Mine your own business

This post at Powerline caught my attention today, because it relates to a subject of which I actually have some knowledge. Basically, John Hinderaker disputes the veracity of an article which references 500,000 abandoned mines in the Western United States.

So I did a little digging and found out the truth of the matter:

According to the estimates provided by the states, there are 425,000 abandoned mines in the Western US. Links to most of those state authorities can be found at a site run by the Westerners for Responsible Mining, who say it’s “more than 500,000.”

Note that I will only accept state numbers as valid, and reject all non-state entity estimates, as they may be tainted. Here’s a list of the states and number of abandoned mines they claim:

Arizona: 100,000
California: 39,000
Colorado: 23,000
Idaho: 9,000
Montana: 6,000
Nevada: 200,000 “mine shafts and mine features” with 50,000 dangerous
New Mexico: 20,000
Oregon: 126
South Dakota: 900
Utah: 20,000
Washington: 3,800
Wyoming: 3,200

As you can see, there is quite a wide discrepancy between two states (AZ and NV) and everybody else. The total is 425,000, with an average of 35,000 per state. It’s clear that there are probably wildly different ideas about what constitutes a mine in South Dakota compared to Nevada.

Nevada says that they’re counting both “mine shafts and mine features” but only 50,000 are dangerous. If we use the 50,000 number, then the total number of mines drops to 275,000.

With a more realistic Nevada, Arizona now accounts for 35% of the total abandoned mines in the western United States. This seems particularly unlikely. I would suggest we assign to Arizona the average (~25,000), in place of 100,000, and say that their inspectors are being too strict about what constitutes a “mine”.

That brings the total down to 200,000 abandoned mines, quite a bit lower than where we started. And if you really undertook a mapping scheme to figure out where they all were, I’d guess that the large numbers would come down a lot, and the small numbers would only go up a little.

My opinion: the 500,000 number is vastly overblown, and is more likely between 80,000 and 120,000 (with fewer than that representing a danger). But given the apparent accuracy of the current numbers, you can state that the number of abandoned mines is anywhere from 2,000 to 2,000,000 and be within the realm of uncertainty of the current estimate. So you can certainly do worse than say 500,000, which comes directly from the states themselves.

Did anybody else notice that this was a completely serious post? What's up with that?