Freziér describes how the Indigenous workers are employed to mold silver parcels 8 times a day and how they stir the water mixtures thoroughly with their feet to separate the silver. He also describes how, prior to the conquest, the Andeans would melt the lead from the ore using furnaces rather than separating the silver from it using Quicksilver as the Spanish had introduced. These furnaces were powered using wood and dung. Frézier is enraptured by these secret histories that Peruvians speak of and how the Indigenous people had come to use such methods drawn from the earth itself. Frézier does not express as much interest in the pre-conquest gold mining practices of Chile, as he merely remarks that they were similar to those already known in Germany.
The exhalations from the mines are, according to Freziér, dangerous. He writes that the indigenous miners are obliged to regularly drink Mate, an herb from Paraguay, to moisten their breaths and prevent them from being numbed or having immense body pains. Frézier also mentions the Indigenous use of coca chewing herbs in Chile and Peru both to aid in further protection against the ill inducing air of the mines, and within secular life. Frézier writes that the Indigenous people "apply it to too many several Uses, most of them bad, that the Spaniards generally believe it has none of those Effects [in protecting against the illnesses of the mines], but by virtue of a Compact the Indians have with the Devil. For this Reason, the Use of it is prohibited in the Northern Part of Peru; and in the South, it is allowed in regard to those who work in the Mines and cannot subsist without it.” Frézier writes that the Spanish resentment of the Indigenous people chewing the herbs is so strong that the inquisition persecutes those who go against their prohibitions.