Application-Specific Modifications Improve Mining Strainer Efficiency

June 17, 2026 - Mining engineers and plant managers oversee a wide range of environmental compliance responsibilities, including the management of slurries, ore processing streams, and the water used for separation, cooling, dust suppression, and washdowns. Advanced filtration is also critical for treating water strained from pits, sumps, wash bays, stormwater collection points, milling, beneficiation, and chemical leaching processes. As a result, dependable automatic scraper strainers play an important role in maintaining uptime while supporting broader water management and compliance goals.

Today, automatic scraper strainers are among the closest solutions to a true “set-and-forget” system, effectively removing both large and fine suspended solids from mine water, process water, cooling tower water, liquids, and slurries.

The basic design represents one of the most efficient and cost-effective industrial self-cleaning strainers available. The motorized unit is engineered for minimal maintenance and operator involvement and can remove solids as small as 75 microns. These strainers allow for continuous, uninterrupted flow, including during blowdown cycles.

Acme FRP strainer control panel view

Cleaning is performed by a spring-loaded blade and brush system controlled by a fully automatic control unit. The two blades and two brushes rotate at 8 RPM, for a total of 32 passes per minute. The scraper brushes penetrate the wedge-wire slots to dislodge stubborn particulates and adhered solids.

This design enables the scraper strainers to resist clogging and fouling even in mining applications with large debris and high solids concentrations. It also ensures a complete cleaning and is very effective against organic matter biofouling.

However, incorporating minor customizations or application-specific modifications can further optimize the automatic scraper strainer’s performance and suitability for a given mining application, according to Robert Presser, President of Acme Engineering Products, Inc., a North American manufacturer of industrial self-cleaning strainers. Acme Engineering Products, Inc. is an ISO 9001:2015–certified manufacturer of environmental control systems with integrated mechanical, electrical, and electronic capabilities.

 

Acme Strainers rigid design for viscous fluids, heavy solids

Presser recommends the following design refinements that can improve overall effectiveness and operational results of scraper strainers for mining and mineral processing applications.

Choose the Screen Best Suited to the Application

 

Scraper strainers are available in various screen constructions, each engineered to address different process requirements and operating conditions.

Reverse formed wedge wire screens are the most common screen type used due to their strength, durability and resistance to deformation resulting from high differential pressures. The smooth continuous slot profile minimizes particle wedging and facilitates the use of automated brush cleaning systems. 

For processes that require finer filtration, multilayer sintered metal mesh screens are a good option. These screens consist of multiple layers of woven wire mesh bonded together to form a rigid, porous structure. 

Fine particulates should often be removed before water is routed to downstream treatment, reuse, discharge polishing, spray nozzles, heat exchangers, or instrumentation. Otherwise, suspended solids can interfere with later treatment stages, clog or erode sensitive components, and reduce overall system reliability.

Perforated screens with circular holes are optimal in applications handling stringy or fibrous materials like those commonly found in some mine dewatering, washdown, and stormwater collection points. The round-hole geometry reduces the tendency of fibers to lodge in the openings, promoting easier self-cleaning and more reliable operation. As a result, these screens help maintain stable flow conditions and reduce the risk of blinding in fiber-laden process streams.

Affordable Solutions for More Effective Solids Removal

Scraper strainers allow the solids to accumulate at the bottom of the vessel, where the blowdown valve will open periodically to clear them out. Blowdown occurs only at the end of the intermittent scraping cycle when a valve is opened for a few seconds to remove solids from the collector area. Liquid loss is minimal, accounting for less than one percent of the total system flow. 

If additional pressure is required to clean the screen, however, an inexpensive trash pump can be added to the blowdown line to assist in removing the solids, debris, and sediment that collect in the strainer sump.

Alternatively, the sump can be replaced by a cylinder bracketed by two gate valves that open and close as needed to remove the solids waste.

“When you are ready to empty the cylinder, you close the top gate valve momentarily and open the bottom one by depressing a button to dump the accumulated solids into a receptacle like a dump truck or a conveyor bucket so there is no manual handling required,” says Presser.

