Active filters :
Discard Filter

Perth Branch – Roving Report – September 2019

Back after a short hiatus, Richard Dewhirst's popular Roving Report returns with stories and historical tales from the global mining community.

By Richard F. Dewhirst FAusIMM(CP)

Dear Member,

With apologies for a long absence, I offer this brief piece on my recent first visit to Mexico and some snippets about its rich, colourful and historic mining industry which I hope might be of interest to our readers.

It came about through a brief Independent Project Review for ArcelorMittal – the world’s biggest steel producer – to assess some planned expansions of their iron ore mining operations in Mexico. It also gave me the opportunity to learn a bit about some of the history of mining in general in that country and specifically the genesis and importance of steelmaking, which can be traced back to the early 19th Century. This was when the Guadalupe foundry adopted blast furnace technology and the industry further grew in the latter part of that century when Siemens machinery was introduced. In 1900, the Monterrey Iron & Steel Foundry Co. was established and other large-scale foundries and mills grew up in the ‘30s and ‘50s, several incorporating technological innovations and introducing new products. In the 1970’s the industry was effectively nationalised, but re-privatised in the 1990’s. ArcelorMittal itself has been busy growing its Mexican operations through acquisitions since that time.

ArcelorMittal’s mines feed their primary steelmaking operations at the Michoacán State deepwater port city of Lázaro Cárdenas named in tribute after Mexican President (1934-40) Lázaro Cárdenas del Río who came from Michoacán. The plant produces products for the auto sector and construction, energy and home appliance industries.

And now to a brief history of silver and gold for which Mexico is more commonly known for. The history of commercial mining dates back over 500 years, while pre-Colombian populations held gold, silver and other metals and minerals in high regard.

Like much of “New Spain”, Mexico was seen by the Spanish Empire primarily as a supplier of wealth to Iberia. This came from its huge silver and mercury mines. Large strikes in Zacatecas and Guanajuato to the north of Mexico City created important centres of silver extraction, in particular San Luis Potosí – named after the (in)famous Potosí silver mine in Perú. In early days, with high silver grades, recovery was primarily by smelting ores. Later on, most of the extraction of silver came through the patio process. How this came about sounds like something from an Alchemy textbook. One Bartolomé de Medina – a successful Spanish merchant who tried to address the decline in silver grades and higher production costs in the mid-1500’s – met an unknown German known only as “Maestro Lorenzo”.

This “Master” told him that silver could be extracted from ground ores using mercury, which was abundant and found associated with the silver deposits as Cinnabar, and a brine solution. Medina took this a step further and added “magistral” (which translates as “masterly”, but is in fact a copper sulphate) which catalyzed the amalgamation reaction and for which he obtained a patent from the Viceroy of New Spain.

He died a wealthy man, but heaven only knows how many miners turned into “Mad Hatters” as they succumbed to mercury poisoning.The silver mines surrounding Real del Monte sourced over 50% of the silver produced during 300 years of Spanish rule. However, in the early 1800’s most were in poor condition. A group of English investors founded “The Company of the Gentlemen Adventurers in the Mines of Real del Monte” (sounds like an Indiana Jones adventure) and recruited miners and engineers from Cornwall. Many never made it, succumbing to yellow fever en route. Those that did eventually get there took over a year, an arduous journey as they and their mules dragged their famous Cornish steam engines through marshes and rainforests so as to have the means to drain water from flooded mines and recommission them.

Image: Stocks in Pachuca Mining Companies in the Museo de Mineria

Nearby Pachuca – which for me evokes memories of those eponymous tall leaching tanks on gold and uranium plants – was another site of mining “boom”. Cornish Miners (“Cousin Jacks”) moved there in the 18th Century to escape lack of work in their home county – as they did to many mining centres across the globe, including Bendigo and South Australia – bringing with them their knowledge of hardrock mining and making good the saying that “a mine is a hole anywhere in the world with at least one Cornishman at the bottom of it”. The Cornish introduced football to Mexico, founding the Pachuca Athletic Club, rugby, and of course the cornish pastie – Cornwall’s answer to the empanada – to Pachuca and to Mexico.

For those who want to find out more and delve into some interesting photos of past times, the following presentation may be of interest:

Royal Mines of Zacualpan Mexico – 500 Years of Mining History

Saludos cordiales from Santiago, Richard F. Dewhirst FAusIMM(CP)

Download the Report

Related News


Perth Branch - Digital Tech Talk: Practical Applications of Machine Learning Across Mining and Exploration

Participants will gain an understanding of the current state of play of machine le...


Perth Branch - Digital Tech Talk: Practical Applications of Machine Learning Across Mining and Exploration

Participants will gain an understanding of the current state of play of machine le...


Watch the Perth Branch March Tech Talk

Turning a Nickel Exploration Play Into a VMS Opportunity