It named Trigusa, with the contractor currently active on site having recently completed all civil works related to the construction of the gold recovery plant, solution ponds and heap leach pad.
"Our Mexican operations team has a long and positive history with Trigusa dating back to their involvement with the construction and operations at the El Castillo mine (Castle Gold)," CEO Darren Koningen said.
"Given the logistical challenges surrounding the construction of a new mine during the COVID-19 pandemic we have witnessed firsthand, and in the toughest of environments, the commitment and execution of Trigusa."
Minera Alamos has said it was built around its operating team which brought three mines into production in Mexico over the past 13 years.
It has not completed a feasibility study on Santana.
The fully-funded C$10-12 million heap leach operation was expected to start gold production in the second quarter, the company said in February presentation.
Minera Alamos has two other projects in Mexico - the recently acquired Cerro de Oro which it said represented a near-term development opportunity, and the La Fortuna project, now set to be third cab off the rank.
Minera Alamos shares (TSXV: MAI) have spanned 22-78c over the past year and closed up more than 10% yesterday to 65c, valuing it about $287 million (US$228 million).