Gravity Separation & Concentration Methods

Gravity Separation & Concentration Methods 2017-04-04T06:57:23+00:00
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Started by Alex
We are currently setting up an Alluvial Gold Wash Plant - (Hopper bin - Vibrating Feeder - Trommel Scrubber - Sluice Box - Vibrating Screen (2mm) - Falcon Concentrator) We want to process the 75 tons per hour. The clay content is high. And the mat...
Last replied to by Deano
I assume that you have a 300mm wide ring at the bottom of the scrubber section to retain the feed. You would want to have 4 slotted 150 wide lifters on the ring to keep the oversize moving through th...
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Started by ramoah
I have recently come across a small deposit of COLTAN in Africa. I am looking to start a small scale processing plant to produce a concentrate and then separate the tantalite from the Niobium. Can anybody  point me in the right direction. Where can ...
Last replied to by Treve Mildren
In Africa you will only be allowed to upgrade Coltan to a saleable grade using whatever method you choose but most common would be Gravity Concentration.   You would not be allowed to refine Tantal...
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Started by Treve Mildren
What is the realistic feed capacity of a large shaking table ? I know the stated tonnages on the sales data sheets are rather exaggerated so does anyone have any real world numbers? What is the factor which decides that scale up? Logic would sugges...
Last replied to by Treve Mildren
Thank you Deano & Jorge for your comprehensive replies. I will follow up on your advise and read the suggested article by Razaly & Veasy.
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Started by Michael Z. Papadopoulos
What is the minimum size of Chrome ore which is currently concentrated with Fine DMS?  
Last replied to by Michael Z. Papadopoulos
Size as in particle size please.
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171
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Started by biteyaboy
I have knelson concentrate that capture free gold and same concentrate is upgrade into shacking table sometimes ready for Acacia process (Leaching and Electrowinning). Recently i got little bit high copper value of copper. Resuts are 1000 ppm of Au a...
Last replied to by Tesaygo
Hello,  Base from my experience, after you've concentrate the gold even copper ore, try to leach it with water + sulfuric acid. For 8 hours. Sulfuric will dissolve copper. Best regards, tesaygo
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Started by GhanaBob
Hello Colleagues, I want to thank each of you who added great clarity to my previous question of mass vs density measurements. In a similar vein, how can ppm be a meaningful metric compared to g/m3? What does ppm in placer sampling really tell us th...
Last replied to by K@TTU
Concentrations of chemicals in water (solvent) as  written as grams per cubic meter (g/m3 ). This is the same as grams per 1,000 liters =  milligrams per liter (mg/L). Therefore, 1 g/ m 3 = 1 mg/L =...
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Started by GhanaBob
I frequently see Au grade of alluvial soil sample as both g/m3 and g/ton. I thought best practice is using g/m3 for alluvial. My questions: 1) why use g/ton? 2) how convert, say, .30g/m3 to g/ton? What is math? Thanks.
Last commented on by GhanaBob
Bingo! Exactly. Thx
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105
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Started by Sam
This is an old school method I am trying to learn more about. Froth floatation on a shaker table. I don't mean done separately. Does anyone know anything about it? It was mentioned in a set of operating instructions for an RP-4 Shaker Table but not e...
Last replied to by Sam
At his point, I don't see any advantage to it for gold processing on an RP-4. I have seen soda ash and sodium silicate used as flocculants. Water clarity is an issue in recirculating systems. I think ...
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111
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Started by Ausmet71
I am looking into a project that has substantial waste stockpiles expected to have moderate concentrations of Nickel, Copper, Ag and Cobalt. They are mostly interested in the Nickel/Cobalt and more than likely not looking to make final metal/cathode...
Last replied to by David
I have a copy of Extractive Metallurgy of Nickel, Cobalt and Platinum Group Metals By Frank Kenneth Crundwell = the words DMS, HMS, Dense Media or Heavy Media do not appear anywhere in it. Neither d...
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Started by hadi
Dear All, Greetings from Iran and glad to be here among professionals. How to determine metal liberation size prior to jigging of Lead slag with 10% Pb content. Kindly advise if you have any idea.
Last replied to by Alex
I guess your method todetect the metallic particles is fine. Since you already detected a wide range of particle sizes (1 mm and powder) it is maybe not the best to talk about the liberation size, bec...
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Started by Tariq
I ran 6.11% copper oxide on a shaking table optimised to process chromite ore, and got 10.60% in heading, and 4.28 in middling. Copper was milled at 100 plus mesh. There was no control and hence no optimisation. How much say 1% copper ore can be upg...
Last commented on by Treve Mildren
Yes 50g is sufficient but send a little more (100g) in case I need to retest.
