Overview
The Carlin Complex features an integrated network of processing facilities designed to handle diverse gold ore types from multiple open pit and underground sources. The complex utilizes specialized circuits including roasting, pressure oxidation, and heap leaching to maximize recovery based on ore characteristics such as gold grade, oxidation level, and refractory nature.
Key Process Stages
- Gold Quarry Roaster: 4.3 Mtpa capacity facility processing double refractory ores through dry grinding and single-stage roasting (515-538°C) with P80 of 74 µm grind size. Recent upgrades include airslide improvements and new SO2 converter.
- Goldstrike Autoclave: 5.0 Mtpa pressure oxidation plant with parallel CIL trains, converted from thiosulphate to conventional cyanide leaching in 2023. Processes both refractory (acid/alkaline POX) and oxide ores.
- Goldstrike Roaster: 6.6 Mtpa dual-stage fluidized bed roaster (524-593°C) for carbonaceous ores, featuring complete off-gas cleaning and mercury recovery systems.
- Heap Leaching: North and South Area facilities processing low-grade oxide ores (0.25-1 g/t Au) through run-of-mine or crushed ore stacking with CIC recovery.
Critical Data
| Parameter | Gold Quarry Roaster | Goldstrike Autoclave | Goldstrike Roaster |
|---|---|---|---|
| Throughput (Mtpa) | 3.9 (LOM avg) | 3.8 (LOM avg) | 5.1 (LOM avg) |
| Recovery (%) | 83.6 (71-89 range) | 80.8 (74-85 range) | 85.1 (84-90 range) |
| Annual Production (Moz) | 0.6 | 0.2 | 0.8 |
| Power Consumption | 115.74 kWh/t | 248.72 GWh/yr avg | 303.00 GWh/yr avg |
| Key Reagents | Sulphur (2.64 kg/t), Lime (12.21 kg/t) | Sulphuric Acid (5.07 kg/t) | Oxygen (high purity) |
Process Highlights
The Goldstrike Roaster features two parallel dry grinding circuits feeding dual-stage fluidized bed roasters using 99.5% O2 for carbon/sulphide oxidation. The off-gas system includes mercury recovery via chlorine sparging and SO2 neutralization with lime.
The Goldstrike Autoclave operates three parallel vessels (524-561°C) with flexible acid/alkaline POX modes. The 2023 circuit conversion to cyanide CIL from thiosulphate RIL improved recoveries by 5-7% for single refractory ores.
Heap leaching operations utilize sophisticated solution management with CIC recovery, tracking pad inventory through monthly metallurgical balances and kriged grade reconciliation.
Technical report and processing history
The following archived source profiles have been consolidated here to preserve the project’s processing history and study context.
Carlin Complex — 2020 Technical Report
Carlin Complex — 2020 Technical Report
| Company | Nevada Gold Mines LLC |
| Date | 2020 |
| Region | Nevada, USA |
| Commodities | Gold |
Executive Summary
The Carlin Complex represents a major integrated mining and processing operation managed by Nevada Gold Mines LLC, combining assets from Barrick and Newmont. The facility processes ores from multiple open pit and underground sources, utilizing a flexible suite of metallurgical flowsheets to handle various mineralization styles including oxide, sulphide, and refractory ores. The complex is designed to maximize economic returns through synergy, treating single and double refractory materials through roasting, pressure oxidation, and conventional leaching methods.
Processing operations are divided into several distinct circuits, including Mill 5 and Mill 6, the Goldstrike Roaster and Autoclave, and multiple heap leach areas (North, South, and Emigrant). The Goldstrike Autoclave utilizes pressure oxidation followed by thiosulphate leaching (CaTS) and resin-in-leach (RIL) to treat refractory sulphide ores, while the Roaster circuit employs fluidized bed roasting to oxidize carbonaceous and sulphide minerals before cyanide leaching. Heap leaching facilities handle low-grade oxide ores using cyanide solution and carbon-in-column (CIC) recovery.
The operation maintains a high level of flexibility to treat different ore types based on grade, oxidation level, and proximity to facilities. Throughput varies by circuit, with the Autoclave grinding capacity at approximately 16,000 dry tonnes per day and annual tonnages ranging from 3.1M to 5.7M tonnes depending on the specific plant and ore blend. The complex is currently in an operating status with sufficient infrastructure for power, water, and process materials to support the life of mine plans.
Website: https://www.barrick.com/English/operations/nevada-gold-mines/default.aspx
Report Date: 2020
Region: Nevada, USA
Project Status:
Commodity: Gold
Throughput:
Mine Life:
Mine Type:
Ore type:
Carlin Operations — 2019 Technical Report
Carlin Operations — 2019 Technical Report
| Company | Newmont |
| Date | 2019 |
| Region | Nevada, USA |
| Commodities | Gold |
| Mine Type | Open Pit and Underground |
| Status | Operating |
Executive Summary
This section of the NI 43-101 Technical Report details the recovery methods employed at the Carlin metallurgical complex. The facility processes ores from multiple open pit and underground sources using an integrated process production plan designed for maximum economic returns. Ores are classified based on gold grade, oxidation level, and refractory characteristics to determine the appropriate treatment method.
Three primary processing options are utilized: heap leach pads for oxide ore, Mill 5 for flotation and cyanide leaching, and Mill 6 for refractory ore using roasting and leaching. Intermediate products from Mill 5 and Mill 6 are sometimes sent to the Twin Creeks autoclave plant for further oxidation and gold recovery. The report outlines the specific flowsheets, consumables, and operational parameters for each facility, including energy and water requirements.
The metallurgical flowsheets and recovery estimates are considered appropriate based on over 40 years of production data. The project has sufficient infrastructure for power and water extraction permits to support operations through the Life of Mine (LOM).
Website: https://www.newmont.com/about-us/default.aspx
Report Date: 2019
Region: Nevada, USA
Project Status: Operating
Commodity: Gold
Throughput:
Mine Life:
Mine Type: Open Pit and Underground
Ore type:
