Dolores is an open-pit and underground silver-gold mine owned and operated by Compañía Minera Dolores S.A. de C.V., a wholly owned subsidiary of Pan American Silver Corporation (“Pan American”). Dolores is located in Chihuahua state, Mexico, approximately 240 kilometers west of the city of Chihuahua.

Construction of the mine began at the end of 2006, the first doré was produced in November 2008, and commercial production began in May 2009. The processing facilities include a crushing plant, conveying and stacking facilities, leach pads, solution ponds, and Merrill-Crowe and refining facilities. Pan American completed an expansion of the Dolores mine in 2017 that featured a pulp agglomeration plant to process high-grade ore from a new underground mine, together with the high-grade portion of the ore from the open-pit mine.

Mining at Dolores has been ongoing since 2008 using conventional open-pit methods with excavators, shovels, loaders, and haul trucks. Underground mining of the deposit by long-hole open-stoping methods occurred between 2017 and 2022. Ore is crushed and conveyed to the heap leach pads at a nominal rate of 16,200 tonnes per day. Mining and stacking on the heap are expected to conclude in the third quarter of 2024, with the property entering into its reclamation phase while residual leaching continues for a few years thereafter.