I am looking for any tips on pumping straght sand and water. I have done this at 200' but I have been ask to do 3000' I am thing high pressure water pump to help concrete pump flow it down the line at about every 500'

Sounds like gunite with out cement and water.  A REED Gunite machine and a compressor (and the system is what you need.

http://www.reedpumps.com/lova.htm

Putz has a self-contained machine for pnuematically conveying 'floor screed' it includes a decelerator to allow the sand to drop out of the air flow, without it shooting all over the place.

http://www.youtube.com/watch?v=d00Vnts31aE

http://www.moertelmaschinen.de/cps/rde/xchg/SID-3C6E00FC-412BE306/pmm/hs.xsl/6291_6303_ENG_HTML.htm

IMHO, this job is a disaster waiting to happen.  The saving grace is that it's not going to set-up in the pipes/hoses.   Without the benefit of lubrication of cement paste, it's going to eat up your cutting ring and spectacle plate.

Seems like a job better suited for a skid steer, wheel barrows or buckets.

Any more details on the job?   Is access the issue?  What is the volume?  Is the water required at the end as well?

sounds like trouble to me too i can't believe you got it to go through 200' without clogging, cement paste is the key soooo slippery

Sounds like you need a pump similar to what they use on a dredger.

does the job site have a smoking section, think about it.

Sounds like this sand water mix needs some cement depending on what strength you are trying to achieve?, lots of fly ash and i mean lots and for a little insurance some additive called viscosity modifier or ( v mar ) that will help keep the pressure from pushing the water out of the sand given the distance? JUST MY OBSERVATION HERE

you are going to need alot of water . Since you dont have to worry about strenght just start the water and use little sand as possible dont try to break any yardage records thats not going to happen with sand . When pumping dont stop unless you use water to clear out the line. The water is giong to hold the sand in sunpesion if you stop with out flussing the line you ARE going to plug. Make sure your valving in the pump is tight. pumping at that distance should not be a problem . keep a good watch on your pressure gage and jude for yourself on the amount of sand that goes into the hopper.