What are ways in which the waste powder coating fines are currently
used? Or do they all land up in the dump? Statistics supporting this
will be highly appreciated.

My guess is they mostly go to the landfill. At best they would be
slightly contaminated. At worst they would be a mixture of several
colors plus some dirt. If you are ready to pay a dollar a pound, some
users will save some for you, but most would not be willing to change
their working proceedures to improve the quality of what they sold
you.   Neil

That is exactly what I want to know ....What to do with this waste powder?
In what ever condition it may be, contaminated or in good condition?
Are any products being made form it?

If it is in reasonably good condition, beginers could use it to
practice powder coating. Even rather badly contaminated it could be
used to color cement and concrete at perhaps 10 cents per pound. Sorry
a real researcher did not answer your question.  Neil

Waste powder may not be good to practice spraying. It will have its own problems. 

I am really intrested to know the uses of it as a chemical really.

I want to know where is your location. I may can help you out if you
have some waste powder.