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340
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Started by vekian
We have 2 discharge pipes from the cyclone underflow. 1 is a smaller diameter pipe going to gravity/scalping screens which then classify the product. Oversize from these screens report to mill discharge hopper. Undersize reports to gravity concentrat...
Last replied to by David
vekian  I'd be interested in this. Do you have answers to Paul's query?
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Started by Sachin Prakash
Why were copper plates used historically for mercury amalgamation = rather than other metals?  it's always copper.  Thank you
Last replied to by Hauptsturm
Mercury is attracted to copper. The mercury is dispensed down a long copper table, which formed a thin coating of mercury on the whole table. This creates a mercury-wetted copper plate. The gold ore w...
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156
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Started by Alex
We are looking for an efficient Nugget Trap design. Alluvial Gold Wash Plant - 75 tons per hour. Anyone has a proofed efficient design? We found some on internet, but not sure if they are really effective.
Last replied to by Deano
Looking vertically down at a piece of expanded metal sheet the diamond shapes are 3" long by 1.5" wide. The depth of the holes is controlled by the thickness of the metal sheet before treatment, depe...
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264
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Started by terrence
i am using spirals to recover chrome fines size (-1mm) to (+100microns) from ore. l have noticed a high grade and reasonable amount of values in the tailings and after size analysis a majority of these fines are in the range of (-75microns). How can ...
Last commented on by B T Chitapa
Most of the gravity concentration equipment have limited performance on material below -75microns and you also have quality issues if that material has a constitution of more than 20-30% in the feed t...
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179
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Started by Anupam
Can you explain recovery and recovery rates?  Say I am jigging mineral, I get a 60% recovery rate. feed specific gravity is 3.8, final product gravity is 4.2.  If I lower my recovery rate to 50%, what will happen? maintain final specific gravity, b...
Last replied to by Anupam
My thinking was therefore correct. To explain, my boss asked me what if I dropped my recovery. I asked him why, and that if it is to increase quantity, the final product S.G. will certainly drop, (as ...
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Started by explorer64
We sent a substantial amount of quartz gold ore to a mill for processing. After a couple hundred tests on the material an average grade was calculated. After milling for several days the mill says there is way less gold in the ore than what had bee...
Last replied to by David
Funny how Treve here posted photos of a Mozley Multi Gravity Separator to recover gold ... do you see the ball mill parallel? 
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Started by Mr. Nanda kishore
if jigging can process galena ore, which information is necessary e.g mineralogy, feed size, feed, jigging machine type etc. ?
Last replied to by David
Hello Mr. Nanda, unless this is a research project or you are under some serious environmental restrictions, you would not jig galena. Mr. Skinner is correct in saying flotation is the best galena re...
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756
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Started by Latricia Patton
We always come across some customers who want to  concentrate the alluvial gold . And their alluvial gold is with some magnetic mineral,so some magnetic would stay with after gold centrifugal or jig separator . below is the flow offer by some suppl...
Last replied to by Khosana
Hi there, I would suggest that you perform mineralogy studies first before you could rule-out the use of magnet separation.  
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Started by Gabriel
I will buy a centrifugal gravity concentration. What is better? Falcon or Knelson?
Last replied to by Jorge Quintanilla
Many years ago I was involved in a technical comparission between Falcon and Knelson. In that particular case, the winner was Falcon , I don´t know, may be in other mines is different. I have a pers...
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Started by spaceexplorer
We are considering acquiring an iCON-i350 Centrifugal Concentrator ( http://www.iconcentrator.com ); a Falcon SB350 equivalent. However, we got an attractive offer of two units of “Oro Low-G 16” Horizontal Centrifuge Primary Concentrators” (use...
Last replied to by David
Yes, if you have no gold finer than 200 mesh (74um) you might be OK with that low-G machine. Otherwise.... you need high-G for better recovery of fine gold. Can you perform that type for test? Belo...
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Started by Olga
Hello colleagues! Does anybody has an experience with tube densifiers in a dense medium circuit? The picture of densifier is attached.  What are the advantages? Is it possible to set up usual thickening hydrocyclones? What are the differences? Wh...
Last commented on by Olga
Richardh, thank you very much for the reply!
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645
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Started by Wattle01
Hi I'm currently working Placer gold a Quarts Conglomerate, I'm washing in a Trommel, 100 x 15 liter buckets ( soaked over night) in a day 5 days a month.... I have a limited amount of water. I'm wondering if I made a bigger Trommel to wash the 500...
Last replied to by dk
You may use the same existing  system  if required with lower rpm and necessary lifter bars for scrubbing and increase the retention time. The processed water may be taken to 2/3 compartment tanks f...
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859
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Started by NAVEEN VARMA B
Myself mineral processing engineer and am working on flow sheet development.... Am getting problem with maintaining circulating load in spiral concentrator circuit (rougher, scavenger & cleaner) followed by hydro cyclone? As we are giving hydro cyclo...
