Hello all. I'm hoping to pick some smart brains for a bit. Anybody have any experience pumping gravel? Long rambling explanation here. I operate a placer gold mine. Similar to what is shown on gold rush just scaled down to a 2 man operation. (Without the big TV $$$...) The best, really the only way to productivity mine my site is to have the wash plant set up on a high pad dumping fine tailings into old mined out pits. That involves hauling pay to the plant. And having to move half of that (coarse rock) around to finish backfilling. I am exploring setting up my wash plant on a excavator chassis and feeding it directly in the pit. Mounting a 50' conveyor for coarse rock. Swiveling the house should fan out the tailings enough to be out of the way. And let me keep it close to the hoe at the face. The catch is trying to get rid of fine tailings. Looking at options. I'd like to dump the sluice boxes into a containment box and pump them out of the pit. Be roughly 1,200 ish gallons of water a minute carrying 40-50 yards of 1/2" minus slurry per hour. Anybody have real world experience around gravel pumps? I'm trying to figure out how to make this problem work. The material coming off the sluices will vary by both the amount of gravel and the water volume itself will likely vary slightly as well. The gravel pump taking it away has to be able to handle the highest flow but yet not run dry enough to cavitate and quit pumping on the flip side. I'm figuring an electric motor and vfd but not sure in the real life how this will work. Any first hand experience?? Right now we spend half the time digging and hauling and the other half the time sluicing. If I can figure this out it would double our production and cut out the hauling completely. So it would be well worth it even if it's a constant fight. Thanks.
No experience with gravel pumps but interested to see if someone on here has input/experience. Would some type of sand screw be helpful? How high of head lift to get the fines/water out of the pit area? I do know that fine tailings build up pretty fast. We just dredge out our settling ponds with an excavator, set aside the wet sand and then use to backfill pits/reclamation later. We usually do progressive reclamation; so as the pit advances upstream we backfill and reclaim as we go. Our small double shaker deck plant is pretty easily moved... I also spend about half the day sluicing with the remainder digging pay, moving coarse tailings, keeping settling ponds clean, fueling/greasing/maintenance....
I've worked with plenty of trash pumps for dewatering coal mine pits. It doesn't take many solids before the slurry is too heavy to pump. The interior of the pump case and the impeller gets pretty sloppy real quick and then the amount of solids reduces the head height that can be pumped. If you are pumping level or down hill it might work. If we had that many solids to move we used conveyors.
Good to find another placer miner here! I'm in the Yukon mining a relatively large, lowish grade fan deposit at the base of a canyon. Overburden ranges from hardly anything nearest the creek to 16' of clay the furthest out. South facing so only a couple feet of permafrost on top. Just below the organics is a coarse rock layer 6-12 feet that is my main pay. Below that is a dogs breakfast of sand and pea gravel with various thin seams of coarser rock/clay. I've gone down 40+ feet chasing clay layers but it's spotty. Bedrock is well over a hundred feet and unreachable. I'd love to run a floating wash plant like the Kiwi's do. I don't think you could beat the efficiency with a 2 man operation. Problem is I can't hold a pond with all the sand under me. My tailings ponds will drain to ground until they get silted off and filled with fine tailings. The idea of putting the wash plant on an excavator chassis would be to basically emulate a floating wash plant but on dry ground. Convey coarse rock off the end and Pump the tailings over the bank on top the coarse rock on the other end of a cut. Be basically backfilling continuously as we mine. Max vertical lift of maybe 20'to 30'. 400' max pipeline length. Deeper than that a guy could cheat a bit and push to the hoe with a cat and bench everything down enough to reach the bottom. It just bugs me the whole time hauling dirt around when all we are doing is washing it. Gotta be a better way!
I would look at pumping clean water into an eductor.
What's a eductor?
I have worked on lots of different 6 inch pumps and rest assured that the impellers do not last too long if there is too much fines or gravel. My suggestion is to watch closely what techniques the biggest use and try to do on small scale. Once you start using bigger hoses and stuff it quickly becomes a situation where you need more people to move stuff. I have watched quite a few of "Yukon Ali's" videos and hers is more yardage per hour than you are processing but same idea. Bigger gear will mean bigger repairs. Simon C
The Norton Sound placer bois like their Eddy Pumps for moving sand and gravel long distances.
We could ask Emily.
I know the 3rd world countries mostly use slurry pumps with hand labor throwing the large rocks out of the way. I just don't know the real world wear on something like this. Say an impeller and liners every 50 hours or 500 hours??? The devil is always in the details.
