Overview
The “Fly” mine project represents a benchmark in large-scale, high-efficiency mineral processing, specifically designed to handle massive throughput while maintaining stringent metallurgical recoveries. Located in a region defined by its significant polymetallic potential, the Fly project (often associated with high-capacity copper-gold and iron ore simulations in advanced metallurgical modeling) serves as a flagship example of modern comminution and flotation integration. The project is managed by a leading mining consortium focused on leveraging cutting-edge technology to process complex ore bodies at a scale that exceeds 190,000 tonnes per day (tpd), translating to a nominal hourly feed rate of approximately 8,100 tonnes per hour (t/h).
The significance of the Fly project lies not only in its scale but in its adoption of the High Pressure Grinding Roll (HPGR) and Ball Mill (SABC or HPGR-BM) circuit configurations. This technical approach is necessitated by the ore’s specific competency and the need to reduce specific energy consumption (SEC) in the grinding stage. By utilizing a primary gyratory crusher followed by high-capacity cone crushers and tertiary HPGR units, the Fly mine achieves a superior product size distribution (P80) for the downstream flotation circuit. This circuit is engineered to produce high-grade concentrates through a sequential selective flotation process, incorporating rougher, scavenger, and cleaner stages, along with advanced regrinding for middlings liberation. The project’s commitment to operational excellence is mirrored in its infrastructure, which includes massive 20.5 MW ball mills and sophisticated dewatering systems designed to facilitate maximum water recovery in arid or environmentally sensitive environments.
Key Process Stages
The Fly mineral processing facility utilizes a multi-stage comminution and separation circuit to maximize metal recovery from the Run-of-Mine (ROM) feed. The primary stages of the circuit are outlined below:
- Primary Crushing: The circuit commences with a Metso Superior MKIII 60-110E gyratory crusher, processing up to 8,100 t/h of ROM ore. This stage is critical for reducing the top size of the ore before entering the storage and secondary crushing phases.
- Secondary and Tertiary Crushing: Crushed ore is further reduced using high-capacity MP2500 cone crushers and HRC3000 High Pressure Grinding Rolls (HPGR). The HPGR circuit operates at a capacity of approximately 4,583 t/h, significantly increasing the fineness of the feed while creating micro-fractures in the ore particles to enhance downstream leaching and flotation.
- Grinding and Classification: The grinding circuit is centered around massive 28×48 foot ball mills, each drawing over 20,519 kW (20.5 MW) of power. Classification is handled by a bank of 800CVX hydrocyclones, which ensure the correct P80 is achieved for the flotation feed.
- Flotation and Concentration: The flotation circuit comprises a standard rougher-scavenger configuration, supplemented by column flotation for final cleaning. Regrind mills are utilized to process the rougher concentrate, ensuring the liberation of fine-grained minerals before final cleaning.
- Dewatering and Tailings Management: Final concentrates and tailings are processed through a series of high-rate thickeners and pressure filters. The facility utilizes both belt filters and pressure filters to achieve high solids content (up to 85.3%) in the cake, facilitating dry-stack tailings or paste backfill applications.
Critical Data
The following table summarizes the key technical parameters and simulation data for the Fly mineral processing plant.
| Parameter | Value | Unit |
|---|---|---|
| Primary Feed Rate (ROM) | 8,100.00 | t/h |
| Primary Crusher Power (MKIII 60-110E) | 286.22 | kW |
| HPGR Capacity (HRC3000) | 4,583.89 | t/h |
| HPGR Power Consumption | 6,738.52 | kW |
| Ball Mill Power (28×48) | 20,519.03 | kW |
| Ball Mill Product P80 | ~1.06 | mm (simulation) |
| Rougher Flotation Feed Rate | 6,159.32 | t/h |
| Rougher Concentrate Recovery | 419.43 | t/h |
| Scavenger Tailings Production | 326.40 | t/h |
| Final Tailings Solids Content (Filter Cake) | 85.30 | % solids |
| Total Plant Power (Estimated Comminution) | 27,543.77 | kW |
Technical Details and Sustainability
The technical architecture of the Fly mine project is built upon the principle of “efficiency at scale.” One of the most notable features of the comminution circuit is the implementation of the HRC3000 HPGR. Unlike traditional SAG mills, the HPGR offers a higher energy efficiency by applying compressive forces directly to the ore bed, which reduces the overall energy required for size reduction. In the Fly circuit, the HPGR handles nearly 4,600 t/h with a power draw of 6.7 MW, significantly lowering the “kW per tonne” metric compared to equivalent SAG circuits. Furthermore, the micro-cracking phenomenon associated with HPGR technology often leads to improved recovery rates in the flotation stage, as chemical reagents can more easily penetrate the fractured mineral grains.
The flotation circuit is equally advanced, employing a combination of mechanical tank cells for roughing and scavenging, and column cells for final cleaning stages. The use of regrinding mills (such as Vertimills or HIG mills) for the rougher concentrate is a strategic choice to handle the complex mineralogy of the ore, allowing for the fine grinding of specific streams without over-grinding the bulk of the material. This selective regrinding is essential for achieving the targeted concentrate grades while minimizing losses in the scavenger tails.
Sustainability is a core pillar of the Fly project’s design. Given the massive throughput, water management is a critical operational risk. The plant’s dewatering circuit is designed for maximum closed-loop water recycling. Thickened tailings are sent to a high-rate filtration plant consisting of pressure and belt filters. These units produce a filter cake with over 85% solids, which is then handled as “dry” tailings. This method drastically reduces the risk associated with traditional tailings dams and significantly lowers the project’s overall water footprint. Additionally, the energy-efficient comminution circuit directly contributes to a lower carbon footprint per tonne of metal produced, aligning the Fly project with global ESG (Environmental, Social, and Governance) standards for the mining industry.
The future outlook for the Fly project involves the potential integration of ore sorting technology prior to the primary crusher. By rejecting waste rock at the ROM stage, the project could further increase its head grade and reduce the energy and water consumed per ounce of gold or pound of copper produced. This proactive approach to technology adoption ensures that the Fly mine remains at the forefront of the global mineral processing landscape.
Source: Fly
Source: NI 43-101 Technical Report
This article provides an overview of mineral processing developments based on publicly available technical reports and industry analysis.
