Operating Practices, Plant Design and Logistics to Double Silver Production at Fresnillo Operations in Mexico
Rodolfo Espinosa Gomez
Fresnillo Plc (Fresnillo) is a Mexican Company owned by the “BAL Group”, focused on the production of gold and silver. It was established in 2008, initially consisting of three companies, Minera Fresnillo, Minera Mexicana La Ciénega and Minera Penmont and had an annual production of 52 million silver equivalent ounces.
By 2017, Fresnillo was producing 113 million silver equivalent ounces, by establishing two new companies:
- Minera Saucito that currently has two flotation plants and a pyrite leaching plant utilising a Dynamic Leaching / Merrill Crowe processes, and
- Minera San Julian that currently has two processing plants, one using flotation and the second one using the Dynamic Leaching / Merrill Crowe processes.
Another important contribution to the doubling of production was the development of two new gold and silver Dynamic Leaching / Merrill Crowe Plants.
The paper describes some of the operating practices, plant design and logistics required to double the silver equivalent ounces production. New technologies were used, such as Derrick Screens that in some processing plants work together with hydrocyclones in the primary grinding circuits, flotation cells using the latest technology developments and vertical stirred mills that regrind to about 10 µm (P80 size).
Fresnillo has also achieved important environmental developments. The four plants that operate in the Fresnillo District, in the State of Zacatecas, operate using treated wastewater from the City of Fresnillo.
Currently the company is developing another wastewater treatment plant to provide the fresh water requirements for two new projects currently being developed.