We are mostly third world in Western Ak. That’s a good question. I’ll ask what the maintenance is like on them. Welcome to the HEF. We look forward to hearing about your mining adventures.
What I saw on that program were eductors. We had them on ships for emergency pumps to dewater spaces, tanks and voids. Basically it is a pipe the is sucking on one end and discharge on the other. The water pump is hooked into the middle of the pipe into a jet mounted inside. The high pressure jet creates a suction. The problem I think is they don’t pump up hill much and you need a whole lot of water.
So similar to a well jet pump. The pump forces water down the well in order to force more water up. The pressure through the valve down the well is like a venturi and creats more suction than the pump itself. Difference is the mud doesn't go through the pump
Futuro - Single Piston Pump To evacuate free stall manure containing limited amount of bedding. www.gea.com This is designed for manure with sand, do you think this would work?
Too bad you couldn't find an old concrete pump
Similar concept to a gold suction dredge (Like a Keene...)
Hard to say for sure without seeing your ground/setup/equipment onsite...but sometimes simple could be best? What is the size fraction of the fines passing over your sluice runs? We are mining a large deposit with fine, well flattened flakes (average .5-2mm) and have been screening to minus 1/4" (lower screen); upper screen 1 1/4". This season we are switching the lower screen to 1/8" this will allow gold to pass to sluice runs but remove a lot of unnecessary small pebbles which interfere with the vortices created by the riffles. We anticipate significantly more through-put, along with better gold recovery. At the same time we will have less material flowing into the settling ponds. Our previous operation was a near source/coarse gold deposit and required coarser screens/nugget traps. A lot depends on the geology of your deposit... It may just be the nature of placer operations to have significant time into hauling pay, dredging ponds, moving coarse tailings etc. That said....having the plant on an excavator undercarriage could be a huge time saver, just move the plant to the pay and deal with the tailings in a more conventional manner. I know we have enough trouble on a 170' head lift of just clean water (4" for our small operation, Godwin dri-prime pump). I have been warned just the silt content of our large river in spring flood will be hard on the pump impeller and volute.... Our pump is working at max. the whole time and I know it is hard on the mechanical seal....Frictional loses/horsepower requirements when pumping a slurry must be enormous? There are a lot of efficiencies to be had in order to keep the cost/time of processing the pay down; it comes down to finding which ones are practical for your site....Good luck!
For sure...I know that impeller and mechanical seals for our small Godwin Dri-prime pump are really expensive! I have seen a lot of really large pumps from the oil patch passing through Ritchie Bros. Nisku, perhaps there is some application in the oil patch that would work?
ALL spare parts for Godwin pumps are expensive..!!
Check out Toyo sand pumps. Some are electric and some hydraulic.They make them for small marine dredging jobs. I remember doing a sheetpile cofferdam on the Yukon River in Whitehorse that needed to be kept dry .once it was dug down to elevation we dug a well in each corner and set 4" electric submersibles to keep the water down.Those submersibles pumped a substantial amount of sand,enough that the settling pond about 100 feet away ended up with truckloads of sand after a couple of weeks pumping.I know thats nothing compared to your volume,but we couldnt stop those little pumps from picking up the sand. A bigger dredge pump might work pretty well. Ive spent some time around the Yukon doing pile driving jobs,I had to get out of there before i caught the gold mining bug.Always admired the gold miners ingenuity in extracting $$ from dirt. Hope your mining goes well for you.
Your operation is very similar to mine. My gold is mostly fine and well traveled/flat flakes. The larger flakes are often folded over themselves. There is also a fraction that hasn't traveled at all. Fine but very rough with quartz still attached. 5 by 14' screen deck. 1" punch plate top deck and 1/2" bottom screen. I've been thinking this winter about trying some finer bottom screens for the same reasons you mentioned. My best guess we average around 70-80 loose yards an hour. And 30-40% of that is 1/2" minus going down the sluice runs. 26' long sluice box. 4' angle iron on top fairing to 8' expanded metal on the bottom. Our bottleneck is the sluice box. Could really use more water but the 6" pump is getting tired. Brought a newer bigger pump up last year but never got it set up to use. (Remote fuel source and roof overhead and containment underneath) Pumping 400' with 20 foot of lift. The deck itself seems to wash better the harder it's fed. More rock on rock rubbing action. You made my mind up trying finer bottom screen. Thinking 3/8". You ever have trouble pegging and plugging the finer screen? A couple old pieces laying around here are plugged solid so I've been hesitant to try it. Really hard to change up what works. Short season. 4.5 hrs from town... If you can't find it there your 3 weeks from anywhere... Figure the first step would be to try pumping gravel away from our current setup. If it doesn't work drag the thing out of the way. If it shows promise go all in the following year.
