From the economic pont of view, Afghanistan does not seem a country to fight for. According to the OEC website, currently
“The top exports of Afghanistan are Gold ($968M), Grapes ($214M), Insect Resins ($129M), Other Nuts ($113M), and Tropical Fruits($97.4M), exporting mostly to United Arab Emirates ($1B), Pakistan ($544M), India ($485M), United States ($35.6M), and China ($29.1M).”
This list does not includes the illegal Poppy trade, which is estimated by Forbes to be about 350 millions. The total volume of export from Afghanistan is about 2,6 billions of dollars.
However, several reputable news outlet recently claimed that the mineral reserves (from lithium to rare earths) in Afghanistan could be worthy 3 trillions of dollars:
The Taliban are sitting on $1 trillion worth of minerals the world desperately needs (CNN business, 19 August 2021)
Afghanistan Is Sitting On A Gold Mine. Literally. (Forbes, 30 August 2021)
Lithium and an Unexpected Battle for Energy Transition in Afghanistan (The Diplomat, 10 September 2021)
Is Afghanistan really sitting on mineral reserves worthy 10^3 times its GDP? All of these articles refer to a 2010 Pentagon memo, which allegedly says that Afghanistan could become “the Saudi Arabia of Lithium” [1]. The source for the existence of this memo is this 2010 NYT article:
U.S. Identifies Vast Mineral Riches in Afghanistan (NYT, 14 June 2010)
I was not able to read the report of the US Geological Survey on which these estimates are supposedly based on, but (comparing with other divulgative articles) the figure of one trillion looks realistic. Nevertheless, the framing of the NYT article was met with some skepticism by experts in the area. Three days after the publication of the NYT article, Jean McKenzie wrote:
Once the Pentagon packaged the data by tacking on a speculative price tag — $1 trillion — and adding a snappy sound bite here and there, a three-year-old report based partially on decades-old data collected by the Soviets became the biggest story on the planet.
The problem is that the minerals are hard to extract, in a country devoid of road and infrastructures. In a year in which the price of copper was exceptionally high, a Chinese company tried to set up a mine in the Afghan copper basin of Mes Aynak. Roads and railways should have been built, as well a 400 MW coal power plant; and the population should have been relocated. Then they gave up when the price of copper fell back. Notice that Mes Aynak is probably one of the best case scenarios, since it is close to the capital Kabul.
According to widely reported estimates, the war in Afghanistan costed 2 trillion dollars in operations. Besides, 1 trillion dollars is less than two years of the US military spending. So, even if the US government could seize all the Afghan minerals, it would not have gained money from this war (of course, the balance might have been different for weapon-manufacturing companies and other actors interested in the war).
[1] Actually, gold and copper are probably much more important than lithium. The Lithium reserves of the whole world are estimated to be 8×10^7 metric tons (although more than half of it is in deep layers). The price of lithium fluctuates a lot, but taking 10000 $ per metric ton as an order of magnitude, this amounts to 800 billions worth of lithium reserves.
Forensic Oceanography 