Flexible and precise for the right material size

Compliance with the specified material size is a decisive factor for efficient work processes in opencast mining. With the Vario Impact Sizer (VIS), Wirtgen offers a system that scores highly in terms of flexibility, precision, and adaptability. It allows machine operators to reliably control the top particle size and particle size distribution even under changing operating conditions. The system has been extensively tested in practice, particularly in coal and bauxite mining, and has proven its worth.

With specific settings to the specified top particle size

The core of the VIS is a split baffle plate mounted directly to the cutting drum housing. This plate is equipped with two primary adjustment mechanisms that enable precise control of the material that passes the system. The variable gap between the plate and the cutting drum is the first adjustment mechanism: this distance can be adjusted in five stages to control the amount of additional crushing and thus change the particle size. A smaller gap results in extra crushing and thus finer material, while a larger gap results in coarser material. The adjustment is made by simply enlarging or reducing the gap and securing the plate with pins what takes approximately 10 minutes. The second adjustment mechanism relates to the holes in the scraper. Depending on the specific requirements of the operation, they can be opened or closed in four different settings using covers. These two mechanisms complement the basic adjustment possibilities of the surface miner like the advance speed of the machine, the speed of the cutting drum, and the cutting depth. In combination with the VIS, this results in an extremely high level of control over the top particle size.

Vario Impact Sizer: durable and stable

Machines in cut-to-ground or windrow applications often produce material that exceeds the specified top particle size. This is where the VIS comes in. The system is designed to fulfill precisely this requirement by influencing and limiting the top particle size. Finer material passes through the sizer and leaves the crushing process while coarser material is crushed until it can pass the sizer too. The VIS has proven itself in both coal and bauxite applications and effectively controls the size of the material produced to ensure that it meets the required specifications. One of the advantages of the VIS is its seamless integration into the machine. The VIS is mounted directly on the cutting drum housing and fits seamlessly into the material processing process. Furthermore, the system is highly adaptable. Thanks to variable settings, different types of rock can be reliably crushed. The VIS is particularly suitable for brittle and porous rocks such as coal, bauxite, or chalk. The robust construction of the VIS ensures that it can withstand the harsh conditions in mining and meets the requirements for durability and stability even at high throughput rates.

Use in opencast mining: Fine control via machine and VIS settings

The VIS is available for the 220 SM(i) 3.8. Particle size control is achieved through the interaction of standard machine settings and the VIS settings. The standard machine settings include the machine’s advance speed from 0 to 84 m/min. The cutting drum speed is also adjustable with six standard settings on board. The cutting depth is adjustable from of 0 to 350 mm. The settings of the VIS consist of the five baffle plate gap settings from 22 mm to fully open and the four cover plate opening settings which can be adjusted from fully closed to fully open. This wide range of combinations offers almost unlimited possibilities to influence the top particle size and the particle size distribution.

Practical examples from coal and bauxite mining applications

The performance of the VIS has been tested in various mining regions in the past. In coal mining in India, the system demonstrated improvements in controlling coal particle size. Specific settings were used to achieve a target size of less than 100 mm. In bauxite mining, the VIS delivered impressive results in the Boffa and Boké regions of Guinea. During mining in Boffa, the sizer was opened fully to enable a cutting depth of 300 mm and a high forward speed, allowing maximum performance to achieve high productivity. In Boké, the settings were adjusted to a material size of less than 100 mm, demonstrating the system’s adaptability to different types of bauxite and different crushing behaviors. Clearly noticeable in practice: the settings have to be adapted to the requirements carefully since with additional crushing, the production rate decreases.

Vario Impact Sizer supports operators in multiple ways

The VIS provides machine operators with a tool that gives them exceptionally precise control over the maximum particle size. The system settings have a direct impact on key performance parameters: particle size distribution, production output, fuel consumption, tool wear, and stress on parts and components. By specifically adjusting the configuration, the operator can always achieve an optimal balance between material requirements, process stability, and overall cost-effectiveness. The VIS thus confirms its role as an effective tool for efficient material size control in modern opencast mining.