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Screenshot 2026-07-31 150538

Harp Screens and Flex Mats: Improving Throughput in Difficult to Screen Materials

Harp Screens and Flex Mats: Improving Throughput in Difficult to Screen Materials

At ScreenProducts, screening performance comes down to one thing: if your screens underperform, your plant underperforms. Harp screens and Flex-Mats are built to keep throughput up on materials that blind or peg conventional weaves – wet, sticky, or fine feed.

What Is a Harp Screen?

Harp weave is one of ScreenProducts’ standard woven wire weaves, alongside plain, intermediate, lock crimp, flat top and slotted. The wires run parallel under tension rather than interlocking, so each wire flexes independently – giving the screen a natural self-cleaning action. Harp weave screens are supplied in high carbon spring steel, stainless steel 304, or stainless steel 316.

Harp Screens vs Flex Mats

Both are harp weaves, but how they’re bound changes everything:

  • Binding – traditional harp screens use wire (usually two or three wires); Flex-Mats use bonded 90 Shore polyurethane strips instead
  • Flat surface – wire binding runs up and over the mesh, lifting it near the aperture edge; PU bands sit flush for a fully flat screening surface
  • Failure mode – one broken binding wire and a traditional harp screen falls apart; a bonded PU band doesn’t fail the same way
  • Open area – traditional harp binding wire pitch tops out around 150mm – 180mm; Flex-Mats can run 300mm – 350mm, for significantly more open area
  • Panel joins – Flex-Mats allow a PU overlap between panels; traditional harp screens need a wire finish instead
  • Compatibility – Flex-Mats work on both static and mobile screening units
  • Cost – Flex-Mats cost more upfront, but a traditional harp screen may need replacing two or three times over the working life of a single Flex-Mat

Engineering the EaziFlow Panel

Flex-Mats are manufactured using high-quality 90 Shore polyurethane. Camber bar and PU band placement is what makes an EaziFlow panel perform:

  • Main PU wear bands sit directly above the camber bars
  • Camber bar bands are cast at 25mm, intermediate bands at 15mm
  • Reinforced PU is added along the hook edge, the first point of wear
  • Two weave types: Square harp (2mm aperture and above), Tri harp (1.1mm aperture and above)

Open Area Drives Throughput

Screening efficiency comes down to open area – more holes means material passes through faster, with less abrasive wear on the screen. Wire that’s too thick for the aperture extends screen life but shrinks open area, so throughput drops instead of rising. The right ratio depends on feed size and material density – ScreenProducts’ full reference table is available on request.

 

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Interstage Screens: Function, Selection, and Applications

In a carbon-in-leach (CIL) or carbon-in-pulp (CIP) gold recovery circuit, interstage screens are critical control points. Their function is to retain activated carbon within each adsorption tank while allowing the process slurry to pass through to the next stage. When interstage screens perform correctly, carbon stays in the circuit, gold adsorption continues as designed, and plant throughput is maintained. When they do not, carbon losses accumulate, gold recovery falls, and the cost of the problem often exceeds the cost of replacing the screens that caused it.

Screen Products designs and manufactures precision wedge wire interstage screens for CIL and CIP plants, elution columns, acid wash columns, and carbon safety screen applications. This post covers how interstage screens fit into the gold recovery process, how wedge wire technology works, what the key screen parameters are, and why screen quality has a direct bearing on plant profitability.

Where Interstage Screens Sit in the Gold Recovery Process

Understanding the role of interstage screens starts with understanding the process they are part of.

Run-of-mine ore is first crushed and ground to liberate gold particles. The ground ore is then leached with cyanide solution to dissolve the gold into solution. From there, the gold-containing slurry enters a series of adsorption tanks.

In a CIL circuit, activated carbon is added directly to the leaching tanks so that adsorption begins simultaneously with leaching. In a CIP circuit, the ore is leached first and carbon adsorption occurs in a separate series of tanks downstream. In both configurations, activated carbon is the medium that captures dissolved gold from the slurry as it moves through the circuit.

The interstage screen sits at the discharge point of each tank. Slurry flows through the screen apertures into the next tank. The activated carbon, which has a coarser particle size than the slurry, is retained within the tank by the screen. This allows the slurry to progress through the circuit while the loaded carbon accumulates for transfer to elution.

