The issue seems to be over a $100 million copper deposit. Copper is sitting around $2.90 a pound, which means the deposit is roughly 3,4482,758.6207 pounds (rounding up). There are 454 grams per pound (rounding up), which means roughly 15,655,172,413.7931 grams. US pennies, from 1864 to 1981 (except for the year of 1943) were 3.11 grams at 95% copper, making about 2.9545 grams of copper per penny. That means, it'd take about 5,298,755,260 pennies to cover the projected copper haul of the mine (ironically, only about $52,987,552.60 in currency - which is about half the projected value of the mine.) Subtract labor hours, equipment, and transportation fees - you could probably get away with paying much less than that. A penny drive starts to sound like a reasonable idea. Of course, the US is burning $50+million a year in actually producing pennies (even after going from mostly copper to mostly zinc), at which point the whole exercise seems kind of silly - would almost make more sense to have a huge penny drive to return the coins to the US mint and have the gov't buy the rights to the mine straight out.
While it sounds like a lot of money, $100 million isn't that much in the grand scheme of things, especially when China already sees 10 million visitors a year just for the Great Wall and rakes in total tourism revenue in the ballpark of $185 billion. You would think Afghanistan or China would find some other way to turn a profit on such a landmark rather than digging it up and destroying it forever.