I presume you already have some info and this is probably repeating what you know, but the price is right so here goes... The lost Tayope has been called the richest and most romantic of all the lost mines. This lost silver mine is supposed to be located in the Sahuripa district just north of the Vacatete mountains of Sonora, Mexico. The mine was discovered by the Spaniards in 1703, and for 47 years it produced some of the richest silver ore ever seen on the continent. The mine is located "about eleven miles south of the Cucurpe mission and about halfway between Cucurpe and Opodepe on the west side of the San Miguel River". The Tayope mine was closed after the great Indian uprising of 1750 and was never reopened. The old mine is located about 40 miles southeast of Magdalena, Sonora. (source - Lost Mines & Buried Treasures along the old frontier by John Mitchell.)

As far as I know, the mine has not been found yet - I may be wrong, though! Hope this is of some help - good luck amigo!