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Rotary Pan (33 replies and 1 comment)
I could get you Rotary Pan. Please advise on the size you require for Alluvial Gravel you can 'Feed as Follows at -32mm - 10' Foot Pan = 25 Tons per Hour, 14' Foot Pan = 45 Tons per Hour, 16' Foot Pan = 65 Tons per Hour and a 18' Foot Pan = 80 Tons per Hour
I need a 10' or 14' Foot Pan. Don't want to import from SA though, just want to test some land I am working on in Paraguay just across the border from Brazil. So would like to keep costs down till I have certainty of diamonds in the ground if that makes any sense.
However, it would be interesting to know what it will cost to deliver a 14' Foot to Paraguay.
A 10' Foot Pan would go for around $30,000 and a 14' Foot Pan would go for around $35,000. Bearing in mind there are many Clowns out there who think they can build a Pan, there are only Two Companies that have perfected this and they are Barkly Engineering and Oranje Vaal Engineering, both located in Barkly West. As far as the exporting and transportation costs would be, I have no Idea. The Prices indicated are a Good Guide for Used Equipment.
By the sounds of it, this will be a Greenfield’s project and surely you'll be looking to keep your costs as low as possible whilst not having the uncertainty of small stone loss from a pan. We have an option for a small combined scrubber/classier, Pleitz jig and 2" water pump unit that will treat ~1 TPH for about $70,000 which would be ex-SA. As an alternative just buy and import the jig for ~$35,000, and use a cement mixer as a scrubber and manually screen out the gravel to feed the jig, obviously slightly more manual but certainly keeping the costs down.
There was a 100 TPH pre-treatment plant, 30 TPH DMS and Flow Sort final recovery plant for sail in Brazil and that may still be available but obviously you'll need to prove the resource first.
Thank you for your advice and different available options.
I found somebody in Brazil who builds 8' Foot Pans and at the moment it looks like the quickest and less complicated route for me. Just wish me luck as I am going in unchartered waters to an area with no Garimpeiros or prospecting history in Paraguay. Obviously I have my reasons for going there. Any advice on Paraguay / border Brazil area would be appreciated.
Rotary pans will recover diamonds in Brazil, and any other part of the world, as long as they are correctly calibrated and operated. The challenge is to maintain the feed rate / density of the medium at correct operating stringencies.
As well as it probably being easier to buy a jig concentrating system in Brazil, it will also be easier to find people who have experience of calibrating and operating jigs as opposed to rotary pans. I would also imagine that there may be more options of buying second-hand jigs rather than pans in Brazil. Whichever way you go, you will need to have your front end preparation set up – as Ivor indicates.
Moving into “uncharted waters” may also mean the need to test sample a widespread selection of sites. This being the case you may be best off with modular units for pre-treatment and moving pre-treated material to a centralised concentrating facility; otherwise moving the lot.
I have been in the digging game many years and have own and operated my own plant (14 & 16 vt pan operation) In my opinion the best way to explore is to have a bushman's jig on a trailer that can be pulled behind a 4 x 4. This setup will enable you to quickly go from one spot to the other. When you recover diamonds you might want to go over to bulk exploration.
This discussion is quite interesting - more skilled people is joining - sum of experiences always bring good results.
At year 2001/2002 I've built here in Coromandel a huge plant with 4 pans /13feet - assembled in two sets side by side, one above the other - everything on the long truck platform (12 m long) - my aims where finding an innovative secure process of concentration (cheap/easy operation) and economic with water process.
I say if somebody do not know where to go, any place is a good one - I was in a good one at the moment, then you friends imagine the initial disaster.
In Brazil we who understand (a little feasible) about rotary’s are rare - and deep knowledge, only Carlos Veloso. I've had good experience with in Angola / Congo and SA with these pans (long time ago) and contracted a 'genius mechanic' projects to put all my needs in order to build/assemble. What challenge...how many money/ time lost: but (according to Thomas Edison) experience/geniality is this: 99% of work/necessity and 1% of luck. Geniality is blow that sometimes occur...
The mechanical project was genial - three interpenetrated self-sustained structures, one of them rotating - but to learn how to regulate it was another war.
I flight to SA again to 'see with hands' all my doubts, and after months of tests and annotations, and immense angers I finally succeed making that 'mammoth roaring like a lamb' but biting like a leopard always.
I made unthinkable sort of tests - since virgin gravel to rewashed ones, classified gravel to mixed ones, separated in two sizes, 3 sizes, with clay/sand and without it. Each kind of gravel gives special answer.
