"Last week, Coeur d’Alene announced that the Morales administration had assured it that it wouldn’t be nationalized; now it appears that the Pan American Silver’s San Vincente and Swiss-owned Sinchi Wayra’s mines will not be affected."
The reason? It seems that the unions at the mines don't want them to be "recovered" (i.e. nationalized) by the State. Meanwhile the deputy mining minister said, "A recovery of the mines that were owned by the State mining company Comibol and had been passed over to private mining companies for their administration and exploitation had been considered; but the condition was that the unions working in each of the mines were to agree to this (recovery). All the unions are against (this move), it's not going to happen."
Read more at Bolivia Weekly here.