th ▁century ▁Mexico , ▁associated ▁with ▁great ▁and ▁sudden ▁wealth . ▁▁ ▁Some ▁modern ▁writers ▁on ▁lost ▁mines ▁have ▁assumed ▁Plan chas ▁de ▁Pl ata ▁to ▁be ▁" lost ," ▁although ▁the ▁location ▁has ▁always ▁been ▁well ▁known . ▁ ▁After ▁the ▁initial ▁pla cer ▁silver ▁discovery , ▁the ▁district ▁was ▁idle ▁until ▁silver ▁ve ins ▁were ▁discovered ▁in ▁the ▁vic inity , ▁and ▁between ▁ 1 8 7 2 ▁and ▁the ▁ 1 9 3 0 s , ▁at ▁least ▁six ▁mines ▁operated , ▁and ▁ore ▁was ▁treated ▁by ▁a ▁stamp ▁mill ▁and ▁pan ▁am alg am ation . ▁ ▁The ▁amount ▁of ▁silver ▁produced ▁is ▁not ▁known , ▁although ▁the ▁amount ▁of ▁ore ▁m ined ▁has ▁been ▁estimated ▁as ▁between ▁ 5 0 , 0 0 0 ▁and ▁ 1 0 0 , 0 0 0 ▁tons . ▁ ▁No ▁min ing ▁has ▁been ▁done ▁since ▁the ▁ 1 9 3 0 s , ▁but ▁a ▁Canadian ▁firm ▁has ▁had ▁some ▁encourag ing ▁results ▁from ▁expl oration ▁dr illing ▁in ▁ 2 0 0 7 . ▁ ▁References ▁and ▁further ▁reading ▁ <0x09> ▁ ▁This ▁article ▁incorpor ates ▁text ▁from ▁Arizona ▁/ ▁Plan chas ▁de ▁Pl ata , ▁a ▁ ▁public ▁domain ▁article ▁produced ▁by ▁the ▁US ▁National ▁Park ▁Service . ▁ ▁External ▁links ▁Canadian ▁company ▁acqu ires ▁historic ▁Plan chas ▁de ▁Pl ata ▁district ▁Arizona ▁and ▁Plan chas ▁de ▁Pl ata ▁at ▁National ▁Park ▁Service . ▁ ▁Category : Ge ography ▁of ▁Son ora ▁Category : Pre - state hood