I made my own 'operational book' - what is good and what is dream -I learned with blood drops what to do when (if) necessary.
This year our company is starting a long process of washing gravel (after 8 years of hard studies and patience with governors) - our operational modules will use rotaries - one up to 25 tons /hour and others up to 200 tons /hour.
I certainly never will build another adventure like this above related - Carlos will help me always but he builds only 8 feet ones (my first with two pans)
The others certainly will buy at SA - but (always but) - how to transport these pans from port to here (1400 km)? The transport price will surpass the equipment one.
My appreciation for all your good advice and I will certainly follow some of your suggestions when the time comes. I am still waiting for my license so can't do a lot at the moment.
I have been mining for many years in SA with 6 Feet, 8 Feet, 10 Feet, 12 Feet, double 14 Feet and single 16 Feet pans. I can most probably built one myself if I could find a good boilermaker to do the cutting and welding. Hopefully I can visit your site next time when I come around and I am more than willing to give you some operational / design advice on your plant - sounds like you have some uncertainties about your pans.
I will contact Carlos in due time to enquire about his 8 feet pans and prices.
I will also need a Diggers dream / bushman jig definitely.
Considering the nature of your work - investigative phase - it’s not a good idea you expend lot of funds in machines - strategical and cheaper, you use one or two pans (of Carlos) plus other equipment he can supply you (if necessary) and send it to PY for work - not exporting.
If positive or negative, you will send it back to Brazil and sell it here (recover back partially your investment - minimize costs).
If you succeed and go away with professional mining, you might built big ones if will follow with the same processing method (I don't believe you'll do) the difference between adventure and venture is the strategical planning
Building normal pans are not difficult - but (my advice) make the detailed mechanical project first - you can request several persons (or only one - it’s up to you) to manufacture pieces in Brazil (you will not find it in PY) and transport nearest possible everything.
Build the structure mainframe nearest possible or do what I did! The pans I made 'half-moon' and joined/welded/ finalized everything at field (never more for me, be sure).
I didn't talk before was the sort of 'different ' tests/ project alterations I made - it can be revolutionary and I plan use these alternatives here.
One or two 8 feet pans plus accessories - one truck only - from here to there 1400 km (+/-) - you do what have to be done and recover partially your investment.
Let heavy strategies etc. etc. after having everything done - with cash at wallet
I really trust you're going to succeed there - that is a good place, despite troubles.
Best to get rid of the sand by firstly feeding the gravels into a scrubber then a dewater screen and then into your Pan plant. It’s called a closed circuit operation whereby your porrel is used continuously in your plant. Sand is a problem in a pan plant and not a friend of diamonds especially smaller stones.
All plants I assembled, sand and clay are mortal sins - because this I hate jigs.
A scrubber and a dewatering screen are good for breaking up and removing clays and silts. To get rid of sand (and assuming little or no clay) I would recommend a trommel with high pressure water jets. If you do have a high clay content, then scrubber to trommel would be my choice.
Depending on your bottom-size cut off for diamond recovery, the trommel would remove most of your sand. Water / ore ratio and rate of feed can be critical in pans in provoking abrupt changes in the density of the puddle and invoking porrel additions to compensate. This is not simply resolved by a closed system circuit
I still confess to a preference for jigs – maybe due to better familiarity and simpler operation. Silt / clay removal and gravel constituent free up is essential as is the treatment of different size fractions and the stroke and frequency for concentrating each size range. They can work exceptionally well. Ask the garimpeiros (diggers) because their nest of screens and the concentrating methods that they employ to recover diamonds are essentially nothing more / nothing less than hand jigging!
If you have a low supply of water and need to re-circulate, then pans can be a more appropriate concentrating option.
I agree that each gravel needs to be assessed for its peculiarities and the treatment method and modules adapted accordingly.
I would also consider putting the screened out fines through a gold recovery system.
For artisanal alluvial hand mining try the turbopan, http://www.turbopan.com. Diamond SG of 3.5 means it will separate gravimetrically from quartz, feldspar and clay.
Water does not stick to a diamonds. When clay is present the chance in losing a diamond is real; without a scrubber.
About 90% of Diamonds are Non Wetable, the other 10% will run over Grease Tables as if the Grease was not even present. Diamond has an SG of 3.15 and not 3.5.
