Sierra Gorda Molybdenum Plant

Sierra Gorda Sociedad Contractual Minera | Chile | 2012–2013

900 ppm

(Moly ore feed grade) higher than industry average in first 4 years

110 ktpd

of ore throughput for Phase I

790 ktpa

of collective concentrate

190 ktpd

of ore throughput for Phase 2


  • Ensure the mine-and-concentrator activity met a very steep ramp-up curve and a very aggressive engineering and construction schedule.
  • Adjust for molybdenum feed grade of 900 ppm initially and lower grades in later years of operation.
  • In its first four years, the 110-ktpd-ore-throughput copper-and-molybdenum concentrator will produce 450 ktpa of collective concentrate, of which 7% is molybdenum concentrate.
  • For the remainder of its 22-year life, process 190 ktpd of ore, generating 790 ktpa of collective concentrate with 1.5% molybdenum concentrate.


  • Provided all detailed engineering to enable the molybdenum flotation plant to integrate smoothly into the main concentrator plant.
  • Ensured design is flexible enough to operate from year one to the end of the mine lifespan.
  • Only minor piping changes are needed to process different throughputs from main concentrator.
  • Integrated pre-commissioning and commissioning data with existing schedules to demonstrate progress, identify potential risks, and advise on developments to minimize start-up delays.


  • In the first five years, the very high-grade molybdenum concentrate will produce significant revenue.
  • Awarded additional work to support ongoing field engineering for the moly plant, pre-commissioning, commissioning, and operational readiness for entire Cu-Mo concentrator.
  • Supported further development of detailed schedules and checklists, enabling efficient pre-commissioning turnover and execution of the commissioning work.
  • Assisted Sierra Gorda to audit spares, develop health-and-safety standards and isolation procedures, and facilitate overall plant operational-readiness activities.

”Thanks to Hatch we will have in Chile the largest molybdenum plant, with the best technology and a high standard.”

Cecilia Gonzalez | Process Manager, Sierra Gorda SCM

Project numbers

110 ktpd ore throughput, first 4 years
190 ktpd ore throughput (remainder 22 years)
20-member site team

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