After being in use for three centuries in the Peruvian silver mining, tha amalgamation with mercury method was replaced in 1890's. This took place when the main world producers had been using a different method for over half a century. This delay was due to several factors: there was a mercury mine in Peru which, though not in use, was always expected to be reactivated; there was no cash availability for a main technical change; and the legislation that had been in force for a long period did not foster large-scale mining. When some of these conditions changed after 1885, there was a battle over technical change fought by the Engineer School of Mines (Escuela de Ingenieros) on one part, and foreign enterprises, which both defended different methods. The latter won the battle when the railways were finished in early 20th Century. The winning proposal was more efficient in technical terms but had less redistributive effects at the regional and national economic level.