Why Carbon Loss Is a Plant Performance Problem

Activated carbon losses are one of the most common and costly problems in CIL and CIP operations. Plants with underperforming interstage screens regularly experience activated carbon losses, reduced gold adsorption capacity, carbon carry-over into downstream areas of the circuit, screen failures that require unplanned shutdowns, and excessive maintenance frequency.

The financial consequence of carbon loss is direct. Carbon that leaves the circuit carries adsorbed gold with it. Even small, consistent losses compound across the life of the circuit into a material reduction in gold recovered. Beyond the gold loss itself, carbon replacement adds to operating costs, and unplanned maintenance to address screen failures increases downtime.

The key financial principle here is straightforward: the cost of lost carbon, including the gold it carries and the operational disruption it causes, frequently exceeds the cost of specifying and maintaining quality interstage screens in the first place. Carbon loss reduction translates directly to improved recovery. Reduced downtime increases throughput. Longer screen life lowers replacement costs. These are measurable outcomes, not theoretical benefits.

How Wedge Wire Technology Works

A wedge wire screen is made up of V-profile wire strands welded to support rods at regular intervals. Because the profile is wedge-shaped (wider at the back, narrower at the face), the aperture widens inward, so particles too large to pass through fall away from the surface rather than lodging in the slot, keeping open area consistent over time. The welded construction provides the rigidity needed to withstand continuous agitation inside a CIL or CIP tank. 

 

Screen Parameters 

Screen Products manufactures interstage screens to client specification, with slot sizes from 0.25mm to 2.50mm to retain activated carbon while allowing free slurry flow. Material options are SS304, SS316, or Duplex stainless steel, with SS316 and Duplex specified where process chemistry demands higher corrosion resistance. Screens are custom manufactured to match the specific tank configuration, available in two configurations: the MPS Interstage Screen and the MPS(P) Interstage Screen.

 

Applications Across the Gold Recovery Circuit

Interstage screens are the primary application, but Screen Products’ wedge wire technology is used at several other points in the gold recovery and carbon management process.

Elution Columns: During elution, gold is stripped from loaded carbon using a hot caustic cyanide solution under pressure. Wedge wire screens within the elution column retain the carbon bed while allowing the eluate to flow through. The chemical and temperature environment inside an elution column places specific demands on the screen material and construction, which is why elution column screens are specified separately from interstage screens.

Acid Wash Columns: Before elution, carbon is typically acid-washed to remove calcium carbonate scale and other foulants that reduce adsorption efficiency. Acid wash column screens retain the carbon during this process. The acidic environment requires appropriate material selection.

Carbon Safety Screens: Carbon safety screens are installed at key discharge or transfer points to catch any carbon that passes through the interstage screens. They act as a secondary retention point, limiting the extent of carbon losses when interstage screen performance degrades.

Beyond gold processing, Screen Products’ wedge wire capability extends to DSM screens (sieve bends) for dewatering and classification across mining, minerals, coal preparation, and other industries where liquid-solid separation is required.

Find the Right Screen for Your Circuit

Interstage screens are not a commodity item in a gold recovery circuit. The slot size, material grade, open area, and construction quality of each screen has a direct bearing on carbon retention, gold recovery, and plant availability. Underperforming screens do not just cause maintenance problems. They cause gold loss, and that loss accumulates with every tonne processed.

Screen Products designs and manufactures precision wedge wire interstage screens for CIL plants, CIP plants, elution columns, acid wash columns, and carbon safety screen applications. Screens are custom manufactured to client specifications, with slot sizes from 0.25mm to 2.50mm and materials including SS304, SS316, and Duplex stainless steel.

 

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Woven Wire Screens: The Complete Guide

Woven Wire Screens

In mining, quarrying, and aggregate processing, the screen deck is where production efficiency is won or lost. When your screens are correctly specified, fines pass through quickly, oversizes are accurately rejected, and your plant runs at full capacity. When they are not, the entire operation pays the price in lost throughput, premature wear, and unplanned downtime.

