The copper property of Marcopper Mining Corporation is situated on the west slope of Mt. Tapian, Barrio Labo, Sta. Cruz, Marinduque. It is within 122°53’40" to 122°53’53" east longitude and 13°23'00" to 13°25’50" north latitude.

Mt. Tapian is a prominent peakin the region with an elevation of 698 meters above mean sea level. The site of the copper deposit includes the rugged, precipitous and hilly sections west of Mt. Tapian.

The main drainage system in the area, the Bol and Maculapait rivers, flow westward. All streams empty into the Boac River which is the master drainage in the province.