A neighbor of mine is trying to fill his new pool and on his property he has a old well that the preveious owner collapsed. He wants to use this well if he can to keep the strain off of his current well and he would also like to use it for irrigation. The water table has come back up in the old well. (it's been a few years since it's been used) What I need to know is how we can blow it back out to use it. There's water in the casing, but if you try to pump it out sand will start pulling up. We've been using my compressor @ about 25-40 psi. and have made some progress, but I'm clueless as to how long to do this or if I'm even going about this the right way.

Maybe sombody could point me to some detailed instructions? I want to do this myself for the learning experience so I can install my own wells in the future.

Man, I don't know if it's even possible. Once the well has collapsed, it's done. You'll always pull sand/debris through the pump (which is very very bad for the pump in case you didn't know).

Maybe there's a way that a professional can go in and drill it deeper and re-case the bottom, but I've never heard of that happening. It would be easier to just drill a new one.

How deep is this well?

If the water table has come back, can you just move the submersible pump up higher so that it's still under water but not down where it's pulling sand?

The table starts about 8ft. and we're at about 30ft. (We don't kow how far the casing goes down) It's a shallow well and we're using a above ground pump. We've tried going a couple of feet higher, but we still pull sand.

BTW, thanks for fixing the posting problem earlier Tobus.

You should be able to tell where the water is at and where the sand starts by feel. Pull your pipe out of the well and lower it back down. You should be able to feel when it hits dirt/sand etc. You need to be a good 5-10 feet from the bottom of the well.

Tobus is right, not much can really be done in this case.

You can fracture a deep well in solid rock with dynamite, and that sometimes works. In a shallow well in sandy strata, -

Some things you can try though -
I reckon you got a jet pump on this well?
Like Dave says, get the inlet up outta the sand.
How much does the well drop when you pump it? Raise the inlet up as much as you can.

Choke the pump back a bit. Use a ball valve on the outlet and cut the flow in half.
Less flow will drop the well level slower, and draw less sand.

A smaller pump could be used, if you got one laying around.
You could even use a very low flow pump ( a cheap DC bilge pump on a solar panel? ) to fill a cistern.

I've never tried this before because priming a jet pump can be a big enough pain as it is, but possibly a sediment filter on the inlet might be a solution if sand continues to be a problem. That is after you find the bottom of the well and lift the inlet higher than that. It could be just a simple booster pump and not a jet pump but the principle is the same.