Transmutation is the process by which the nucleus of an atom changes so that a new element is formed. Transmutation, the change of one element into another as a result of nuclear changes, can occur naturally or by artificial induced means.

Examples
    Transmutation natural conversion
Coal turns into diamond
Uranium  turns into lead.
etc.

    Transmutation artificial induced means
The basic artificial transmutation is done using a particle accelerator

(c) It is sited that Uranium 238 in coal wastes is gradually converted to Plutonium 239 through exposure to background neutrons.This and other science related information can be found in http://www.ornl.gov/Library/library-home.html. A good source for science experiments