Rule, more than 20 new mines per decadeHi Rule. where do you get 20 mines per decade from? Just think about gold. The annual
worldwide output of gold is around 80,000,000 ounces. 20 new mines per decade is two per year. On average, those two mines would need to extract 80,000,000 ounces of gold over their entire mine life. Of course, the 80,000,000 ounces in a given year would come from more mines, but the average mine would need a resource of 40,000,000 ounces. That is way too large. The average mine is much smaller, and hence more than two mines are being built per year. And then there is copper, silver etc.
I found a web site
https://www.rmg.se/Doc-PDF/WorldMining.pdf
with a map of all mines in the world.
There are certainly lots of very small mines, so a cut-off is needed.
For gold mines they use a cutoff of 30,000 ounces per year (and something else for silver etc.) and there are 384 of such mines in the world today.
For base metals, they use 100 kt.year copper (and simlar for other metals), and they know about 301 such mines.
So, with those cutoffs, there are 685 mines in the world. Assuming an average mine life of 30 years, that gives around 23 new mines per year or 230 per decade.
Using yor 5000 companies figure, that would mean that 230/5000 = 4.6% of the companies find a mine. It must be worse for the juniors, because an average major finds more new economic deposits than an average junior.
As a side note, we can estimate the average extractable resource of a new gold mine.
Let us say that out of the 384 gold, silver, PGM mines, 250 of them are gold mines.
Using a 30 year mine life again, that gives 8 per year, which is still a massive 10,000,000 ounces resource. That sounds too large to me, so maybe there are more mines than this web site knows about, or all the small mines contribute a lot. I don't know.
Cheers.