San Rafael is an underground mine which began operations in October 1977 and currently produces 12% of the world’s Tin. It also generates the highest income in the Puno region and is the main driving force behind the economic development.

It treats cassiterite ore (SNO2) at a rate of 2,830 Metric Tons/Day, with average mill head grade of 2.65% Sn and recovers 89%. They make use of two methods of concentration: Gravimetric treatment by inverse flotation and direct flotation of cassiterite.

The application of the mining exploitation method «Sub Level Stoping» with the variant Large Blast Hole (LBH) for this type of mine composed of hard wall and competent rock.