OREAS 274

OREAS 274 was prepared from a blend of Carlin-style heap leach material sourced from the Goldstrike operation in northeastern Nevada (operated by Nevada Gold Mines – Barrick), combined with a multi-component synthetic diluent simulating siliceous shale and carbonate host lithologies common to the Carlin Trend.

Gold mineralisation in the source material occurs as fine disseminations within siliceous, carbonaceous, and sulphidic sedimentary rocks, representative of classic Carlin-style deposits. The synthetic diluent, comprising limestone, shale, dolomite, graphite, silica, and black slate, was carefully proportioned to match the matrix characteristics of exploration and mine samples from this deposit type.

OREAS 274 has been characterized for gold, majors and traces using the following methods:

• Gold by fire assay with AAS, ICP-OES or ICP-MS finish
• Full ICP-OES and ICP-MS elemental suites by 4-acid (HNO3-HF-HClO4-HCl) digestion
• Full ICP-OES and ICP-MS elemental suites by aqua regia digestion
• Total Carbon and Sulphur with infrared combustion analysis

Certified values for applicable analytes are operationally defined for each method, with results under OREAS ISO 17034 scope of accreditation.