Not enough information
"Each kilo is worth about £500 and we estimate we will mine between 250,000 to 400,000 tonnes per year [of the raw ore used to produce indium] in the first phase."
I guess 1 kilo(gramme?) of indium is worth 500 quid, not 1kg raw ore. But, how much Cornish ore is needed to produce 1 kg indium? Depending on the answer the £500 could be less attractive than it appears now...