Note 3 — Chapter I
Reading edition
At Huallianca, Hualliay, and several other parts of the rich department of Junin, smelting is used for the extraction of silver: but in Cerro Pasco smelting is little practised. In the district of Yauricocha, and especially in the great or King’s mine, the ores are found to contain a considerable portion of the sulphuret of lead; and, also, of the sulphurets of copper, of iron, and of silver.
Such is the quantity of sulphuric acid distributed among the mines of Cerro Pasco, which are placed among limestone hills, that the water which they contain is observed to corrode the iron machinery exposed to its continued action.