Analysis of the Application of Feeder Breaker in Open-pit Mining and the Reasons Therefor
The proportion of open-pit coal production in major coal-producing countries is over 90% in India, Indonesia, Germany, and Canada; between 70% and 90% in Australia and Russia; and between 50% and 70% in the United States, South Africa, and Kazakhstan. Most coal is mined through open-pit methods, and the most commonly used primary crushing equipment in coal mining is the feeder breaker.
The feeder breaker is a device that combines feeding and crushing functions. It mainly comes in four forms: chain conveyor with hammer crusher, chain conveyor with jaw crusher, heavy apron feeder with hammer crusher, and heavy apron feeder with jaw crusher. It can be flexibly installed and arranged according to the different production needs of the customer’s site.
The reasons why the feeder breaker is widely used as the primary crushing form in open-pit coal mines are as follows:
In open-pit mining operations, excavators or dump trucks directly transport the mined large blocks of coal to the crushing station. Without a feeder breaker, directly feeding large blocks of coal into the subsequent crushing machine would lead to the following problems:
Blockage and machine jamming: The feed inlet of the subsequent crushing machine is usually small (such as 300mm-600mm), and directly feeding large blocks of coal (which may be up to 2 meters long) would easily cause blockage or damage to the main shaft of the crushing machine.
Equipment wear: Large blocks of coal without preliminary crushing are prone to impact during transportation, causing damage to conveyor belts or chain plates.
Production halt: If the main crushing machine gets jammed, it needs to be shut down for disassembly, resulting in a long-term shutdown of the entire production line.
The working principle of the feeder breaker is that it uses rotating crushing rollers to directly crush large blocks of coal into medium-sized pieces (typically 200mm-500mm), and then continuously convey the crushed coal through the chain conveyor below to the main crushing machine or belt conveyor. This “crushing-feeding” integrated design ensures the continuous flow of materials and significantly reduces the load and failure rate of subsequent equipment.
a. Reduce the impact on the crusher: After the feeder breaker crushes the large blocks of coal, the material becomes powder-like or small pieces, with better fluidity. This “soft feeding” method can significantly reduce the “instantaneous impact” on the jaw crusher or cone crusher, extend the lifespan of the main shaft, and reduce the number of shutdowns for maintenance.
b. Prevent damage to transportation equipment: It can also automatically screen out tramp steel mixed in the coal, preventing excavators or conveyors from being jammed by metal during transportation.
c. Distribute the load: By pre-crushing large blocks of coal, the subsequent main crushing machine (such as jaw or cone crusher) can handle finer materials, improving work efficiency and increasing output.
d. Reduce dust and fines: If large blocks of coal are directly fed into the main crushing machine, a large amount of fines are usually produced, increasing environmental pollution. The milder crushing method of the feeder breaker helps control dust generation.
e. Adapt to large-sized coal: The coal particles in open-pit mines are often very large (commonly 800mm-1500mm), and the feeder breaker is specifically designed to handle such large-sized materials, effectively processing “giant” coal blocks.
f. Strong durability: It usually adopts chain plate conveying and heavy-duty roller design, capable of long-term stable operation in the harsh dust and large temperature difference environment of open-pit mines.
Cost savings and reduced investment:
a. On-site construction costs are reduced: Traditional crushing systems require extensive on-site earthwork to build feed hoppers, lay conveyor belts, and install large support structures.
b. The Feeder Breaker, with its horizontal feeding design, does not require deep excavation for feed hoppers or the construction of high-inclined conveyor belts. This compact layout not only reduces the volume of earthwork but also lowers the costs of concrete pouring and support structures.
c. Small footprint: The Feeder Breaker has a compact (low-profile) design and can be directly placed on the mine surface without the need for extensive infrastructure. It can be directly connected to trucks or loaders, eliminating the need for secondary transfer and thus saving space and related infrastructure investment.
d. Integrated advantages: It integrates the functions of feeding, crushing, screening and conveying into one, eliminating the need for multiple sets of individual equipment. This “one machine, multiple uses” feature can significantly reduce equipment procurement and transportation costs.
Reduce operating costs:
By pre-crushing large chunks of ore, the impact force on subsequent crushers is significantly reduced. This not only extends the service life of the subsequent crushers but also lowers the frequency of machine stoppages and maintenance due to blockages and material jams.
b. Reduce conveyor belt wear: As the materials are crushed more uniformly, the sharp and large pieces that cause wear to the conveyor belt are reduced. The more uniform flow of particle size can also prevent the conveyor belt from slipping or vibrating, thereby reducing the maintenance frequency and the cost of replacing the conveyor belt.
c. It mainly relies on the tension between the crushing teeth rather than simple compression. This crushing method is more energy-efficient than the traditional crushing method, with lower energy consumption per unit of output.
d. Higher crushing efficiency means that trucks or excavators make fewer trips to transport ore to the crushing station. The reduction in transportation distance and frequency directly translates to a significant decrease in diesel or fuel consumption.
Improving production efficiency:
a. The Feeder Breaker is typically equipped with a buffer hopper, which can effectively store and balance the ore flow discharged by upstream loading equipment such as hydraulic excavators or front-end loaders. This design significantly reduces the reliance on the precise dumping rhythm and speed of the loading equipment, allowing it to continuously and efficiently unload at rated conditions while ensuring safety. This reduces idle time and operational breaks caused by waiting for downstream equipment responses, thereby enhancing the system throughput rate and overall equipment utilization in the primary transportation and crushing process.
b. The output material from the Feeder Breaker has a relatively uniform particle size distribution and a continuous and stable feeding flow rate (i.e., achieving a nearly homogenized bulk material flow), which can effectively suppress the load fluctuations of downstream crushing, screening, and conveying equipment caused by large variations in feed particle size or flow pulsation. This ensures the operational stability and overall production capacity utilization of the entire process.
Therefore, the global open-pit mining industry generally prefers to use the Feeder Breaker as a key primary material processing equipment. The Feeder Breaker integrates feeding, crushing, and screening functions, and can efficiently handle the initial processing requirements of large, irregular, and high-hardness raw ores in open-pit mines, significantly improving the operational efficiency and system stability of subsequent crushing, transportation, and beneficiation processes.
Currently, open-pit mining, with its advantages of large-scale production, high efficiency, relatively good safety, short infrastructure construction period, and low operating costs, dominates the development of global metal minerals (such as iron ore, copper ore, bauxite), coal, and non-metallic minerals, accounting for more than 65% of the total global solid mineral production. Against this backdrop, the reliability, adaptability, and intelligence level of mining equipment directly affect the capacity release, energy consumption control, and life-cycle operational benefits of the entire mine.
As a core connection unit between loading equipment (such as electric shovels, hydraulic excavators) and belt conveyor systems or crushing stations, the Feeder Breaker not only needs to withstand high-intensity impact loads and harsh dust environments but also requires advanced functions such as adjustable feeding rates, overload protection, automatic clogging clearance, and remote monitoring. International leading manufacturers have launched a series of Feeder Breaker products suitable for different mineral types, climatic conditions, and transport distance requirements, and are gradually integrating condition monitoring sensors and industrial Internet of Things platforms to support predictive maintenance and digital mine construction. Therefore, scientific selection, standardized operation, and continuous optimization of the Feeder Breaker’s operation management have become an important technical support link for modern large-scale open-pit mines to enhance overall equipment efficiency and sustainable operational capabilities.
