The results are from first stage reconnaissance drilling at its most advanced project.
Twelve holes were completed, five of which were reported last November. Today's assays are from seven holes.
"We are happy with the results at El Petate, said Tawn Albinson, the president of Prospero Silver.
He added that in particular three holes had highlighted "interesting" grades over intervals of up to 24.9 meters downhole, although with unknown strike extent, indicating prospective deeper targets for a follow-up program.
The drilling of Petate is being carried out as part of the firm's campaign evaluation financed by strategic partner Fortuna Silver Mines over three of Prospero's projects.
When Prospero has completed drilling three projects, Fortuna have the right to select one for a joint venture.
Highlight results today included an interval of 24.9m with 0.76 g/t (grams per ton) gold and 22.4 g/t silver.
Another highlight was 3.9m at 1.18 g/t gold and 3.71 g/t silver.
The company said it was keen, like Fortuna, to drill as many of Prospero's projects as possible, hence it plans to mobilise onto the next target - Pachuca SE - as soon as January (this month).
The Pachuca SE target lies about 20km southeast of the Vizcaina vein, one of the largest silver-rich epithermal veins in the world, it added.
Prospero shares in Toronto added 4.76% to C$0.11.