I see we all believe/observe the same things. When I started in gravimetry, (40 years ago) I've tried new conceptions in it - Till today I see most part of persons thinking in a 'frozen intelectual world).
Studying the conceptions I noted that all formulas, calculations, infers and dedutions considered not what really occur in nature but the specific properties without correlation with the 'environment' and the properties of other components (and its variations).
I'll try to be more clear:
SG of diamond is 3,52 (yes or not?) - Correct answer: it depends if we consider one ' crystal cell' of diamond or a crystal; a diamond cell 'weights' 3,52 but only it... One crystal depends upon of shape, clarity, fractures, color elements, geminations everything.
Other considerations: diamond is carbon: C (+4 or -4) - this special characteristic in diamond changes everything so it is a bipolar crystal.
Diamond do not wet: true or false? Depends... specially inside a caolinic/ilitte clay environment - so that in sediments, 'environment is positive polarity - diamond assumes the inverse naturally. Worst: diamond wet more we imagine - its changeable polarity induces great part of crystals to attract/adsorbed (not absorbed) an electrical skin of the cited clays (electrical effect of the polarity) - diamond don’t wet but skin of clay is wet so it absorbs water
Other thing - is diamond light or heavy mineral? Depends... it is the lighter of heavies or heaviest of lighter - it ill assume always the behavior contrary of our need. And its SG becomes dependent of external factors like suspension clays, greases, etc. etc. I feel (only feeling) that the dynamic density of diamond might oscillate from 0,8 <Dd<4,0 - depending upon the environment!
There are directly 13 variables influencing the gravimetric process, but we quickly find some 2 out 3 more... I challenge all: try to gain a gamble against one or two variables: face or crown with a coin - and get your answers.
And in the defense of the jigs - if we consider all the above data as true, jigs recovers diamonds because 'God wants'. If you select the gravel it doesn't work, if you add fine material, you increase the 'expulsion rate' of machine - and it is not adjustable.
In some instances, I use/recommend jigs, sometimes with other devices and in controlled environment. In diamonds gravimetry nothing is ultimate solution - we must study each situation to decide - subject to big mistakes.
I made already thousands of tests, spent more (mine) money I would like and generate more trash of iron than possible - looking for solutions.
I found quite good solutions to improve all methods:
first and ore important - feeding any process by base - if I put diamond at bottom final end point - the question is expulsing the rest; inversely feeding by top I have 13 or more variables fighting against me.
Never use gravimetric feeding - to avoid the last item - I'm studying now using peristaltic pumps like concrete ones (will visit Weir Co. this week) to see feasibility and prices.
Second: never believe in final solution - the most effective equipment is the simplest possibe but must increase the chances, so that I develop a 'mixing of everything'. I am in phase of mechanical project - hopefully till end of year I'll test!
Third - use one water to wash/disintegrate water - eliminate clays as perfectly as possible and other water (treated with iron chlorine) to concentration.
Basically I tried to think tridimensional and am mixing jigs to pans to several other (mine) inventions. If positive, I'll put this project free for all interested people!
Question for those who knows Brazil diamonds? You will see in my little presentation on my Profile about South America that we recovered this round "Balast" and also PINK micro diamonds. However I was told by a source that this "Pink" diamonds are very common in Brazil. Now the question is: Are they really that common or do I have a special deposit / area, which I obviously do hope to believe! That is one of my main reasons for going there.
You're right - as I told you already long time ago
Basically APIP - Alto Paranaiba Igneous Province (Coromandel, town I live is in the middle) is the most important producer of pinks - the biggest already found in world .
While the world produces rare pinks and small crystals, we easily produce big ones every year - by semi artisanal.
APIP is responsible for the biggest reds and pinks of history.
A (not yet understood) geological structuring and partitioning give to us this position.
You might not know it but it was because of your information with our previous discussion (2013) that I was convinced to actually go to PY and checked it out. I do think you have a lot of knowledge in your field and locality. Obviously I did my own study as well and some due diligence and it looks like it is going to pay-off at the moment.
Hopefully I can come around one day and "Thank" you. I read about a 79ct Pink found by Gilmar Campos at Patos de Minas in 1999. Do you know about this stone?
PY target is very interesting - ought to be checked - when you install sometimes I'll visit you so I'm interested in that geology long time.
Geology is my real interest - diamonds are only consequences (good ones). I've crossed the globe several times to see a single outcrop - diamonds and metals: my passion!
