just release latest announcement, page-15

XRF is X-ray fluorescence. They bombard the sample with high energy xray or gamma rays and then compare the emission with standard known element emissions.
It is used in many industries. If you are keen start with a study of Planck law or the Bragg equation.
Other than that its a special box you throw dirt in and after the lights stop flashing it tells you what the dirts made of lol.
You can not report on the field tested samples but it can save you a hell of a lot of time drilling in places that have nothing and help you focus on the promised land :)