Speaking of lost goldmines... I had a bachelor uncle that owned a general store just a block from our home. Had a large confectionary section complete with baseball cards. My uncle put me to "work" at a young age (this was in the 1950's) dusting, shoveling off the walk, moving merchandise, eventually working up to waiting on customers. He paid me in "trade"; model airplanes, model railroad stuff, kites, pop, candy bars and of course, baseball cards. I accumulated hundreds of 'em. "Willed" the collection to a younger brother when I went off to college, who promptly got bamboozled into dumb trades by older collectors. The remaining cards went into the attic when that brother went off to the army. The surviving cards completely "disappeared" when my mother was left "unsupervised" by our youngest brother.
Been poor ever since.