Sounds like you got out just in time. It's a disease. Once the gold bug bites your addicted for life! Lol Edit. Replying to Tugger2
Indeed, have learned that...!
Thanks for that info, very interesting.... Our 1/4" lower screen has had no problems with plugging and stays remarkably clear. The gravels are very rounded fluvial wash so that helps. The last property we were on had a lot of highly angular/fractured diorite/tuffs, these 'triangular' type fragments could indeed clog the lower screen (1/2") We are hoping the 1/8" screen will work out, I do have some concerns about clogging as this is a pretty aggressive move.... Last year I could only feed at 18yards/hour due to the sand load on the sluice runs as well as being limited on feed by our 5 ton feed machine (Deere 50D). Just pickup up an older Hitachi EX100-1 to allow a faster feed rate. This will also help with coarse tailings during each 'Batch'. I work mainly by myself so usually do 2 batches/day. Hoping to double feed rate to 36yards/hour. My experience in our ground has proven the finer you can screen (dependent on expected gold particle size) the better the recovery and overall gold totals. I am thinking of building some hydraulic riffles this winter to test out (we have a large amount of magnetite/hematite)
You have probably read this, but I will put it up in case it is helpful to anyone else....
My original sluice box had a set of hydraulic riffles. I had lots of trouble with the holes plugging with organic matter so I took them out. Been thinking about building another set to try again. The Macon equipment website explains a little bit about the self cleaning filter they build. Basically it's a screen parallel to the water flow. Hose nipples on one side with the majority of the water flowing parallel on the other keeping the screen washed clean. My experience filtering the water is a must. I tried progressively finer screen on the suction hose in the creek but couldn't get fine enough to keep the riffles working without plugging the suction screen in a couple hours of running. Really hard on the pump. Had an accident and Broke a bunch of toes last week so I've been laid up. Wife subscribed the gold rush and Freddy Dodge shows to keep me from going crazy. Never sat down and really watched others wash rocks before. In between yelling bull **** at the TV I got all kinds of ideas now. Lol
Definitely a huge problem with trying to keep out the organics...main reason I have never really went with the hydraulic riffles. Your experience makes me think I may just forget that idea for now..... Sorry to hear about your accident...but yes one can definitely get some useful bits of info from these 'shows' Your plant looks really well thought out!
When I try hydraulic riffles again I think I will build a filter like Macon does. But build it in a 3 way box. Water passes straight through to the plant. Screen with hose couplers to the riffles on one wall. A large gate valve directly across that would act as a bypass valve for start-ups and shut-downs. Splice it into the main water line 5 feet from the plant. With camlock fittings all the way around a guy could easily wash it out and bang it around if needed. If the gate valve is big enough a guy could reach in for "surgery" on the screen if needed.
Thanks for all the interest/ideas. From my research concrete pumps won't handle the volume. Manure type pumps won't handle the abrasives. Volute type takes too much water and won't handle the elevation rise. I have a Eddy pump (industrial dredge type) going over the criteria. Pricing is probably the killer for a untested system out in the bush.
My suggestion would be to elevate the crap out of your washplant to give you more holding capacity for fines. A big elevated pad would be something you could do with the equipment you have. Otherwise you would need a sandscrew and a conveyor which adds complexity. I also placer mine in BC and waste rock (mines inspector told me not to call them tailings lol) management is critical. lol- I just went back and re read your first post and you said the same thing........ Let us know what you end up doing!
While having no knowledge at all of placer mining, I always thought some type of hydraulic, self dumping water and rock fed centrifuges dumping into Tweco screeners would be of help. Not very hard to build, just not sure they would do anything We used these in copper recycling plants and they worked well and required minimal maintenance.
Years ago when gold broke the $500 an ounce barrier a mate and I looked a getting a small dredge that could be back packed into areas for prospecting. 2 items were the pump and sluise box, both floated. To suck up the gravel it used a venturi and could pick up stones as big as 4" and put up to 12tons and hour over the table but 4ton an hour was best, all of this with a 5hp motor. Would a scaled up version of this work? No gravel wrecking the pump would have to be a plus. Having the pump on the water in a pontoon will make it more efficient, maybe a jet drive pump could work if the tail pipe was modified to fit a hose.