Add a Macerator to Break Up Large Solids

For applications with high solids loading that are prone to clogging, a macerator can be installed upstream of the automated scraper strainer. This solution accommodates heavy solids loading while ensuring uninterrupted flow and dependable, clog-free performance.

“The design effectively delivers a one-two punch, with the macerator breaking down large solids into smaller fragments and the automated scraper strainer efficiently filtering out the debris along with the tiny particles,” explains Presser. 

The combination of these two established technologies is already being applied to some of the toughest, dirtiest straining applications including wastewater debris, power plant boiler water slag, asphalt transloading, and meat processing waste streams.

Specify Fiber-Reinforced Plastic (FRP) Construction

When the chemical properties and temperature of the process fluid raise concerns about material compatibility, automated scraper strainers are available in other materials such as Monel, D2205, SD2507, and even Fiber-Reinforced Plastic (FRP). The internal mechanism and wetted components can be manufactured from super duplex or similar high-performance steels.

 

Given the wide range of fluids encountered in mining applications, selected materials must resist pH variation, dissolved metals, chlorides, sulfates, abrasiveness, and operating temperatures, while also meeting pressure and flow requirements.

Although standard carbon steel construction is adequate for typical use, corrosive environments such as those involving seawater, erosive slurries, or aggressive chemicals can quickly corrode conventional equipment. This can lead to potential issues in safety, quality, and compliance as well as production downtime, requiring premature strainer component replacement.

For these reasons, duplex or super duplex stainless-steel construction is used to resist corrosion, but at considerable cost. However, a much more cost-effective option is to utilize Fiber-Reinforced Plastic (FRP) strainers that are specifically designed to be resistant to corrosive environments at a fraction of the cost.

Presser points out that FRP can be used for external strainer construction, including for pressure vessel applications up to 300 PSI. The internal mechanism is still manufactured with super duplex or similar steels. With this approach, mining operations can reduce costs by approximately 50 percent or more while maintaining required performance standards.

Easy Field Conversion Between Backwash and Scraper

Most manufacturers of automatic filtration systems commit to either backwash or scraper-style cleaning mechanisms, resulting in equipment that is optimized for only one mode of operation. This often leaves end users with limited flexibility if process conditions change or if the original filtration technology proves to be less effective than anticipated. 

According to Presser, Acme Engineering distinguishes itself by offering automatic filtration equipment that can be readily converted in the field between backwash and scraper operation, without requiring a complete system replacement.

Although Acme’s core design philosophy is centered on scraper-based filtration, its filter housings are engineered from the outset to support both scraper and backwash cleaning assemblies. This design allows the internal cleaning mechanism to be changed using modular components, rather than replacing the entire filter body or piping connections. As a result, operators can transition from one cleaning method to the other with minimal downtime.

This flexibility provides a significant advantage for facilities where operating conditions change over time. It also reduces the risk associated with specifying the wrong filtration technology during the design phase. 

Simplifying Backwash Strainer Upgrades

Although many mining operations would prefer to upgrade their backwash strainers, some are reluctant due to the perception that installation will require extensive and costly piping modifications. These concerns can be addressed by installing custom-engineered pressure vessels and filtration housings manufactured to integrate with existing piping configurations.

“Filtration units can be designed to drop directly into the existing system, which reduces installation labor and minimizes downtime,” says Presser. In many cases, the new filter can be installed during a scheduled maintenance window.

For mining and mineral processors, automatic scraper strainers can offer a far more stable answer to solids separation in applications where conventional screens struggle with heavy loading, changing flow conditions, or persistent fouling. Continuous self-cleaning reduces the need for manual intervention, helping plants avoid unnecessary downtime and maintenance.

For more info, visit Acme Engineering Prod. Inc. at acmeprod.com; phone Philippe Ellison, Project Manager at: +1-518-236-5659; email phil@acmeprod.com; mail Acme at Trimex Building, Route 11, POB 460 PMB 10, Mooers, New York 12958. In Canada phone: +1-514-342-5656; mail them at 5540 Rue Paré, Mont-Royal, QC H4P 2M1.