Grain Harvesting Machine (Combine) as a mobile dry washer

I toyed with some ideas of using the agricultural machinery in gold prospecting for some time. I thought of sharing these ideas, it might be worth a try. The most machine that comes to mind, is the Grain harvester (combine). These machines are used in agricultural sector with great success. One would wonder if he knows how things go under the hood -correct me if I am wrong- why they were never been used (after being modified) as dry washers? Just "harvest" the washes , valleys and collect the yella stuff, instead of hauling dirt with a loader?

Be aware that some concepts while they will work in a controlled environment , with a small scale prototype may change the game when scaled up. This process may reveal certain limitations that are not present or have very limited effects in small scale models.

Here's some resources to illustrate what I am trying to explain:

https://en.wikipedia.org/wiki/Combine_harvester









These pics were taken from this page:

http://www.fao.org/docrep/T1838E/T1838E0P.HTM

I think there is an Aussie bloke who has developed something in line with a Grain harvester concept, take a look at this video clip:

[video=480,360]https://www.youtube.com/watch?v=LFIhU3dIOAM[/video]

And he called it "gold digger" An example of Aussie's ingenuity !

The first ever dry BLOWER was developed by a fella using the grain winnowing principle.

I love this beast..saw it a while ago ..good luck!

G'day , yes, the first dry blower was absolutely just a grain winnowing contraption ! The ole timers tried whatever available on their hands , eventhough some of the gears they used were not designed to recover gold by their original makers.
Thanks Nightjar.

AtomRat said:

I love this beast..saw it a while ago ..good luck!

Click to expand...

Hi, did you see it in person? any info about who made it or where it is located? any clues would certainly be helpful as I am gathering (research material) for one I am planning to build.

Just this vid, sorry mate

I have one over seas, we use it for threshing rice and corn.

Very cool indeed

AtomRat said:

Just this vid, sorry mate

Click to expand...

No worries mate

Look at this page , you can hit Ctrl+F and type "Air separator, dry blower" or select from the top of the page (14.9 Air separator, dry blower)

http://www.fastonline.org/CD3WD_40/CD3WD/APPRTECH/G10TOE/EN/B1125_23.HTM#B1125_23_9

This is not exactly a combine/harvester but has some drawings of a similar concepts of an air classifier for grain.

I hate to be a bummer but when a rock enters a combine it usually does damage, going to need some alterations and reinforcing .

Good point, aussiefarmer Yes, I did write (after being modified) on the first post. The way threshing inside a combine or grain classifier/sorter is a little different than a dryblower . Since the crops are lighter than dirt or for this matter gravel (mullock) and it is inconsistent in shape and surface area, the machine must be modified to accommodate these changes. One variable to be taken into account is the combine moves while doing its harvesting process, while a dryblower must be stationary and no major vibration aside from the vibrating fan (for constant air pressure type or the bellows in case of a puffer style one). The idea behind suggesting a combine/harvester is the mobility of the machine and its own mechanism of self-feeding in contrast of a dryblower which needs a front end loader/backhoe (this is for big commercial operations). What your advice on overcoming the shaking and vibrating that's going through the moving combine? The video link I posted in the first post, shows a stationary dryblower while it is doing it's "digging"
business :lol: hence they named it "gold digger" !

nucopia, thanks for the pictures. That one looks it's doing fine where is it about.

The sieves and straw walkers in a combine are the major cause of vibration or movement, They run so there's a toss and drop motion moving trash to the rear and letting the heavies drop through , The fan mill pumps air up through these helping trash float and also blowing dust and crushed grain out the back. Without the straw walkers the sieves should run fairly balanced but would have to be made of mesh as they are adjustable tin fingers (hundreds of them ) that bend very easily.
I like the concept , thinking out side the box and using the housings and drive system with new insides would start to seem possible.

Thank you very much for the encouragement and backing the concept "I won't say I am the first to think of that concept
anyway "

If you watched carefully the "gold digger's" video in the first post you'll see how they managed to lift and convey the gravel up to the screening area then to the recovery section where there is located a regular dryblower. (I may have missed something, so any corrections here are welcomed as the video quality is not very good).

Yes, those "little fingers" would bend easily with cobbles or small pepples running over them. May be eliminating some of those unsuitable for the job (dryblowing) and replacing them with stronger building material could solve the limitations of the machine?

The vibration could possibbly be mitigated by a kind of suspension mechanism (e.g spring loaders)?

Another video to show the inner working of a combine harvester :

Combine Harvesting Animation (MCS)

[video=480,360]https://www.youtube.com/watch?v=RMU0goBWRjY[/video]

Hi Aussiefarmer. My mate here in SA is in the process of converting an old New Holland TR series into a mobile gold sluice. He has some hair-brained schemes driven by his alternative thinking, but I am sure it could be done by someone of his or your experience. He is talking wet sluice and mercury(trying to talk him out of that).

Here is an update:

A Sudanese man has made a portable dry blower similar in concept to the Aussie's one I mentioned in my first post video "gold digger, australian made" . He tried to fix the issues found in the commonly used dry blowers in Sudan , most of which are local made. They consist of large hopper attached to it several Keene style "dry washer" boxes. Constant air supplied using a big fan powered by a Lister type engine. Although simple to make and operate , these dry blowers suffer from several issues, including immobility of the machine and when wind changes direction the whole operation stops

Here are two videos, first one shows how "traditional" dry blower is run:

They call these large dry blowers "Sieves" :

[video=480,360]https://www.youtube.com/watch?v=8R7u7JL4CUI[/video]

The second video shows the machine I mentioned above, complete mobility but sure there is always places for improvements :

[video=480,360]https://www.youtube.com/watch?v=eAOs4O6Hc4c[/video]