Identifying metallurgical practices at a colonial silver refinery in Puno, Peru, using portable X-Ray fluorescence spectroscopy (pXRF)

•Field pXRF analyses were carried out on surface soils from a colonial silver refinery.•Metallurgical activity areas were identified.•The patio process with mercury amalgamation was confirmed at the site.•Local Andean adaptations to the patio process were also confirmed.•Analysis of field pXRF data revealed phosphorus (P) was affected by high-altitude. This study presents the results of in situ portable X-ray fluorescence (pXRF) analyses of surface soils at the site of Trapiche Itapalluni, a Spanish colonial silver refinery located 15 km southwest of Puno, Peru in the western Lake Titicaca Basin (4000 masl). Although the benefits of pXRF analysis are well known, such as its wide availability and rapid, non-destructive nature, there has been little applicability of this technique at colonial metallurgical sites in the high-altitude Andes. The results of our analysis confirmed the introduction of the patio process technique of silver refining from Mexico to the Puno Bay, and further clarified areas of intense metallurgical production, including local Andean adaptations. This study highlights the advantages of in situ pXRF analysis of surface soils at industrial archaeology sites, especially in marginal and high-altitude environments such as the southern Andes.