Orosur contols over 570,000 hectares in Uruguay and ~65,000 hectares of mining and exploration tenements in the San Gregorio vicinity

The mine historically produced through a series of open pits, and in 2011 commenced development of Uruguay’s first underground gold mine, the presently producing Arenal Deeps mine. Project infrastructure, access, power and communications are good with access by paved road, grid and cellular connection and a local workforce in Minas de Corrales, a town approximately 5km from the mine.



  • The Spanish first mined for gold in the region during the 1770’s.
  • British operated gold mines in the Minas de Corrales area from 1910 to 1914, utilising a hydro-electric plant constructed by the French in the 1870’s to support gold mining in the region. The French also built a treatment plant at the same site on the Rio Cuñapiru and constructed an aerial tramway to transport ore to the plant. Total production to 1914 is estimated at 90,000 oz of gold.
  • The San Gregorio deposit was held by American Resource Corporation prior to Rea Gold Inc. (“Rea”) acquiring the project. Rea commissioned Minproc to construct the process plant, which was in operation by January 1997, treating ore from the main San Gregorio open pit.
  • Rea experienced operational difficulties at its North American operations and sold the SGGP to Crystallex International Corporation Inc. (“Crystallex”) in 1998. Crystallex held the property for five years. They focused their work on the expansion of the San Gregorio and Santa Teresa deposits because they were very limited in their land tenement holdings with Orosur holding all the surrounding area.
  • Crystallex partially drilled the mineralization on the San Gregorio eastern extension during their tenure.
  • Orosur has been operating in Uruguay since 1996, and has compiled an extensive country wide database utilising information from previous explorers. Orosur staked approximately 65,000 hectares of exploration ground adjacent to the Crystallex mining operation and along the strike of the Rivera Shear.
  • In 2003, Orosur acquired the mineral assets of Crystallex in Uruguay, including the San Gregorio open pit mines and the ore treatment plant at Minas de Corrales. Since that time, Orosur has been undertaking extensive drilling activities and has delineated multiple sources of mill feed from the San Gregorio, Ombú, Zapucay, Arenal, Castrillón, Crucera and Sobresaliente deposits.
  • Over the past 2 years, Orosur has mined the Santa Teresa, Sobresaliente, Crucera, Vaca Muerta and Zapucay-Argentinita open pits and the Arenal underground.
  • Orosur previously mined ore from the Arenal open pit, the main San Gregorio open pit and extensions of the mineralization along strike to the east and west.
  • Orosur owns it fleet of open pit and underground mining equipment and CIL processing plant capable of treating 1.5 – 1.6Mtpa at average recoveries of over 93%


  • Drilling to date of [6,800] holes totalling [405,000]m
  • Exploration by Previous Owners
  • Regional airborne geophysical surveys were flown over the area by Rea in 1996, resulting in aeromagnetic and radiometric data was acquired by Orosur when it purchased the Crystallex subsidiary that operated San Gregorio and performed regional exploration.
  • The surveys were carried out at a line spacing of 200m, and the data are semi-regional in nature.
  • A number of soil sampling grids have been established at various locations along the San Gregorio Fault Shear (“SGFS”) by previous operators.
  • Crystallex partially drilled the San Gregorio eastern extension mineralization.
  • Exploration by Orosur
  • Orosur has undertaken a number of soil sampling programs along the SGFS in an effort to infill and confirm previous soil anomalies and to test other structural and geophysical targets.
  • The current exploration program in the project area is comprised of multi-geoscientific disciplines with focus on quality control and quality assurance to maintain best industry standards.
  • An increase of in-house exploration expertise is being complemented with external consulting experts.
  • Geochemical investigation of soils and outcrops, field mapping, structural mapping on regional and local bases, trenching, RC drilling and Diamond drilling.
  • Orosur personnel conduct all geochemical investigations, geological mapping and trenching. Structural interpretation from aerial photography has been performed and structural appraisal on the ground has been conducted.
  • Exploration and resource drilling by Orosur is a combination of RC and diamond drilling.
  • Orosur has a strong track record of reserve replacement and resource conversion