Last commented on by dk
For balance loading and recovery of desired quality, sample may have to be tested with two stages classification in cyclones, changing the operating variables in the 3 stages for optimum loading of sp...
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585
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Started by anjanisail
Dear All While preparing Flow Sheet for designing of a flow sheet for beneficiation of Hematite Iron Ore, I came across a Problem. I have considered Jig, Spiral Concentrator and WHIMS in my envisaged flow sheet. Based on the available test test resu...
Last replied to by Marshal Dienes
AS YOU MUST KNOW, One of the biggest mistakes in designing a process flowsheet is designing for an "average" ore that will never actually be seen. If Pilot Plant work is done, a range of ores should b...
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Started by Tarun Karakoti
We run a Gekko ILR to leach gravity gold. The problem we have is to estimate the Au recovered using Solution assays & tons from volume measurements. The variation is always approx. -30%. Where are we missing?
Last replied to by Tarun Karakoti
What are the best automatic sample cutters for the solution streams?I think the problem with solution accountability has been identified. It was due to interference with Fe ions with the use of AAS di...
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Started by Jean Rasczak
Could Gravity + Intensive Leach process the Gold in more cost effective manner? Some study in stopping the illegal miners using mercury claimed this opportunity too. Some junior miners samples of Indonesia, showing > 100 ppm Au in the GRG concent...
Last replied to by Hauptsturm
It is good to see you describe the research he has conducted concerning the use of glycine for leaching copper (1 paper) and for leaching gold and silver (2 papers). We look forward to their demonstra...
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Started by Marshal Meru
Within our concessions have abundant tailings (2% Hg and 10 oz Ag/TM), waste from the extraction of mercury from cinnabar, they have potential silver content. What would be the ideal method to benefit them?
Last replied to by Marshal Meru
The raw materials are sandstones with contents of cinnabar, which are the result of the processes of recovery of Hg retorts used by the Spaniards for the 1700. Silver is found as native. So the idea i...
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Started by Helena Russell
How low can your solid tails go?Low grade ores ranging 0.6 - 1.0 g/t Au (silver ignored), Low Cu (25-50 g/t0Gravity- CIL circuit gold processing plant.
Last replied to by Sturmbann
There is no magic number. It depends on the mineralogy of your ore and the efficiency of your process. When I was the plant met at the Tarmoola mill, we went for a week with no measurable gold in the ...
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Started by Amar
Just wondering if there is a better way, environmentally, to reprocess mercury-rich gold tailings other than using a retort! The tailings belong to an old Whole Ore Amalgamation process at a saprolite deposit.
Last replied to by Amar
Gravity Concentrators can only recover about 60-70% of the mercury at best.
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Started by Bob Mathias
When it comes to very fine gold recovery in alluvial operations where throughput volume and continuity are very important, what are the top priorities to consider?How important are say Corey factors, make up of host gravel/sands, gold finesse, clear ...
Last replied to by Bob Mathias
We are indeed doing that. Beyond the knowledge and experience you get by hiring one professional, forum like this may provide different ideas to consider, debate and try in practice. I think starting...
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Started by Carl Jenkins
Anyone experience any significant correlation between feed rate and grade/recovery in GRG concentration test work?If we run 50kg batch, 20 kg batch, 2 kg batch with similar feed rate and other parameters, anyone experience any significant difference ...
Last replied to by Alan Carter
Totally agree with all the above. The nugget effect calls for a larger sample size. Start-up and shutdown effects will bias results so the longer you are at steady state, the better.You need to think ...
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Started by OberstGruppen
There is any specific reaction, to describe the process of amalgamation of gold?
Last replied to by Marshal Dienes
Just straight physical dissolution as sugar dissolves in water. The gold SG is 19.3 and the mercury SG 13.6 if you would take a gold concentrate and assume it is liberated largely from a host like sil...
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Started by Tony Verdeschi
We have a heavy mineral sand project and we would want to use standards samples. Most of our analyses are done by heavy liquid separation to get the Total Heavy Minerals (THM). For now, we use a homogenized bulk sample for our standards but it’s n...
Last replied to by Tony Verdeschi
Thanks for the answers.After having checked the above proposed solutions, I finally checked with the lab in charge of the standards for our Canadian open pit operation and they said that won’t be a ...
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Started by Carmen Ibanz
"Diamond Soaks" for Separating Precious Metals from Precious Stones: Are There Any New and Efficient Methods Better Thank Aqua Regia Then Sieve Shakers? This is a process for recycling by separating precious stones from gold, silver, the platinum gro...
Last replied to by Marshal Dienes
You can use AR with ultrasonic, this will help in agitating impurities so that you have better results separating Au from other metals. Properly alloyed metals should not dissolve and leave behind lar...

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