Resumen de Prehistoric mining
Prehistoric copper mining in the north-east of the Iberian Peninsula continues the previous work on copper mining by the editors and main authors N. Rafel Fontanals, M.A. Hunt Ortiz, I. Soriano and S. Delgado-Raack. The site La Turquesa, a deposit mainly of Gossan type (iron cap), belongs to the same fault zone and mining basin as the already published Solano del Bepo (Rafel Fontanals et al. 2017). Mining of copper and lead (galena) at the site cannot certainly be traced back into prehistory, let alone to the Neolithic, and the earliest radiometric dates point to mining beginning before the early Middle Ages. The typo-chronology of mining tools is inconclusive, as is usual at these sites, and as the reader may infer from the comprehensive 80-page catalogue of hammerstones and picks. In his archaeo-metallurgical chapter, Montero Ruiz concludes convincingly that, currently, the most reliable date for mining at La Turquesa is in the Copper Age or the Early Bronze Age: the isotope signature of the mine's ore seems to accord with isotope ratios measured in a handful of artefacts from that period. The geology and mineralogy of the deposit is instructively summarised, adding archaeologically relevant information on visibility, accessibility and workability (with A. Andreazini and J.C. Melgarejo as co-authors). Traces of prehistoric opencast copper mining in small and irregular shafts have been heavily damaged by nineteenth- or twentieth-century mining of turquoise and variscite (with accessory chalcopyrite and malachite). The archaeological documentation of shafts and galleries from recent and pre-industrial times is cursory and does not fully attend to the three-dimensionality of the deposit. The use of more up-to-date measurement technology would have offered a clearer understanding of the site in its excavation, analysis and publication. No traces of tools were documented, making it impossible to combine the mineralogy of the deposit with the practical mining work. Without any quantitative information on heap material the mine's productivity cannot be estimated. The discovery of evidence for fire-setting using thermoluminescence (detailed in the chapter by A.L. Rodrigues et al.) seemed a promising test for archaeological hypotheses. Unfortunately, the palynological sediment sample gives a terminus ante quem of the seventh or eighth century AD (chapter by S. Pérez Díaz and J.A. López Sáez). Alongside unpublished indeterminate pottery, 117 mining tools are described in detail (including use-wear, lithology and surface types). Comparison with material from nearby Solana del Bepo (Rafel Fontanals et al. 2017) reveals that the artefacts from La Turquesa are less sophisticated and more opportunistic: mainly hammerstones modified during use or simple picks, sometimes with a picked groove that indicates hafting. Delgado-Raack argues convincingly that the tools were used in a context of direct extraction, for crushing the rock as well as for fragment-crushing copper ore at the site.
