In mining, screening is a process used to separate materials based on size, typically involving a series of screens with different mesh sizes to sort crushed or raw materials into various grades or sizes. In mineral processing, several types of screens are used to separate particles based on size, ensuring efficient classification and preparation for further processing.
Inclined screens
The inclined screen remains the most commonly used type thanks to its simplicity and cost-effectiveness. It consists of a frame set at an angle of about 15° to 25° from the horizontal, with screening media attached. A rotating unbalanced mechanism generates a circular motion in the screen body, which, together with gravity, moves the material toward the discharge end. These screens can be built with multiple decks, enabling separation into several size fractions. Their versatility makes them suitable for a wide range of applications. By changing the screen media or adjusting parameters such as the inclination angle, stroke length, and rotation speed, operators can tailor performance to specific needs. This adaptability ensures that inclined screens can be applied to almost any screening task [1].
Horizontal screen
Compared to inclined screens, horizontal screens offer higher accuracy, greater capacity, and require less headroom. Their decks operate at shallow angles (below 10°, sometimes even negative), with material moved forward by linear or elliptical motion rather than gravity. This keeps feed on the screen longer, improving efficiency and making them ideal for secondary screening and final sizing. They are also advantageous where low installation height is needed. However, their more complex drive systems increase cost and maintenance requirements compared to inclined screens [1].
Vibrating screens
Vibrating screens use mechanical vibrations to separate particles and are available in different configurations, including inclined, horizontal, and multi-deck designs. They perform effectively in both wet and dry conditions, making them highly versatile in mineral processing. Common types include circular vibrating screens, self-centred vibrating screens, linear vibrating screens, and high frequency vibrating fine screens. Depending on the application, they are widely used for scalping, sizing, classification, desliming, and dewatering.
Trommel screens
A trommel screen is a rotating circular mesh drum that can sort materials based on their size. The mesh allows small materials like soil or sand to fall through and be collected by a conveyer under the drum. The larger materials flow to the end of the trommel, where they are gathered into another pile [2]. Trommel screens, also known as rotary or drum screens, are cylindrical machines used to separate materials based on size. They consist of a rotating drum with perforations, and as material is fed into the drum, smaller particles pass through the openings while larger particles are discharged at the end. This process is widely used in various industries for screening and sorting materials like soil, compost, and waste.
Reference
[1] “Different types of screens.” Accessed: Aug. 19, 2025. [Online]. Available: https://www.rockprocessing.sandvik/en/the-knowledge-hub/screening-solutions/all-about-screens/different-types-of-screens/
[2] “What is a Trommel?,” Machinery Partner. Accessed: Aug. 19, 2025. [Online]. Available: https://www.machinerypartner.com/blog/what-is-a-trommel
