can you explain how you calculate the 50M aud at worst of free...

can you explain how you calculate the 50M aud at worst of free cash flow. If i calculate cost of production here in australia based on mine
scoping/feasibility study, of cost price for phosphate mining which also includes transport costs {185 aud tonne.} which would give profit at current price 45 aud a tonne exchange rate 0.65 usd. now 10 tonne of phosphate to one tonne of phosphoric acid. Can you tell me how you receive the minimum of 50M free cash flow, given other input costs to the yellow phosphorous plant. my estimates give cost of one tonne of phosphorous to be about 3000 usd a tonne. cost of transporting yellow phosphorous {a hazardous substance} higher than dso product. less product to transport though. are they going to pay us a premium. or will it be saved on the electricity we make using solar and sold to the locals in the area?