World iodine reserve - not for long?

Answering to a Linkedin post by our colleagues from SQM we had to lift the veil of secrecy for changes in the world iodine reserves brought by our R&D team's work results. 

That's a strange way to calculate iodine reserve, really. Earth mass is 6.6 sextillion tons so 0.4% of it will be 2.31*10^19 tons. That would have taken millions of years for Humanity to consume, correct? No.

Here comes limitations. First, the base for calculation should be planet mass reachable for drilling i.e. top 23000 feet, we don't care about the planet mass. Second, we should exclude ocean bore and consider just a landmass drilling. (At least for now, thought we're working on that.)

And third, what exactly are we going to drill/excavate? Iodine comes either from caliche to excavate (Chile) or formation water to drill at several known spots (USA, Turkmenistan, Azerbaijan) and probably more to be discovered. And the ocean of course.

When we take these limitations in mind we'll come to the conclusion that there is not much extractable reserve. Not for a million years at least. SQM probably has about 800K mt in reserve (calculated through their announcement of 20 year world consumption), and our technology enabling a brine flowback brings roughly 20M mt on the table, i.e. another 500 years with the current consumption levels.

And yes, we all are expecting steady consumption growth that will bring reserve down to 100-150 years. Not millions of years. Not 0.4% of Earth mass. Much, much less.