Our Projects

Superior Lake



Superior Lake Resources
Thunder Bay, Canada

Superior Lake Resources’ Superior Lake Zinc Project is located approximately 200 km east of Thunder Bay in the province of Ontario, Canada. The Project covers 175km2 and consists of two deposits – Winston Lake and Pick Lake.

Primero was engaged in 2019 to execute the bankable feasibility study for re-development.


Primero completed a bankable feasibility study for the re-development of the underground Zinc mine, process plant, site infrastructure and, licensing and permitting. All design elements were made suitable for cold climates. Historical test work and operating data were largely relied upon for process design. Historical power supply and building foundations were used as much as possible. Tight control over site water management and dust emission was included in the design to satisfy stakeholder requirements.

  • Study deliverables were those suitable for a class 3 study:
  • Process design including historical test work review.
  • Test work management.
  • PDC, MB and PFDs.
  • Plant design suitable to support the formation of process plant and project CAPEX and OPEX, including mechanical, electrical, civil, structural and associated drafting.
  • Procurement and project execution planning and documentation.
  • Study management for both the process plant and deliverables from external consultants for site-wide infrastructure and underground mine redevelopment.

Process Description

The Superior Lake process plant is designed for a nominal 44tph of underground ore with high zinc grades and lower quantities of copper. The ore is crushed to P80 80mm via a primary crushing circuit and then conveyed to a SAG mill for milling to a target of P80 75µm. The copper circuit consists of rougher flotation, copper regrind circuit and two stages of cleaner flotation before dewatering via thickener and filter press. Zinc is recovered from the copper circuit tail via rougher-scavenger flotation, zinc regrind circuit and three stages of cleaner flotation before dewatering via thickener and filter press. Zinc and copper concentrates are each loaded into containers that are sealed before removal from the process plant building for dispatch. The tailings are thickened and pumped to the TSF or fed to the paste plant before being pumped underground. Water treatment is included for the zinc flotation process water and any water requiring discharge from the process plant.