Obsidian quarry workshops at Zináparo-Prieto in the state of Michocan in western Mexico were investigated comprehensively by Veronique Darras (1991;1999). Darras undertook excavation as well as systematic survey of vicinity of the substantial quarry area that was used most intensively during the Classic to Post-classic transition (A.D. 850-1000). She documented mines and workshops, as well as associated residential structures and public buildings, in an inventory of 45 sites in the region.

Darras describes mine shafts and open-air quarry pits that parallel obsidian procurement methods elsewhere in Mesoamerica. The mine shafts (Darras 1999: 72-80), are over 25m in depth and include support pillars as well as evidence of torch lighting and ventilation shafts, can be compared with Classic and Post-classic period mining methods used at other Mexican quarries that include the Sierra de las Navajas (Pachuca) source in Hidalgo (Pastrana 1998), and the Orizaba mines (Cobean and Stocker 2002). Open-pit quarry depressions are reported by Darras at Zináparo-Prieto that measure between 10-15m in diameter, with a few larger than 15m in diameter. Quarry depressions with an encircling debris mound were described by Healan (1997) at the Ucareo source, also in Michocan, as "dough-nut quarries".

The lithic analysis approach used by Darras, citing the tradition of Tixier (1980), addresses the abundance of material (the typical problem with quarry research) by employing two levels analysis (Darras 1999: 108-115). The first measures abundance using a relatively expedient typological classification based on material quality, technical class, reduction stage, and relative size and form of artifact. The second level of analysis, conducted only on a representative samples, consists of a techno-morphological analysis of flakes including a detailed study of platform characteristics and fracture and termination types.

Darras finds no evidence of pressure flaking or prismatic blade technology, a situation that makes this workshop analysis to be more comparable to reduction sequences elsewhere outside of Mesoamerica where prismatic blade production also did not occur, such as obsidian production the south-central Andes. Darras finds that percussion industries follow two contemporaneous sequences: one that uses "cada plana" (plane-face) cores, and the other that uses conical cores, each sequence meticulously outlined. These twin industries, and the lack of prismatic blade production, are unusual in the region and Darras suggests that this is due to a lack of regional political control during this stage.

Darras succeeds in integrating household archaeology with her workshop studies, and as revealed by comparison with obsidian consumption in an associated village, Darras documents substantially more obsidian production than appears to have been used locally. However, she does not extend her analysis to the immediate region beyond villages adjacent to the quarry areas, leaving a disjunction between reduction evidence from the immediate quarry workshops and the larger pattern of obsidian artifacts radiating into the region. Darras' study is one of the most thorough workshop investigations to date, and her work provided a valuable model for the current Upper Colca project research because in the manner that test excavations were used to connect quarry evidence with initial reduction trajectories at associated workshops.