help please

I have been following MAK for a while, great story so far and looking good going forward. It seems high phosphate prices and MAK's large phosphate deposits are driving the current and potential growth in SP. I have done some research (but not enough to be fully informed so I was hoping to take a short cut and ask for help from some well informed MAK investors) and what I want to know, to allay any doubts I have as a potential investor, is regarding the purity of phosphate deposits recovered from ancient geological formations. Previously most of the worlds phosphate deposits mined for fertilizer have come from age-old guano ie pure phosphate rich bird poop (like at Nauru or coastal South America). What I would like to know, is what is the degree (if any) of heavy metal and/or uranium contamination in MAK's phosphate deposits. I understand that crop fertilisers must be very clean of such things. Am I unecessarily worried here? If heavy metals etc are present, are they easily and cheaply removed? Thats all.

PS I have been to the MAK website and cannot get any information about this concern