Usser was just a typo and how it ended up in Chilean Nationalisation of Copper is beyond me. If you can find anything factually wrong with my eventual edit of that entry, let me know. I have to assume that you are an expert on the Chilean copper industry 25 years ago?
Three other mines were eventually nationalised, Cerro de Pasco's Andina operation, which went to Codelco, and the two mines, Los Bronces and El Soldado, owned by PeƱarroya's Disputada de las Condes, which were bought by ENAMI. Evidently these mines did not fit in with ENAMI's plans and Disputada de las Condes was subsequently sold (at a substantial profit) to Exxon Minerals.
Three other mines passed into State ownership. Cerro de Pasco's Andina project was nationalised and became part of Codelco. Compania Minera Disputada de las Condes, which operates the Los Bronces and El Soldado mines, was bought by ENAMI from PeƱarroya a year after the nationalisation and was sold six years late (at a handsome profit) to Exxon Minerals[1]. Mantos Blancos, owned at that time by the Peruvian Mauricio Hochschild group[2], was not nationalised, nor were the smaller mines like Sagasca, Lo Aguirre and the Tierra Amarilla operations.