Overview
The DDGM Processing Facility is a sophisticated mineral processing plant handling polymetallic ore from the Arista and Switchback underground mines. The facility features both sequential flotation (sulfide) and agitated cyanide leach (oxide) circuits, producing three separate saleable concentrates (gold-copper, silver-lead, and zinc) along with doré bars. Commissioned in 2010, the plant has undergone several upgrades including the 2014 installation of a Gekko Systems InLine Leach Reactor™ and a 2022 sulfur flotation circuit addition.
Key Process Stages
- Crushing and Milling: Three-stage crushing (jaw + 2 cone crushers) reduces ore to -9.5mm, followed by parallel ball mill circuits (3.2m diameter mills with 798kW and 597kW motors)
- Differential Flotation: Sequential production of Cu/Au/Ag, Pb/Ag/Au, and Zn concentrates through multi-stage cleaning circuits
- Gravity Concentration: Knelson concentrator processes cyclone underflow (decommissioned in 2024)
- Sulfur Flotation: Added in 2022 to recover residual gold-bearing sulfur from zinc tailings
- Agitated Leaching: 5-tank cyanide circuit (170m³/tank) with CCD washing and Merrill-Crowe precipitation (decommissioned in 2023)
- Tailings Management: Dual filter presses (50-60 TPH combined) produce dry stack tailings at 14% moisture for open pit deposition
Critical Data
| Parameter | Value |
|---|---|
| 2024 Throughput | 356,633 tonnes (977 tpd average) |
| Metal Production (2024) | 9,906 oz Au, 919,836 oz Ag, 642t Cu, 2,682t Pb, 7,744t Zn |
| Metallurgical Recoveries | 77.1% Au, 88.3% Ag, 69% Cu, 68.3% Pb, 79.8% Zn |
| Head Grades (2024) | 1.12 g/t Au, 90.88 g/t Ag, 0.26% Cu, 1.1% Pb, 2.72% Zn |
| Crushing Capacity | 110 tonnes/hour |
| Ball Mill Specifications | Mill 1: 3.2m x 4.29m (798kW), Mill 2: 3.2m x 3.68m (597kW) |
| Leach Tank Capacity | 5 x 170m³ agitated tanks |
| Tailings Moisture | 14% after filtration |
Laboratory Capabilities
The on-site laboratory processes 100 samples/day with 400+ daily assays using:
- Fire assay (5-20g samples at 1050°C)
- XRF spectroscopy (3-5 min/sample)
- Atomic absorption spectroscopy (2 Perkin Elmer units)
- Full metallurgical testing suite including flotation, cyanidation, and filtration tests