Yesterday I had a coffee with Gilmar and brother, in Patos (nearby Coromandel)
I had that stone in hands several times - it was a real star. At same days, I saw another from Paranaiba River, with 315 ct - Fl / D color - another 'touch of God' ; in 2004 I saw another pink of 116 Fl/ intense pink probably vivid that was a 'bless of God and the touch of Angels'.
Few month ago I saw other with 8 ct red/pinkish (impossible determine in rough) and other more, last February, with 22ct - intense vivid pink - flawless too.
Among several others last 40 years - thanks God a lot for the chances.
Incredible, you are blessed to have seen so many BIG Pinks in your life time. I recovered only one 3ct pink in my mining career. If they refuse my license in PY I might join you in Brazil ;-).
Rotary Pans yes I have used them. Maybe a couple hundred thousand
tonnes of diamondiferous material. I have worn out many of them. The best
the smaller pans eight foot and ten foot. I found them very reliable. And the
most important part they will work anywhere. You have to remember that these
are really just heavy media plants and you need good feel for the material
going in the front end. . Don't know what you are using to concentrate with
but a good option is a multiple size screen jig.
Any help is a good help when exchanging experiences. I totally agreed to you about sizes of pans - I built already with 13 feet - and considered to make it smaller.
I'm planning develop another search with them to set up operational limits - it’s a complicate algorithm with 14 variables - must invert the operational procedures to make negative variables work positively.
What are your feelings about operational details like:
* work without slurry pulp - with clean treated water?
* Selection of gravels - what about intervals sizes?
My works I tested below of 2 " - observed that bigger than 3/4" (18 mm) dropping diamonds become difficult - and bigger diameters better must be the selection gravel
For fine diameters - small than 6 mm - the selection is not important but absence of clay/sands are always good idea. Otherwise, I fell (only feeling) that better selection / better recovering (according to gravimetry theories). I want to test an idea I had some years ago - using vibrations (high frequency) to increase dropping. Tests I made showed positive but the project was not adequate - need to put pan over springs and alternate real thickness of iron (avoid cracking/ fracture it). I am in phase of mechanical design. Any help/ any critics/ any experiences area welcome. For now - my projects here will follow on 'normal pan process' but searching for improvements is a must (I see) and I need something more to use spare time.
Don't get too worked up about the particulars. The Rotary pan is a simple machine.
I will describe how they work the best. First you need about 50 to a hundred yards of material not wet semi dry. You use your front end loader I use a 930 or a 966 to feed your hopper this feeds a conveyor, again the reason for being semi dry. Now this dumps into
your Trommel Scrubber hole size 1 3/4. The under size then dumps down into the feeder hopper wet from the spray bars.And the oversize is ejected. Now the bucket wheel picks up the material 1 cubic foot at a time and feeds the wheel. The outside stirring tang is traveling at about 4 second to 3 seconds for every 360 degrees. Important thing to remember is that this plant works as a heavy media plant. You need to keep the specific gravity of the slurry within range for the plant to work, I Guarantee that if the plant is set up right you will catch Ilmenite in the slurry waste but no Diamonds. The plant will not work with washed gravel. Have fun I will look up some photos for you.
Thanks to friends who posted comments referring to me on this topic. To handle both primary and secondary sources is always advisable to have a proper pre-treatment, preferably a scrubber / trommel with a gentle spiral retardant and with an equipment rotation reverser, running at about 45-50% of the critical speed so there is no impact and therefore there is no cleavage of the diamonds, get a good disaggregation and also separate the oversize; however I would not recommend to fractionate the grain sizes. In my opinion the 8 feet Rotary Pan is the most practical measure to transport because it does not exceed the conventional width of a normal truck, not requiring protective escort services in transportation and as in operation there is usually a front loader that loads and unloads easily this machine. The efficiency of this size has been very satisfactory and in my opinion, instead of build one with a larger diameter y will opt for two units feeding with a bypass. The main details to obtain a good recovery using a Rotary Pan is a perfect spiral, an appropriate angle of the knives to treat the desired ore, speed etc., This however, the most critical point is the adjustment between the centrifugal and centripetal forces that if are not within the ideal parameters can result even to the total loss of the production. I hope this information will help to clarify some doubts.
The issue to which I will refer concerns about comments posted here on jigs.
