[smiley]

Kudos to pup55 for digging this up

http://www.roperld.com/minerals/metalsum.htm

Quick summary: David Roper has been modeling the depletion of various ores, coal, oil and gas. The link contains an abstract of the book he wrote in 1976. He use the same type of analysis as Hubbert, although he uses asymmetrical curves.

I could be mistaken but I can't recall ever hearing his name mentioned before. Has anyone got more extensive info on him, his methods, his predictions and and how they have worked out?

[MattSavinar]

$this->bbcode_second_pass_quote('smiley', 'K')udos to pup55 for digging this up

http://www.roperld.com/minerals/metalsum.htm

Quick summary: David Roper has been modeling the depletion of various ores, coal, oil and gas. The link contains an abstract of the book he wrote in 1976. He use the same type of analysis as Hubbert, although he uses asymmetrical curves.

I could be mistaken but I can't recall ever hearing his name mentioned before. Has anyone got more extensive info on him, his methods, his predictions and and how they have worked out?

[DoctorDoom]

I fundamentally don't understand why resources other than energy are being "used up". Seems to me most of them can be recycled (some, like steel, already are) and the main problem is that the cost of virgin materials is still so low that it's hardly worth bothering. (And of course a big part of the cost of recycling would be energy again.)

[smiley]

$this->bbcode_second_pass_quote('', 'I') fundamentally don't understand why resources other than energy are being "used up".

[Soft_Landing]

$this->bbcode_second_pass_quote('', 'I') fundamentally don't understand why resources other than energy are being "used up".

[pup55]

If you go to Dr. Roper's home page and click on his vita, you can check his resume, which suggests he is a Renaissance Man, high power theoretical physics degree from MIT, Habitat for Humanity, Actor, trombonist, electronics guy, lot of experience with mathematical modeling, been around a little bit.

At the bottom of this link is another link, with an explanation of depletion theory, in which is included a fudge factor for human behavior.

http://arts.bev.net/RoperLDavid/minerals/minerals.htm

[dmtu]

Nevada has become the largest gold producer in the states largely because new technology came about in the late 1980s wherein microscopic gold encapsulated in pyrite could be extracted through rapid oxidation and absorbed via cyanide. This vastly increased the US geologic gold reserve. While there may be no parallel to oil, it is interesting that he called the peak year for gold 1916 but I'm relatively certain this is not the case (I'd look up the numbers but...). It only took 70 years to find the tech needed to extract that gold, imagine the possibilities.

[Leanan]

Roper claims the U.S. has not yet peaked for crude oil and natural gas.

Anyone figure out how he reaches that conclusion? The chart he prints is too small to read (at least on my monitor).

And the page is dated 1976. Obviously, it wasn't put up then. But are the data and conclusions that old?

[pup55]

http://www.arts.bev.net/roperldavid/min ... udeoil.htm

The following link is to his recent modeling based on the Verhulst function. His model predicted a 1976 peak for US crude oil, and the global peak in 1999 or so.

Because of noise at the plateau, the model fits better on the way up/down.

[Leanan]

So it's basically the mathematical peak vs. the actual peak.

Looking at his charts, recession and conservation really can make a big difference. It's awfully hard to take those into account for depletion modeling, though.

[pup55]

bump

[unbrkable]

pretty hard its damn near impossible

[Harlequin]

Uh...whats with the bump? This thread is years old, is there a reason for the bump?

[pup55]

Sorry:

This topic came up in a recent conversation about metals and mineral depletion.

Roper had done a lotof work in the 70's and this thread had a lot of the links to his work.

[MD]

Good find pup, thanks for digging.