Woven wire screens are the industry’s most widely used screening media — delivering superior open area, precise aperture geometry, and the toughness to handle continuous high-impact loading. But specification matters. The wrong weave type, wire diameter, or hook configuration can cut screen life and throughput significantly.

With over 50 years of screening expertise, ScreenProducts engineers woven wire screens specifically for your application, your material, and your machine.

Weave Types

The aperture-to-wire ratio determines which weave is used as standard in most cases. ScreenProducts supplies the following weave types:

1. Plain Weave

The most common woven wire configuration. Single over/under interlace creates the highest open area of all weaves. First choice for light to medium-density materials where throughput is the primary objective.

2. Intermediate Weave

A modified plain weave with tighter crimp spacing. Balances open area with improved wire stability. Used where plain weave lacks sufficient rigidity for the application.

3. Lock Crimp Weave

Wires are mechanically locked at each intersection, preventing movement under vibration and impact. The correct choice for coarser apertures — typically above 25mm — and high-impact loading zones.

4. Flat Top — Square and Slotted

The upper wire surface is flattened to create a smooth, level screening plane. Reduces material degradation and improves cut-point accuracy. Specified for sensitive products such as washed concrete aggregate and industrial sand.

5. Slotted — Single / Double / Triple Shute

Elongated rectangular apertures formed by multiple parallel weft wires. Highly effective for flaky, elongated, or blinding-prone materials such as coal and recycled aggregates. Triple shute maximises slot length for the most difficult screening duties.

6. Harp — Square and Tri

Parallel wires run the full screen length, held by polyurethane wear bands rather than cross-wires. Maximum open area with minimal pegging. The preferred choice for fine-to-medium wet screening and the basis for the EaziFlow range.

7. Heavy Duty Welded Screen

Welded wire intersections deliver maximum structural integrity for primary screening, extreme impact loading, and large-lump applications where conventional weave would distort under load.

8. Customised to Suit Application

Bespoke weave configurations engineered to non-standard aperture sizes, combined geometries, or unique dimensional requirements. Contact ScreenProducts with your specification.

Wire Materials

The mineral being screened and any contaminants present will determine which wire material is most suitable for your application. ScreenProducts supplies woven wire screens in the following materials:

  • High Carbon Spring Steel – The standard choice for the majority of screening applications. Delivers high tensile strength and durability under demanding screening conditions.
  • Stainless Steel 304 – Specified where corrosion resistance is required. Suitable for applications involving moisture or mild corrosive environments.
  • Stainless Steel 316 – Offers superior corrosion resistance compared to 304. Specified for more aggressive or chemically demanding screening environments.
  • Any Other Material on Request – ScreenProducts can source and manufacture woven wire screens in alternative materials to suit your specific application. Contact us with your requirements.

 

Hook Types

The specification of your vibrating screen will determine the correct hook type to be used. Using the incorrect hook type will result in poor screen tensioning and fitment.

ScreenProducts supplies woven wire screens in the following hook configurations:

  • Plain 45°
  • 45° Metal Edge
  • Double Fold Metal Edge
  • C-Shape Weld On
  • Plain C-Shape
  • C-Shape Metal Edge

Why ScreenProducts

ScreenProducts is one of the few companies offering a comprehensive range of screening media and related accessories under one roof. Beyond product supply, we provide on-site technical support and practical problem-solving to optimise performance and ensure maximum screening efficiency.

  • Over 50 years of hands-on screening expertise.
  • Full weave range including customised configurations.
  • All wire materials — High Carbon Spring Steel, Stainless Steel 304, Stainless Steel 316, and specialist alloys on request.
  • All hook types to match any vibrating screen OEM specification.
  • On-site surveys and installation support.

Contact ScreenProducts

To discuss your woven wire screen requirements — whether you need a standard replacement screen, an OEM-matched mobile screen specification, or a custom weave configuration — contact the ScreenProducts team directly.

With over 50 years of screening expertise, our team will ensure your screens are correctly specified for your application, your material, and your machine.

Polyurethane Panels The High-Performance Screening Media Tegman

Polyurethane Panels: The High-Performance Screening Media

When it comes to screening media that delivers consistent performance under the most demanding industrial conditions, polyurethane screening panels have become the go-to solution across mining, quarrying, recycling, and processing operations throughout South Africa and beyond.

