Crude oil depletion can be a good indicator of what can happen to the price of something that gets depleted.
The following is a extraction/depletion curve for U.S. crude oil. The blue area represents the U.S. crude oil reserve. As you can see, the U.S. has already peaked in oil extraction in 1970 as their reserves are diminishing.
Now let's look at the world crude oil depletion curve. Almost the same, but the peak is delayed from 1970 to 2000. It's this curve that we need to monitor to guess what will happen to the crude oil price.
Then, when world crude oil extraction peaked in 2000, we got a second spike in crude oil price from $33/bbl to $110/bbl.
Now, what I find interesting is that we can easily use this little "theory" on other things and most particular on silver, because I believe we are nearing a depletion stage now on silver in a few years.
So this is the current world silver extraction curve. We see that the peak will occur in 2020.
The extraction curve can be seen below. You can see that silver extraction will rise the fastest in 2020. After that, we will only have lower and lower production going forward. And that's the time when the silver price will start to surge.
Learning from the oil depletion curve is a good way to predict what will happen for silver a few years from now. And it will be rosy.