3 ms·

So it becomes ore again? It won't just go away.

• dredmorbius 5y ago
  "Ore genesis" is the term of art in geology for how various mineral ores form. Typically this involves a source, transport, and trap. Biological processes can play a major role (iron, limestone). https://en.wikipedia.org/wiki/Ore_genesis https://en.wikipedia.org/wiki/Ore_genesis Useful ore deposits tend to be vast, with absoutely immense amounts (many trillions tons) of paydirt. The value of ores are that the minerals of interest are concentrated, sometimes to very high levels (50% or more of total material), though increasingly lower-grade ores (1% concentration or lower) are utilised. This means that you've got to move 99 units of mass for every unit of primary mineral extracted (overburden). Even very large human formations are small by geological standards. The World Trade Centre towers contained about 200,000 tonnes of steel. That's a lot for humans, but a minuscule amount on a geological scale. (https://hypertextbook.com/facts/2004/EricChen.shtml https://hypertextbook.com/facts/2004/EricChen.shtml) Current iron ore extraction is on the order of about 2.5 billion tons/year. That's roughly 1/3 ton per person on Earth. https://www.visualcapitalist.com/all-the-worlds-metals-and-minerals-in-one-visualization/ https://www.visualcapitalist.com/all-the-worlds-metals-and-m... Vaclav Smil's Making the Modern World goes into depth on material use in contemporary civilisation: https://www.worldcat.org/title/making-the-modern-world-materials-and-dematerialization/oclc/1261614944&referer=brief_results https://www.worldcat.org/title/making-the-modern-world-mater... (After water and oil, sand and gravel are our most-used material, then concrete and iron/steel.)