Operator: First Majestic
Location: Mexico
Term of Stream: Life of Mine
Stream Parameters: 25% of gold production plus an additional amount of gold equal to 25% of silver production converted to gold at a fixed gold to silver exchange ratio of 70:1
Upfront Consideration:  US$220M
Cost Quartile: 1st
Primary Metal: Gold

Project Overview

The San Dimas mine (“San Dimas”) is owned and operated by First Majestic Silver Corp. (“First Majestic”). The mine is a low-cost producer of gold and silver and has been in continuous production for well over 100 years. The San Dimas gold-silver deposit, located in the San Dimas district on the border of Durango and Sinaloa states, is one of the most significant precious metal deposits in Mexico. The district is comprised of over 100 epithermal bonanza type mineralized gold-silver veins. The veins widths vary from less than one centimetre to over 15 metres, but average approximately 2 metres. Veins have been followed underground from a few metres in strike-length to more than 2 kilometres.

Mineralization is typical of epithermal vein structures with banded and drussy textures. Three major stages of veining have been recognized in the district, each containing variable amounts of mineralization. The second stage produced the majority of the ore deposits, which included three sub-stages characterized by distinct mineral assemblages, quartz-chlorite-adularia, quartz-rhodonite, and quartz-calcite. Sulphide minerals include pyrite, sphalerite, chalcopyrite and galena as well as lesser amounts of argentite, polybasite, stromeyerite, native silver and lectrum.

Over the substantial mine life to date, the operating team at San Dimas has demonstrated a strong track-record of converting resources into reserves and the mine continues to exhibit excellent potential exploration upside. Primero has stated that it believes that it can continue to expand reserves by focusing new drilling programs on areas with significant exploration potential, such as the Sinaloa Graben block, where exploration results confirm mineralization of higher grades and in wider veins than the existing reserves.

The San Dimas district has experienced a long mining history dating back to 1757 with the first cyanide mill being built in Mexico at Tayoltita in 1904. Historical production from the district is estimated at 582 million ounces of silver and 11 million ounces of gold, affirming it as a world class epithermal mining province. The mines at San Dimas are underground operations using primarily mechanized cut-and-fill and long-hole stoping mining methods. Once milling, cyanidation, precipitation, and smelting occur at the San Dimas mill located near the town of Tayoltita, doré bars are poured and then transported to refineries in Mexico and the United States.

Precious Metal Purchase Agreement

On May 10, 2018, in connection with the First Majestic acquisition of all the common shares of Primero, Wheaton agreed to terminate the San Dimas silver purchase agreement with Primero and enter in to the First Majestic precious metal purchase agreement (PMPA).
  • First Majestic PMPA Terms:
  • 25% of gold production plus an additional amount of gold equal to 25% of silver production converted to gold at a fixed gold to silver exchange ratio of 70:1 from San Dimas, with provisions to adjust the gold to silver ratio if the average gold to silver ratio moves above or below 90:1 or 50:1, respectively, for a period of six months

For each ounce of gold delivered, Wheaton International will pay to First Majestic a production payment equal to the lesser of US$600/oz, subject to a 1% annual inflationary adjustment, and the prevailing market price

More Information

Click here to view First Majestic’s San Dimas video.
Click here or visit to view the April 2014 San Dimas Technical Report.
For more information about the San Dimas mine, please visit First Majestic's website at
Cost quartile information is sourced from Wood Mackenzie by-product cost curves for gold, zinc/lead, copper, nickel, and silver mines.