It seems that every aspect of mining is tough – hard rock, blistering temperatures, cyclones and abrasive dust particles.

Venture underground or even to the bottom of the pit then high salinity and acidity are added to the mix. It is little wonder that protective coatings are an essential part of keeping mining operations in production. They play numerous roles to provide barrier protection against these destructive forces, literally from the front gate to the depths of the underground sump.

Given the multitude of environmental and wear challenges faced by fixed plant, mobile equipment and other infrastructure, it is critical that protective coatings are fit for purpose. They must not only be the right type of coating, but their chemical composition must be suited to the specific environment in which they operate. The aggressive ultraviolet (UV) light of Australia is just one example of the many important factors to be considered when choosing an appropriate coating system.

UV rays in Australia are strong and is significantly more damaging than those experienced in Europe and North America. This is why coatings specifically selected and made for Australian conditions is critical for long term durability.

The AMR decided to take a closer look at a number of protective coatings suitable for mining applications, so we contacted Dulux Protective Coatings and spoke to Nick Edwards, the WA state sales manager and Joel Bock, business development executive for mining applications. Nick has spent over 30 years working with industrial coatings and during that time he has worked with countless mining clients to develop tailor made solutions for their protective coating needs. Joel is a certified NACE level 2 coating inspector who has had 10 years of experience in the mining arena.

Advertisement


Polyurea

Polyureas are a class of coatings that have ultra-high build characteristics and offer excellent wear protection. Pure polyureas such as Dulux Flexituff are flexible and have good resistance to abrasion. This make them highly suited to CIL tank internals, chutes, hoppers, rail car internals and other high wear areas.

Specialised spraying equipment is required to apply polyureas as the two-part material needs to be heated and mixed at the tip of the spray gun right before exiting and being applied to the substrate. This chemistry has a rapid curing rate that typically sees plant equipment back in service within 24 hours. When compared to the dry time of conventional coatings, the rapid cure rate of polyurea will reduce potential asset downtime.

Over several decades, Dulux has fine-tuned their polyurea range of coatings for specific applications here in Australia, which are now available as the Flexituff range. Flexituff HP-7, DM-8 and standard Flexituff have different qualities and can to be applied to steel and concrete substrates. Standard Flexituff is designed for use on properly primed concrete and steel with outstanding elongation, meaning it is very flexible.

Flexituff DM-8 is designed for direct application to suitably prepared steel and that is a more abrasive resistant coating than the standard Flexituff.

Flexituff HP-7 is a polyurea hybrid elastomer version in the range that provides a combination of high chemical and abrasion resistance.

This range of high performance polyurea provides the level of chemical, impact, abrasion and corrosion resistance required within the mining industry.

Epoxy

Epoxies are the ‘meat and potatoes’ of protective coatings because they are designed to deal with aggressive exposures such as underground mining, marine and processing facilities. The flagship of the epoxy range is Dulux’s Duremax GFX – a glass flake filled epoxy which provides great resistance to moisture penetration by the layering of glass flakes within the epoxy film.

As the glass flake diagram below illustrates, this layering effect provides a torturous pathway for moisture, making it extremely difficult for water to reach the protected substrate.

It is perfect for coating sheet pilings and associated structural steelwork around jetties and wharves in tidal zones. Being a coating that can be applied without a primer to suitably prepared steelwork in a range of aggressive environments, the coating also offers outstanding surface tolerant properties making it an ideal maintenance coating for onsite applications.

Duremax HBE is a fast cure, high build epoxy, technology favoured by many major mining companies, ports and the marine industry. It provides a high gloss finish and is available in a full range of Australian Standard colours to suit branded equipment, corporate themes, pipelines and critical infrastructure identification. This type of epoxy technology is a high performance product that can handle the fallout from process equipment, the rigours of heavy earthmoving machines and the continuous impacts from ore passing through feeders and screens.

Both Duremax GFX and HBE can be applied in a single coat application up to 500microns to provide superior protective barriers with minimal downtime during the application and return to service process. Each coating can be applied direct to properly prepared carbon steel, galvanized steel and concrete. They can also be over coated with traditional top coat technologies such as polyurethanes and catalysed acrylics, where UV stability is required.