Over more than 40 years in the area of concentration I had some experiences that led me to the following conclusions: Among the various types of jigs available in Brazil the most reliable to me is the Pan America, however none is very efficient working with a select size separation as we will have large interstitial spaces that are harmful to the system of suction and impulsion generated by the diaphragm and in these cases the operator erroneously refers to increasing the amplitude. Another very important point and that is usually not given due importance is the water pressure in the cabinet that must be controlled in order to feel strong suction putting our hands on the surface. To recovery fine diamonds, feed must be, for example considering the undersize 1 mm or 1.5 mm the size gravel must be selected >1mm and a maximum 6 <12 and so forth. The adjustment of a jig follows the standard "for smaller particle sizes smaller amplitude and a higher frequency and for larger particle sizes greater amplitude and lower frequency. Another very important point is the feed rate that must be at most 4t per square meter of jig area. An effective pre-treatment is always necessary to avoid clay balls and in this case the Scrubber / Trommel running at 45/50% of critical speed with a smooth spiral working as a retarding system and a reverser rotation for periodic discharge of heavy minerals provides good efficiency.
Your considerations about jigs are perfect. Even about rotaries - but - I always do not agree it is a 'final solution' like they are now.
I do not disagree with you and other (I'm learning with you all) - but I grant it can (and ought to be) improved by new ideas and technologies.
There are among 13 (negative) variables involved in gravimetric process - all of them must be analyzed step by step - at the process to plan changes / tests and pursue success by tests/ observation. The price of pioneering spirit and necessity of new yielding applied to old (genial) ideas is very high and evolution ought to follow its way - without this, people like us never might born and without this pioneering spirit we humans would be using stone hammers...
All tests I made last 14 years show its possible/feasible
In science/research one way is ' we believe it’s possible', other way is (after testing primarily) is 'we have enough data to proof its possible'.
It all starts with a particle size distribution. Once that is established we can start talking about equipment. I like jigs, but only as a very rough primary concentrator. Certainly more forgiving than a rotary diamond pan. You may also want to look at the Bourevestnic Polus M X-ray machine for first round diamond prospecting. I saw it in action at the last Mining Indaba in Cape Town and walked away very impressed
I would like to congratulate all members of this group for the interest and opinions posted here, especially on the Rotary Pan. For humans was always easier to condemn a machine to accept possible operating errors. The Rotary Pan was a victim of this behavior in several locations. For several years I have dedicated myself to the study of operation and efficiency of various equipment used in the evaluation and exploration of diamonds and concluded that this is a device that if well operated, offers us great efficiency. In order to assist those in need I thought it could be useful to make some notes that are in fact my simply opinions but I hope to be constructive and therefore can help. The points and conclusions that I will address here are all result of personal lived experience. The Rotary Pan is certainly an efficient equipment, but its simple appearance deceives as it has several and important factors that should be considered. Several variants must be observed in order to obtain satisfactory results as for example perfect spiral and angle of blades, the speed that varies according to the product to be treated, pulp density and mainly the control of centripetal and centrifugal forces. In my opinion this is the most important factor and must be observed by a pro. Another important point is the density of the pulp, I prefer to work with density of 1.15 / 1.20. I've worked in areas where 1.40 resulted in ore movement following the movement of the blades, eliminating the centrifugal effect. A member says above that it can be found in the tailings some Ilmenites but never diamonds, sorry, I do not agree, in view of the density difference between these two minerals (diamond 3.52 and minimum ilmenite 4.5) In my tests of efficiency I never found Ilmenites or even pyrope garnets near the exit of the tailings of these machines. There is also a comment above about the hydrophobicity of the diamond, here I point out that there are actually diamonds that do not stick to the DB collector (grease), but are rare, according to my knowledge there are only two areas in two different countries where this happens, one is the in Jequitinhonha Valley in Brazil and this phenomenon is due to a micro film called "coating" that surrounds the diamond and the only thing known that eliminates this film is the contact with our fingers. If we touch the diamond with this property with our fingers and put back this diamond stick immediately in the grease. I hope I have contributed positively to this topic and comments are always welcome.
Hi there, I just started prospecting in Lesotho using a 10ft pan. Does anyone have any videos they could share with me? Thank you,
Rob Riggir has kindly sent me some info already. Apologies my email address is email@example.com
I need a Rotary Pan (De Beers Pan) for diamond recovery. Used or new will do.
I was told before that the Rotary pan does not work in Brazil, apparently they prefer Jigs in Brazil. Can anybody comment on this as to why, maybe? I am very familiar with the workings and efficiency of the Rotary Pan, therefore would like to know why it is unable, according to some, to recovers diamonds in Brazil?