Polyurethane screening panels are installed on vibrating screens, trommel screens, and a wide range of other screening equipment to separate materials by size. Their combination of abrasion resistance, flexibility, and self-cleaning design makes them a cost-effective and high-performance alternative to traditional rubber or steel screening media.

At Screen Products, we supply a comprehensive range of polyurethane panels, mats, and accessories engineered to meet the specific demands of your operation — from coarse aggregate separation to fine-sand screening applications.

What Are Polyurethane Screening Panels?

Polyurethane (PU) screening panels are manufactured from high-grade polyurethane compounds and are designed to be fitted onto vibrating screens, trommel screens, and similar screening equipment. They function by allowing undersized material to pass through defined apertures while retaining oversized particles on the screen surface.

Unlike steel wire mesh or rubber mats, polyurethane screening panels offer a unique combination of flexibility and hardness that allows them to withstand impact, resist abrasion, and flex under load — significantly extending their operational service life.

Their modular design and lightweight construction also make them considerably easier to install and replace compared to traditional screening media, reducing unplanned downtime and maintenance costs on site.

Industries That Use Polyurethane Screening Panels

Polyurethane screening panels are used across a broad range of industries where accurate, reliable material separation is critical. The table below outlines the key industries and their typical screening applications:

  1. Mining — Screening of coal, iron ore, gold, copper, and other minerals
  2. Quarrying & Aggregates — Separation of crushed stone, gravel, and sand
  3. Cement Plants — Screening of raw materials and clinker
  4. Steel & Foundry — Screening of coke, sinter, and raw feed materials
  5. Recycling — Sorting of plastics, glass, scrap metals, and construction waste
  6. Fertiliser & Chemical — Sifting of chemical powders and granules
  7. Food Processing — Coated, food-grade PU panels used in specific dry food screening applications

The versatility of polyurethane screening panels means they can be adapted for use across virtually any bulk material handling or processing environment — making them one of the most widely used forms of screening media in heavy industry today.

Types of Polyurethane Screening Panels

Screen Products supplies a full range of polyurethane panel types to suit different screening setups, material types, and equipment configurations:

1. Modular Polyurethane Panels

Modular panels are the most commonly used type of polyurethane screening media. They are available in standard sizes of 305 x 305 mm, 305 x 610 mm, and 610 x 610 mm and are designed for quick, easy installation using a pin-and-sleeve fixing system. Their modular design allows individual panels to be replaced without disturbing the rest of the screen deck, minimising downtime during maintenance changeouts.

2. Tensioned Polyurethane Panels

Tensioned panels are hooked for side or end tensioning and are suited to applications where a taut, flat screening surface is required. They are typically used on inclined vibrating screens and are well suited to wet screening applications in mining and aggregate processing environments.

3. Flip Flow Screens

Flip flow polyurethane screen panels are specifically engineered for high-moisture and sticky material applications. Their unique flex-and-snap action prevents material blinding and pegging, making them ideal for screening difficult-to-process materials such as damp coal, clay-contaminated aggregates, or sticky minerals that would blind conventional screen panels.

4. Fine Mesh Polyurethane Panels

Fine mesh polyurethane panels are designed for precision screening applications where accurate particle size separation at smaller aperture sizes is required. They are manufactured from polyurethane to maintain aperture integrity and resist blinding, even at fine mesh sizes.

5. Derrick Screen Panels

Derrick screen panels are engineered specifically for fine-sand screening applications. They fit most Derrick screen machines and are manufactured to allow screening with very small apertures, making them the preferred choice for fine wet classification in sand washing and mineral processing plants.

