Harte Gold Sugar Zone Mine Expansion

CLIENT: Harte Gold
PROJECT: Sugar Zone Mine Expansion

PROJECT TYPE: Brownfield
LOCATION: Ontario, Canada
SERVICE SCOPE: Design Engineering


Harte Gold’s Sugar Zone process plant was originally designed by Halyard for a throughput of 600 tpd to produce a gravity circuit dore bar and a flotation concentrate. The plant operations team had achieved 700 tpd throughput on numerous occasions. Harte Gold commissioned a feasibility study to consider options for the increase in throughput of the process plant to 1,200 tpd.

The challenge was to investigate options and the economics of gold recovery to increase the existing process throughput, whilst considering additional processes with on-site leaching to eliminate the need to sell the concentrate all whilst considering downtime of the existing process plant during the expansion construction.


The following options were identified and studied:

  • Expansion of the existing process plant,
  • Expansion of the process plant with the addition of a Merrill Crowe leaching circuit, and
  • Expansion of the process plant with the addition of a carbon-in-leach leaching circuit.

The expansion of the existing process plant without the addition of on-site leaching prevailed as the most economical and suitable solution.


After initial delays in obtaining test work data, especially leaching test work, the study was completed in 4 months with three separate process designs including mass and water balances, equipment sizing and complete OEM bids, all civil, concrete, building expansion, mechanical equipment, tanks, pumps and electrical works costing estimates. A full CAPEX and OPEX and Sections 13 and 17 of the NI43-101 feasibility study technical report were authored and signed off by the relevant Qualified Persons.