I should note that in South Africa, there’s a requirement that data from reconnaissance be copied to the State as soon as the survey is done. It’s not released publicly unless a prospecting licence for that area isn’t taken out, but it does mean exploration companies don’t sit on data they’re not actually using for decades.
Very true. I was being a bit quick with my response.
What I observe, and where secrecy comes into things, isn’t that the exploration company flies the survey (something that is obviously impossible to hide anyway) but that they may purchase the already flown data from one of the usual survey companies, or from the government. This purchase is secret, and any processing by service companies specialising in such work, similarly secret. It can be a great earner for the survey companies.
I think most countries demand a copy of the survey data as a condition of exploration. Makes a great deal of sense.
i suppose in geophysics and drill log analysis. those are your basic tools for searching. as far as classical geology is concerned, it’s structural geology, sedimentology and paleontology (index fossils are critical.) but i think it’s the field of seismic exploration where oil and coal really made 20th century mineral exploration exciting.
as mentioned above, man’s relentless search for that black gooey stink has led to unrelated but interesting discoveries, such as the chixulub.
my field was in hard rocks, particularly for gold and copper.