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Dewatering pump options - approx 120 m LIFT

Dewatering pump options - approx 120 m LIFT

(OP)
Question re mine dewatering pump options. Looking at suppliers/models/single stage centrifugal/multi-stage. We have an underground transfer pumping duty. Flow rate is approx 100m3/h. Head will be in the order of 120m to 130m. Currently the lads are looking at sulzer centrifugal. Mine is long life. I would have thought a small multi-stage, or double suction would have been more appropriate rather than a high speed (2 pole speed) centrifugal that is going to beat itself to death in a short period. Any comments? Water will contain some small percentage of solids. Maybe 3%. Regards

RE: Dewatering pump options - approx 120 m LIFT

There are other pump companies besides Sulzer who could supply pumps for this application which is really nothing special or difficult.
A google search would go a long way.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

RE: Dewatering pump options - approx 120 m LIFT

I see no problem with a single stage end suction running at 2 pole speeds. Check the solids and pH of the water, choose appropriate metallurgy.

RE: Dewatering pump options - approx 120 m LIFT

Keep in mind that wear increases as the cube of the speed increase, so if there are ANY solids in this mix, you want to be careful with a 2 pole. You might look at a two stage splitcase. As Artisi is indicating, Sulzer is probably overkill here as their expertise is in process/API pumps, not water pumps.

If you have sand in the pumpage, take good care of material selection. Don't let anyone talk you into mechanical seals if there are solids.

RE: Dewatering pump options - approx 120 m LIFT

Why did you capitalize the word LIFT ?

Just to clarify for gawkers, you can't drain water out of a 120m deep hole with a pump on the surface.

You have to put the pump down in the hole.

In the case of a well you do it by dangling a submersible pump on a cable that holds the pump and its discharge pipe up and transfers electricity to the pump motor.

In the case of a mine you may have other options.

Mike Halloran
Pembroke Pines, FL, USA

RE: Dewatering pump options - approx 120 m LIFT

Ha ha! Excellent point MH. Before my original post, my first thought was to clarify exactly your point; ain't nobody liftin' water 120 meters. However, technical language has become so sloppy these days. I supposed Pumpingtips had supposed the pump located at -120 meter grade level.

If the pump is actually located at the surface and expected to lift 120m, please fill us in on how the warranty battle ends up.

If, as physics demands, it is located subsurface, this is not a difficult service. Material selection and speed will be your two most important decisions.

RE: Dewatering pump options - approx 120 m LIFT

(OP)
hahaha. So interesting to see the different calibre of responses. Dubmac, I think you appreciate that this is not so straight forward as some suggest. Two stage split case, could be. Location for these pumps is 1200m underground pumping/"lifting" up to the main GEHO pump station for the main 1100 m "lift" to surface. It's a critical mine duty. I thought one of you might have mentioned Mono progressive cavity pumps. This was done on previous owner mine. I'm just not comfortable with the Sulzer 2 pole selection and am trying to get the guy responsible on client side to look at options. At Escondida they had large thickener overflow (surface) return water pumps (15,000 m3/h), Worthington double suction, that lasted 6 weeks before the supplier started to improve materials using duplex, etc. They also saw solids and other process chemicals which added to the problem. I personally would like to see monos in this case but not 100% sure of other options.

RE: Dewatering pump options - approx 120 m LIFT

(OP)
I should add that the 15,000 m3/h example was five pumps operating, not one!... just to... you know, make sure people stay calm through these difficult times.

RE: Dewatering pump options - approx 120 m LIFT

I was going to say look at prog cavity if you've got"dirty water" but not sure if they go up to 100 m3/hr.

Vendors like gould or flyght have more experience with that end of the market. Also you need to decide if flow is fixed or variable. Problem with pumps with high fraction of static lift is the unless you're on a steep part of the pump curve flow can vary a lot if anything changes a small amount compared to a PD pump.

A lot depends on what this 3% is actually made of.

Remember - More details = better answers
Also: If you get a response it's polite to respond to it.

RE: Dewatering pump options - approx 120 m LIFT

Aha...yes a bit clearer picture. A PC pump would be a great choice; probably would require a couple of them in parallel to make the flow requirement. Mono had a proprietary design using a "flexi-shaft"; a very clever option to get away from the geared universal joints that commonly plague most PCs. The only drawback to the flexishaft was that it made the pump so long; might not be an issue in this service.

As an alternative to the hard metal materials, you might look at a rubber lined pump. Goulds and Worthington used to make good ones for use in abrasive sand or ash services. Weir is also a good place to look for pumping all kinds of nasties.

I'm not familiar with Sulzer models for use in anything but fairly clean process fluids; API type stuff.

RE: Dewatering pump options - approx 120 m LIFT

Mather and Platt used to be the prime choice for mine dewatering but as they were designed essentially as centrifugals , they needed almost zero solids in the water to maintain life. For any significant sized mining operation, the design of the settling facility and disposal of the slime was bread and butter engineering. Mars pumps, or their newer equivalents, can handle almost any amount of slime , but dont come cheap. If it was me , I'd be looking seriously at two 58HP Flyghts in series. These will handle 3% solids without excessive wear. Suggest you focus on the solids disposal aspect of this before worrying about pump metallurgy. Non minng personnel would be amazed at the volume of solids that pumps can be expected to deal with at times.

RE: Dewatering pump options - approx 120 m LIFT

(OP)
Thanks for the well thought out responses. I'll take the comments on board and make some further reviews. I am really liking PC option even more. Regards

RE: Dewatering pump options - approx 120 m LIFT

Consider a 2 stage operation, pump to a holding tank half way and a second pump to the discharge point.

It is a capital mistake to theorise before one has data. Insensibly one begins to twist facts to suit theories, instead of theories to suit facts. (Sherlock Holmes - A Scandal in Bohemia.)

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