Geology and Mineralization

Peru produces 5.6 million ounces of gold per year, nearly half of it from Newmont’s Yanacocha Mine.

At other sites, alluvial production has been growing, from 200,000 ounces in 1991 to a current rate over 500,000 ounces per year. Much of that comes from Peru’s four major alluvial fields -- Iquitos, Ucayali, Madre de Dios and Marañón-Santiago, where Constitution Mining’s interests are located.

Large-scale alluvial gold deposits tend to form where folded mountains abut flatlands. A gold deposit may accumulate on the flatlands if (1) gold is present in the adjoining mountains and (2) an energetic river system runs through the mountains and carries off gold-bearing sand and gravel. When the river system reaches the flatlands, the speed of the water drops, and the sand, gravel and gold settle out.

In the case of the Manseriche Camp, the Marañón and Santiago rivers rise from peak elevations of 2,900 meters (9,500 feet) and 3,500 meters (11,483 feet), respectively. As they travel 900 kilometers (560 miles) through the Andes, they are fed by the Marañón-Santiago drainage basin, which is home to some of the world’s largest gold deposits and gold mining operations (including Yanacocha, Cerro Corona and Fruta del Norte). Near the base of the Andes, at an elevation of just 170 meters (557 feet), the rivers converge at the Manseriche Gorge. Then they pour onto a broad flatland and deposit their sedimentary load.

Geological Model

The geological model for the Marañón basin consists of an extensive braided fluvial system occupying the axis of a shallow east-plunging syncline thus creating a yoked basin which is the most favorable structural setting for sediment reworking. This massive river complex has migrated northward through geological time, creating numerous abandoned meander systems and braided stream capture situations providing tremendous volumes of reworked gold-bearing sediments. The prevailing gold morphology allows gold to migrated considerably further in this fluvial environment than in classical alluvial systems. Consequently, gold can be found in the sediments of the Rio Marañón for over 130 kilometers below the Manseriche Gorge, explaining the metal’s widespread distribution throughout the basin where Constitution Mining’s properties are located.

Learn the history of the Gold Sands, Click Here.