Wheaton Precious Metals Corp.

Sampling, Analysis and Data Verification

Exploration

Sample preparation details prior to 2002 are unknown. During 2002 – 2003, sample preparation was conducted by Lakefield / GEOSOL laboratory at a local facility built at the Salobo mine site.

During the 1978 campaign, samples were assayed at the Docegeo laboratory in Belém, Pará, and at the SUTEC laboratory in Santa Luzia, Minas Gerais. Copper was assayed on 0.5 g aliquots by multi-acid digestion and atomic absorption spectroscopy (AAS). Iron, molybdenum, and silver were also determined using this method. Gold was assayed by aqua regia leaching, with solvent extraction (MIBX) and AAS determination.

During the 1986 campaign, CVRD assayed the samples at the Docegeo laboratory in Belém and at the pilot plant laboratory on the mine site, using the same analytical methods as in the previous campaign.

During the 1993 campaign, SML used the Mineração Morro Velho (MMV) laboratory. Copper was again assayed with multi-acid digestion and AAS reading on 0.5 g aliquots (0.002% detection limit), and gold was determined using the fire-assay method with gravimetric finish on 100 g aliquots (0.05 g/t detection limit). In addition, samples were assayed for sulphur and carbon by LECO, and fluorine by alkaline fusion with sodium carbonate and potassium nitrate, followed byion-selective electrode determination. SMSA used the same analytical procedures during the 1997 campaign.

In the early stages of the exploration program platinum, palladium, nickel, molybdenum and uranium were also analyzed; however, these elements were later excluded from the analytical package.

The infill and deep drilling programs that began in 2010 are using sample preparation procedures similar to the 2002 – 2003 campaign. Sample preparation was being done at the Salobo mine laboratory but was switched to ALS, Vespasiano, Minas Gerais, Brazil in December 2018 in order to advance the backlog of pending samples. In September 2021 the sample preparation was moved to ALS, Parauapebas, Para, Brazil. Since 2017, samples are being analyzed at ALS, Lima, Peru as the primary lab and since March 2018 SGS Geosol, Belo Horizonte, Minas Gerais, Brazil has been used as the check assay laboratory.