 of rock samples when I go out and I've got a fair amount to process through the CC now (100ltrs of rock?), I think I need to find a bigger crusher to rip through it and save the CC for small sampling like it was designed for. Once I process these samples I'll concentrate on the area that shows colour, if any do.

Or use a jaw crusher to run your ore down to 10mm and then through the mill. Takes the pressure off the rotors and saves wear. That's what I use.

what size jaw crusher have you got, just did a quick google search and they all seem big industrial units, do they have smaller hobby units available?

I hadn't even started putting anything through it, when it burnt me. switched it on to start and within seconds the grinder was too hot to hold. Crusher in my opinion is too heavy for grinder & forcing grinder to work far hard than it's designed use. It is the grinder getting too hot not the crusher, but the crusher also has it problems.

I had a couple of problems at the start, the vibration was bad, turns out it needs to "bed in" for a minute or so, the wing nuts kept spinning off as soon as I fired it up, Ryan sent out some rubber washers to put behind them and it's stopped that issue, I had to tighten the bolts that hold the chain to the arms on inside the crusher a couple of times and also re-align the crusher unit a fraction where the bearing sits, done by sitting the crusher unit in a vice and getting the shaft as close to 90deg as possible, the shaft and baring pivot in the backing plate.
After these minor adjustments and bedding in time my unit is doing it's job well although I do 2 scoops at a time, stop the unit to shake out the dust and go again, yes the grinder does get pretty hot and hopefully this won't affect the longevity of the grinder and only time will tell though.
Hopefully some of that helped in some way but hopefully Ryan will get back to you to sort out your issues with it.

Personally I don't regret buying one, it does what I wanted it to do and I understand and accept there are some issues with getting it running correctly and I think they are only teething issues, I really like the concept and portability of it, if the grinder burns out anytime soon then I would adapt the crusher to my big ol' Makita and hopefully continue to keep the samples going.
For me it's a winner but yes agree I was disappointed at first, but as I said I've only done a few samples and time will tell on how the unit stands up. Used as a "small sampler" I can't see why it shouldn't last but if your grinder is getting so hot so quick then sounds like there's an issue, mine gets hot but only when it's doing a fair bit of work, I ware riggers gloves simply because of the thought of the moving parts in it, maybe mine does get really hot but the gloves hide it a bit.

It got that hot grinder was smoking after only about 10 seconds of run time. I will not say any more until I get his response.

oh boy, good luck then dave.

Hi, I am a newbie on this forum & checking out your pictures of the Gold Vein and ore you have there.
I am an Ozi in Japan & 48 hours ago in a known Gold location here in Japan found a Big Quartz Goolie that come out of a Gold bearing stream where generally plenty of small flakes of gold are found .
This Big Goolie has been Spat out of the stream by Typhoon recently outside on a rock pile in the sand bar, when found exterior was Dry, interior is heavily saturated with water.
Found small around the exterior & loads of Oxidization evident in the seams or cracks and flecks of gold , I Broke of a Big chunk yesterday in the stream & bought it home.
There is pyrite & mica visible & I am Seeing what appears to be Gold !.

Reading your posts it appears you have considerable knowledge re Gold ore Gold veins any chance you could take a look at some of my pictures on photo bucket lucashardy22 & let me know your thoughts re this specimen Please.

Cheers

Lucas

Throw them up here Lucas,..you have enough posts now.

ProspectorPete my jaw crusher is 8" by 6" single toggle. Powered by 10hp petrol engine through a 6:1 reduction box to run at 240rpm. Mine was made years ago in Bendigo and has replaceable wear plates etc. I use this, then my own mill which I have used for nearly 30 years. My ore comes out finer than battery sand. You can buy small jaw crushers from China and I have heard they go o.k. 8" by 6" can be trailer mounted with the mill also. I have seen many people just using hammer mills to crush ore but if you put anything through bigger than a marble you will get excessive wear. They are alright for small batches but if you are doing a lot of quartz use a jaw crusher, reduce the ore to 10mm then through the mill. Less wear, less work on motors, and you will get a better end product.

Thanks for that Puddler Bill, great info there and I'll definitely be looking into it if I continue bringing samples home, crushing through the big dolly pot is hard yakka and the neighbours keep asking what all the banging sound is.

Happy to help..

dave14110 said:

It got that hot grinder was smoking after only about 10 seconds of run time. I will not say any more until I get his response.

Click to expand...

Hey Dave, what was the verdict?
I finally got around to start processing again yesterday and after about 5 mins (6 half scoops x two at a time with shutting off/empty between scoops) the grinder slowed quickly and smoke coming from the bearing, shut it off and will look at it tonight.
I've only processed about 1 litre in total on this CC............hmm

Hey pete best to only pulse the grinder with each scoop also the smoke will be due to tye bearings not being square i would say. The piece that fixes the grinder in plxae is far too nimble for its purpose ive found it twists out of place. An easy test is square ot off and hold in a bench vice. Hope you get ut sorted....