Key Benefits of Polyurethane Screening Panels

The performance advantages of polyurethane screening panels over traditional rubber and steel screening media are well established across heavy industry. The table below summarises the key features and their operational benefits:

  1. Abrasion Resistance — Longer service life than rubber or steel screens
  2. Reduced Downtime — Less frequent replacement means lower ongoing maintenance costs
  3. Noise Reduction — Quieter operation compared to steel panels, improving on-site working conditions
  4. Corrosion Resistance — Withstands exposure to chemicals, water, and environmental factors
  5. Flexibility & Impact Resistance — Withstands heavy and sharp materials without cracking or fracturing
  6. Self-Cleaning Design — Tapered or modular apertures help prevent blinding and pegging
  7. Modular Systems Available — Easy and quick installation or individual panel replacement
  8. Lightweight Construction — Easier to handle safely during installation and maintenance changeouts

These performance characteristics make polyurethane screening panels a sound long-term investment for any operation that requires reliable, continuous screening performance with minimal maintenance intervention.

Panel Sizes and Aperture Types

Screen Products stocks polyurethane screening panels in the following standard sizes:

  • 305 x 305 mm
  • 305 x 610 mm
  • 610 x 610 mm

Note: Custom sizes are available on request to accommodate non-standard screen deck configurations.

Available Aperture Types

Panels are supplied in a range of aperture configurations to suit different screening applications:

  • Square apertures — general-purpose separation across most material types
  • Non-binding apertures — designed to reduce pegging and blinding in sticky or elongated material
  • Small slotted apertures — suited to applications requiring shape-based separation
  • Large slotted apertures — used for higher-throughput screening of coarser materials

Poly Wedge, Poly Wire & Poly Perf Panels

In addition to standard modular and tensioned polyurethane panels, Screen Products also supplies a range of specialised panel types designed for specific screening requirements:

  • Poly Wedge Panels — available in 610 x 610 mm and 305 x 305 mm (L-shape) configurations, these panels use wedge-wire-style apertures cast in polyurethane for high open-area and accurate sizing.
  • Poly Wire Panels — available in 305 x 610 mm, these panels incorporate a wire-reinforced polyurethane construction for enhanced strength and durability in demanding applications.
  • Poly Perf Panels — available in 305 x 610 mm and 610 x 610 mm, these panels feature perforated aperture patterns and are well suited to fine screening and classification applications.

All Poly Wedge, Poly Wire, and Poly Perf panels are available in the same panel sizes as our standard PU panels, across many aperture types, and in a variety of fixing methods to suit your existing screen deck infrastructure.

 

 

High-Frequency PU Mats (HFM)

High-Frequency Polyurethane Mats (HFM) are a specialised form of polyurethane screening media designed for fine screening applications that require very small apertures. They are manufactured from high-grade polyurethane and are engineered to fit most Derrick screen machines.

HFM panels are available in both tensioned and modular formats, making them versatile across different screening setups and equipment configurations. Common panel sizes include **1 040 x 700 mm** and **305 x 610 mm**.

Their lightweight construction enhances handling safety on site and significantly reduces manual handling time during maintenance or panel changeouts — an important consideration in high-frequency screening environments where regular maintenance is required.

Wire-coated mat variants, including wire coated with polyurethane (PU), are also available where additional structural reinforcement is required without compromising the screening performance of the panel.

Polyurethane Screening Panel Accessories

Screen Products supplies a complete range of accessories to support the installation, maintenance, and optimisation of polyurethane screening panels on your equipment:

  • Pins & Sleeves — used to secure modular panels to the screen deck frame
  • Side Liners — protect the sides of the screen deck from abrasive material wear
  • Brackets & Wedges — provide secure panel fixing and alignment on the screen frame
  • Clip Rails — used for the rapid attachment and removal of tensioned panels

All accessories are available in sizes compatible with our full range of polyurethane panels, ensuring a complete, integrated screening solution from a single supplier.

Why Choose Screen Products for Your Polyurethane Screening Media?

Screen Products is a dedicated screening media specialist supplying high-quality polyurethane panels, mats, and accessories to mining, quarrying, and processing operations across South Africa. With branches in Durban (Ballito), Gauteng, Nelspruit, and Cape Town, we are well positioned to support your operation with reliable product supply and expert technical advice.

Our team of experienced technical specialists works closely with customers to identify the most appropriate panel type, aperture configuration, and fixing method for each specific application — ensuring that your screening equipment performs at its best, for longer.

Whether you are looking to upgrade your existing screening media, reduce maintenance downtime, or solve a persistent blinding or pegging problem on your screen deck, our polyurethane panel range has a solution to meet your needs.