I would guess that you have formed barium sulfate (essentially barite) which is pretty insoluble, and not too easy to remove. This is probably a result of mixing of two different waters; one rich in barium (rich is a relative term, but over time it can add up), probably representative of reducing conditions with a low sulfate concentration and a second more oxidized sulfate bearing water.

Barite precipitation is common in a lot of oil field waters in the United States and it often contains a lot of radium. One thing to remember is that radium can co-precipitate with the barite and effectively concentrate into the solid phase, now you could have a naturally occurring radioactive material that may need to undergo an alternative disposal process. But more details are required.

I would also suspect that the screen interval, but this would depend upon how large the screen interval is, or more likely the pipe above the pump could be plugged. Plugging of the pipe above the well might affect the pump and cause it to overheat and eventually fail. If the screen interval was really large then mixing would be limited to a small portion of the screen but without more details this is only speculation.

Thank you for your message. We pump in a lake that is an old mine open pit. We cannot change the quality of water.

My research focuses on the passage of soluble barium mode. Is that the heat pump facilitates solidification of? Is that electric currents are electrolysis. It is to know the solutions.

What type of pump? Centrifugal with a suction line, turbine or submersible? I have used use special magnets mounted around the suction lines to keep the barium from precipitating when pumped with limited success. Also ran small amount of fresh water back through the pump when not operating to devolve out the precipitate. My guess is an old coal mine pit would have tons of sulfates. If over 2,000 PPM (from what i remember) and there is calcium you will most likely get gypsum precipitation Ca(So4). This could be the case if the water is treated with lime before it is pumped. Are you sure its Barium sulfate?

Well, the pump is Flight 21-51 (centrifugal and submersible pump).

I did make analyzes on the sample fixed to the body pump. To my surprise, there is no barium but a lot of calcium (25%) and carbonate. I also have some Fe, Mn and Mg. The final question is: What can I do to imitate calcium precipitation to the pump?
You told to special magnets, what it is? Is it compatible to calcium?

The water is not treated. In fact, the stratification of mineral elements is on the lake. We just pump to the area of the lake to go to the river.

My initial guess was probably correct; you have Calcium Sulfate building up on the pump. This stuff loves to build up in high energy places. I'd test the water for sulfates and if they are around 2,000 ppm then that is the problem. We used Magnetic Fluid Conditioning Units sold through Green Country Environmental Ass. LLC from Tulsa Oklahoma. We however had a suction line with a self priming centrifugal pump thus we were able to install the magnets on the suction line right after the strainer and before the pump. With a submersible this is not possible. Again I’d say we had limited success with the magnets. The important thing is to reduce the sulfates below the saturation point. Don't think you have any choice in doing this, thus you will continue to have the buildup. What works is to have a source of good (unsaturated) water to dissolve out the plating after operation. Ca(SO4) is soluble and will dissolve in good water (perhaps from the river). If you could lift the pump out between runs and put in a bucket with a small amount of river water running back through it might work. We did this as part of our normal operating.