Thanks mate, I'll have to get my vice setup very soon and re-align the shaft.
I only switch the grinder on, put 2 x half scoops in and switch off and empty after 10 seconds, hoping it's not burnt out but will set it up in the vice and try a mod or two, otherwise I'm thinking of biting the bullet and get an Armstrong GRB 777 mini so I can process my many buckets quicker.

Can you convert from a grinder to a 1/2 hp 240v electric motor? . The load on a mill when crushing is greater than you may think. Also the size of the rock is a factor. I would not put anything more than 10 mm through a small mill. If you do, the hammers will wear excessively, and the load on an electric grinder will cook it. I use a belt drive on my 5hp mill and the belts are not too tight.
The problem I see with a grinder powered mill is the load is directly on the motor.
In my mill if there is excessive load, the belt will slip a little.
If I put bigger rock in, say 25-30 mmm, I can destroy a set of hammers in a day. !0mm or less and they last for weeks. It comes down to a simple fact. Always buy the best equipment you can and make sure it is suitable for what you want to do.
Now another fact here is the type of hammers in the mill.
I use and have always used knife edge hammers. The current trend towards a hammer mill with a hard bar across the paddles will generate more drag inside the chamber which in turn puts more load on the engine, creating heat and thus burning out electric motors prematurely.
The other critical point in hammer mill design is the rotor speed. From over 30 years of owning a mill, and talking with others who use them I suggest that the optimum diameter for a mill for small scale mining, is 9" diameter. The tip speed of the rotor should be close to 3400 feet per second, which is about the same velocity as a lawn mower at full revs. The higher speed combined with the knife edge rotor design, impacts the stone, sending it spinning around the chamber where it is hit time and time again until it is fine enough to pass through the screen and on to the next stage.
If larger stone is put into the chamber the knife edge rotor design will impact the stone with less loss of speed that a paddle type rotor set up. An electric motor, constantly being put under load will get very hot very quickly and won't last long at all.
Hope this helps.

Are you talking about this type of setup Puddler Bill?


The rock crusher I built smacks the rocks up pretty well. I run a 20L bucket of rock through it and when I'm panning out the cons I use a rare earth magnet to pick up all the little bits of steel that have been busted off during the crushing. I will be hard facing the bars to minimise this in the future. My crusher runs at around 750rpm or there abouts and only stalls if I whack a big bit of quartz down the tube because i've been lazy :|

MJB that's exactly what I am talking about. Knife edge and hard faced. What also helps is to make the rotor reversible, so that when the hammers get worn down too much on the leading edge, turn it around and use it in reverse. The only problem is that when the rotors are worn out its a whole new shaft etc. I am working on replaceable hammers that bolt in. Will post a pic when its done.

I'm looking forward to seeing the pic's Bill.
The Compact Crusher uses 2 bars crossed with 2 links of hardened chain on each bar and it does a good job of crushing small samples.
I'm only putting in marble size at the biggest and the process is - switch it on, put 2 x half scoops (2 table spoons) in for 10 seconds then switch off, shake dust out and start again, great when it works but hard to hold the grinder down, I've got it on a thick rubber mat but it still wants to go walkabout, going to look at cradle mounting it somehow.
I think the problem I'm having is what G0lddigg@ is saying and it makes sense to, I recall the handle on the grinder coming loose the 3 times I switched it on yesterday which is a pain in the butt, I tightened it on the fly each time but it would have thrown the bearing right angle out hence creating friction.
I'll realign it tonight and try putting an O ring on the handle thread or something to make it stay in place.
My main concern is the grinder slowed quickly to a near stop when this happened and I'm just hoping it hasn't burnt it out, if it has then I'll try and engineer a motor setup to it, my shed/workshop still has no power or work benches so everything is stacked up on the floor for now making it hard to do anything in there but I've got a couple of benches coming in the next couple of weeks which will make life easier to work on things.

Have always been a fan of Vertical Shaft Impact (VSI) for gold ore.

The motor is only utilized purely for velocity only, and the intended 'crushing' achieved via the stones impact against the impact wall liner.

To me it makes sense to use pure velocity and impact 'shatter' taking advantage of the natural fissures in metamorphic stone. The harder the stone the better, so these types of crushers love quartz.
Major advantage being way less stress on the motor as it is not utilized in driving 'metal upon stone' in order to crush. The only wear involved are the liners on the impact wall.

It also takes advantage of the principle of 'stone upon stone' meaning the stone flying around at great velocity collide with each other thereby enhancing the effect and not wearing metal.

The end result tends to give a more 'cubical' design to the crushed product allowing for easier classification with less runs.

Might be a design to consider Pete. Keene do a beautiful portable sampling version!

https://www.reedsprospecting.com.au/shop/detail/keene-rock-crusher/

Regards

Edit: What has happened to Ryan27? Anyone know? Haven't seen any input for a while.