History of the Gold Sands District
Rio Marañón, which for millions of years has been feeding sand, gravel and gold to the property controlled by Constitution Mining, is by legend the source of the gold paid to the conquistador Pizarro to ransom Atahualpa, last emperor of the Incas. Small-scale, generally primitive, mining of the Gold Sands has continued since that transaction. In the modern era, exploration and development efforts include:
1940s. A German company operated a 10 cubic meter dragline 10 kilometers (6 miles) downstream from Saramiriza (now the selected site for Constitution Mining’s logistics and administration base). Their departure was motivated by World War II.
1979 to 1980. Cia Panasa (a local Peruvian company) recovered gold from the El Banco Island, 14 kilometers (8.7 miles) northwest from Saramiriza. Heavy earth moving equipment was used with positive results, but was vulnerable to high flood levels that are experienced in the Saramiriza area.
1983. A group of Canadians entrepreneurs operated a small suction dredger 15 kilometers (9.3 miles) south of Saramiriza. They abandoned the project under technical and legal pressure caused by its proximity to an oil pipeline.
1989. Mutiferros SA, a Brazilian company, introduced four suction dredgers to the Gold Sands, but their design eventually proved to be ill-suited for the deposit.
1991 Geologists Montoya and Medina from Centromin Perú S.A. carried out reconnaissance bulk sampling of alluvial gravels along 80 kilometers of the Marañón River. The average grade of the 26 placer samples was 253 mg/m3, ranging from 100 to 400 mg/m3, with the highest grades occurring in the downstream half of the river sampling i.e. + 40 kilometers below the Manseriche Gorge.
1990 to 1992. Cia Monica de Iquitos drilled off a 10 square kilometer (6 square mile) lease in Manseriche Camp and proved-up grades of 295 milligrams per cubic meter to a depth of 32 meters (105 feet). They were unable to finance further development and abandoned their lease, which in 1995 was picked-up by Lomas del Marañón SA.
1994. Matsag Minerals, a company controlled by Glencor of Switzerland, acquired leases near Puerto Elisa 12 kilometers (7.2 miles) down the river from Saramiriza) covering a large abandoned river meander. They used a 3-ft bucket line dredger as a bulk sampling tool but did no drilling. Their leases were subsequently acquired by Lomas del Marañón.
1995 to 1997. Lomas del Marañón installed a camp and operated a floating backhoe washing plant. Their poorly designed system of sluices yielded low recoveries.
1998. IHC Meerwede of Holland conducted preliminary metallurgical tests and engineering studies.
1999 to 2000. Private Brazilian interests, under the technical direction of alluvial engineer Peter Rich, demonstrated the viability of recovering gold from the sands and gravels in the Saramiriza area using bucket line dredgers, and unsuccessfully sought project financing from Canada at a time of low gold prices.
2006 Consultant James Prudden, on behalf of Aurum Corporation, carried out reconnaissance sampling of placer deposits along the Marañón River for 100 kilometers downstream from the Manseriche Gorge. Twenty four samples collected averaged 169.2 mg/m3 with the samples from the lower 45 kilometers averaging 268.9 mg/m3. Prudden concluded that “this 100 kilometer length of river would be considered an extremely large placer district that requires systematic evaluation”.
2007 to 2008. Temasek Investments Inc., following Peter Rich’s earlier recommendations, consolidated the project area by staking additional ground in Manseriche Camp and in two other, nearby camps.
2008. Constitution Mining acquired options on leases in Manseriche and nearby camps, thereby gaining control of 60% of all leases in the area and becoming the largest operator of claims in Manseriche Camp.
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