Screening
The new-age screens are innovative and efficient. It helps to study their specifications so that their functions can be optimised.
The stage of mining where larger ore or mineral particles are separated from smaller particles or gravel is called screening. It is important to choose the right screen and also understand how one can optimise the function.

Understandably, each component in a plant is important for efficiency and for the whole operation to be smooth and seamless.
‘Trickle stratification’ is an interesting phenomenon in the screening process. This occurs when a screen supporting a stationary bed of material of extended size range is shaken, causing the particles to stratify, with finer particles settling at the bottom and coarser particles at the top. Another feature that helps a screening machine become more efficient is the cumulative weight of material passing the screen which is the most used measure of screen efficiency.
It is the cumulative weight of material that has passed the screen in any time interval, compared to the total weight of undersize in the feed, expressed in percentage.
It is also sometimes expressed in the opposite when the oversize is recovered. In that case, the efficiency is the weight percent of material in the screened oversize fraction compared to the total weight of oversize in the feed.
The new-age screening machines with a good rate of stratification of a specific granular material to be separated – also called screenability – are set into four categories, with each category subdivided keeping in mind varied individual differences.
Gyratory Screen:
The principle of this screen is gyration or circular motion of the machine. The gyratory screen operates in a gentler manner than other screens and can handle delicate materials, producing finer products. The method works for both wet and dry screening.
Gyratory equipment is divided into top and bottom units. The top unit consists of screening frames supported with strong springs attached to the circular base, allowing free vibration of the unit. For heavy-duty operation, there are secondary support springs attached. These springs prevent the vibration of the top unit reaching the floor. The bottom unit has top and bottom eccentric weights attached to a heavy-duty motor.
Gyratory screening machines have applications across industries, including chemical, fertiliser, metallurgical, ceramic, refractory materials, grain, food, abrasives and iron ore and limestone mining in the sizing process of material-accurate screening.
Andritz Sprout Roto-Shaker Screeners:
Available in eight model sizes with one to four screening surfaces, this screener can be floor mounted, kept on a stand or suspended by cables. It requires little headroom, making the installation process easy in restricted spaces. Sturdy in design, the machine is designed and built for continuous, trouble-free operation. The computer-balanced dynamic drive provides efficient and low-maintenance operation while minimising structural vibrations.
The General Roto-Shaker screener has wooden frames for reasonable operation, easy handling and quick changes with sectionalised screen frames and a diverter valve discharge option.
On the other hand, the Industrial Roto-Shaker has heavy-duty segmented screen frames, carbon steel or stainless steel construction, better screen life with spring tensioned, hook-up strip screen attachment, and easy adjustment and great efficiency.
Its other features include rugged fiberglass springs that increase screen utilisation and efficiency, adjustable foot-mounted motor and specially formulated rubber ball cleaners that have high bounce and are chemical resistant, easy to maintain with segmented screen decks and top cover, fast
and easy screen changes with our quick-release clamps, ready for cable suspension for space concerns and/or vibration reduction, and rugged channel construction for reducing vibrational stress.
Vibrating screens:
This screen is a continuous bed that shakes at a determined rpm. It is classified as Inclined or Horizontal based on whether there is a direction of motion created by the vibration.

A kind of vibrating screen, inclined vibrating screens are usually inclined to at least 15 degrees and activated by a single oscillator (with eccentric counterweights) that produces desired motion.
The oscillation amplitude is a function of the momentum of the counterweights and the frequency is equal to the shaft rotation speed. The vibration has an elliptical-circular shape, with horizontal axis and diameter proportional to the momentum generated by the eccentric counterweights. Simple and economical, this screening machine is the most common solution across sectors and fit for any screening application, even high-capacity operations.
These screeners can be open or closed (to isolate the product from the environment) and suspended from or supported by the steel framework.
Powerscreen, the world leading manufacturer of mobile crushing and screening equipment has achieved its 50+ year legacy through industry leadership, customer input, continuous innovation and relationships built on trust. The brand has four types of screens – inclined screens, scalping screens, horizontal screens and trommel screens.
As per details, The Powerscreen Chieftain range of mobile incline screens are designed for the processing of aggregates and sand. Within the range there is a model to suit every application, from the legendary Chieftain 1400 through to the BEHEMOTH Chieftain 2200 double screen model which is available in double deck and triple deck varieties. All Powerscreen Chieftain machines are designed to be easily transported, set-up, operated and maintained, while giving excellent tonnages of on-spec material. The Powerscreen® Titan & Warrior Ranges are made up of high capacity, heavy duty, versatile machines capable of screening and separating a wide variety of material in the most difficult and demanding of applications. Common scalping screen applications include recycling, aggregates, compost, topsoil, coal, construction and demolition waste, and iron ore. Their large screening area allows for high volumes of processing. Warriors can be fitted with a huge variety of different screening media, making them some of the most versatile screeners in the industry. The screen media variety, along with fast setup, makes them user-friendly and an excellent option for both ownership and rental.

Powerscreen® Horizon Range Screens are ideal for handling high volumes of sticky materials and for the exact, fine sizing demanded in many construction contracts. The Powerscreen® Horizon range is ideally suited to applications such as natural and crushed aggregate, coal, iron ore, recycled concrete, and asphalt. Powerscreen’s industry leading trommel screens are extremely efficient in separating soil, compost, waste, aggregates, C&D, wood chips, and other materials. The rotating drum allows for tumbling for optimal separation of difficult material along with aeration. Easy drum changes, radial stacking conveyors, rugged components, and support from Powerscreen’s experienced service network make these trommels a versatile and reliable solution.
Kleemann has MOBISCREEN mobile screening plants which are used for screening almost all natural stone types and in recycling. The classifying screens and scalpers are available in a double- or triple-deck version, with hydraulic or diesel-electric drives. The areas of application of the MOBISCREEN plants are multifaceted. A large number of suitable screen surfaces are available for achieving the different final grain sizes and for different feed material. The MOBISCREEN scalping screens are used, for example, before the crushing process for material sorting. Coarse screen surfaces such as slotted grates, finger screens and punched plates are used. Different plant versions are available with double-deck screening units. The classifying screens of the Quarry Line are designed to deal with tough conditions encountered in day-to-day work in a quarry. With their diesel electric drives, they are even more efficient and particularly suitable for linkage with crushers of the KLEEMANN Quarry line. Thanks to their large screening surfaces, high throughput is also guaranteed with small final grain sizes.
MB Screening buckets are ideal for the screening and selection of materials, both before and after the crushing phase. It reduces crushing time by up to 60%, consequently allowing the salvage of materials suited to the type of job being carried out and to manage them in the best way possible. The unique and innovative conical shape of the drum is specially designed to significantly increase the contact area, hourly production performance and to screen all the collected material, residue-free.
MB screening buckets are equipped with baskets formed by interchangeable modular panels. Available in all mesh sizes, depending on the specific needs of the job, the easy assembly and disassembly of the panels makes for quick change to obtain different output material.
The MB Screening Buckets are suitable for all makes and models of excavators, skid loaders, loaders and backhoe loaders.