Boy howdy you ain't kidding there amigo! You had to hunt through musty old newspaper piles in the courthouses, visit the historical societies, talk with the old timers at the saloons, even the guy pumping gas at the gas station was a possible source for a new lead. We have it way too easy today.
I would not dismiss the tales of the Cement mine so quickly or off-handedly. It is an unusual type of ore granted, but hardly unknown either - here in the Black Hills a number of rich gold mines were actually just exactly that kind of ore, a cement of sand, clay and gravel loaded with gold. In this case they were believed to be an ancient paleo-placer, a beach placer that existed in the Cambrian age when the hills were islands in a massive inland sea. Just because promoters and treasure writers have been peddling a story for a long time, embellishing, distorting and even deliberately misleading their readers to make a fast buck, does NOT mean that the original story is not based on a very real deposit of gold. (Or silver, diamonds, even platinum hint hint!)
Still looking around for such a story of a lost platinum ledge in Death Valley, so far no such luck. But I never say die either. Please do continue;