High build, high gloss, epoxy Duremax HBE applied on a screen. Its a go to product in mining due to its fast dry and durability.

Primers

Zincanode zinc rich coatings and Durepon zinc phosphate coatings are designed for specialised protection of carbon steel substrates in aggressive environments.

In the case of Zincanode primers, the addition of zinc pigment into the formula allows the coating to provide a barrier protection to the substrate as well as sacrificial cathodic protection. This range of primers is ideal for freshly abrasive blasted carbon steel allowing for a wide range of epoxies and UV stable top coats to be applied over it.

The range of Durepon primers offers the addition of zinc phosphate pigments, which provides passive inhibitive protection of carbon steel and galvanized steel.

When placed as part of a complete system, Dulux’s primers can provide C4 and C5 corrosion protection dependent upon the particular application and environment. Ultimately these primers are the last line of defence in the fight against corrosion and are typically specified for use in power generation plants, bulk handling equipment’s, oil refineries, mining and chemical processes, offshore structures and exposed pipelines.

UV Stable Top Coats

Aliphatic urethanes are UV stable top coats, typically available in a wide range of colours, with varying levels of finish from matt to gloss. In the mining industry, a gloss sheen is typically preferred. Both Weathermax HBR and Luxathane HPX are gloss urethanes. Weathermax HBR has been locally developed for roller, brush and spray application. They are high build recoatable polyurethanes designed for used over a wide range of suitably primed substrates such as mild steel, galvanized steel, concrete and aluminium.

Weathermax HBR has excellent colour retention and is suited for applications such as pipes, machinery, structural steel, key processing and handling infrastructure and handrails where colour is critical. It was designed to extended asset service time in corrosive industrial and atmospheric marine environments which operates under aggressive UV exposure. This locally developed aliphatic urethane also provides an effective barrier against graffiti and can resists repeated cleaning by most proprietary graffiti removal agents.

Luxathane HPX is a versatile product, suited for new construction and maintenance service over properly primed steel, galvanized steel, aluminium and concrete. It can be used directly over Dulux epoxy primers, universal primers, high-build epoxy intermediate coats and to aged, tightly adhering coatings subject to necessary solvent resistance tests, appropriate compatibility, adhesion, and surface preparation. If required, an accelerator is available for use with standard hardener to promote faster drying.

Both polyurethane options discussed here are suitable for roller application which makes them easy to use in the field. The use of roller can reduce the health impact on workers by minimizing the exposure to vapours and mists of spray applied urethanes. A roller application can protect surrounding infrastructure and surfaces from fallouts associated with spray application.

A fluoropolymer technology, Quantum V90, is a recent addition to the range of Dulux UV stable top coats. This solvent based fluoropolymer option is based on a fluoroethylene vinyl ether (FEVE) resin system that provides the highest level of UV stability and resistance. Each fluoroethylene group consists of three carbon-fluorine bonds. Due to the relative electronegativity of carbon and fluorine atoms, this bond is very polarised, very short and very strong, making these bonds highly resistant to the UV radiation.

This technology is the next step up in providing asset owners with the most robust and high-performance option to protect critical infrastructure against the harsh Australian climate.

With their characteristics of strong colour retention, extensive colour offering, high gloss finish and excellent UV protection, Dulux’s polyurethanes and fluoropolymers are suited to many applications around the mine site from tank externals, to locomotives, earth moving machinery, pipeline identification purposes and hand rails and other important safety equipment.

Fluoropolymer’s chemical and abrasion resistance give this technology an outstanding durability and performance in the mining and heavy industrial sphere. Its anti-graffiti attribute makes it an ideal coating for infrastructure and equipment that is subjected to frequent cleaning and maintenance.

A striking GWA locomotive finished with a coat of catalysed acrylic tinted to an exacting corporate colour. It’s coated again with a clear coat of the same product to provide additional protection against wear and impact.

Australian History

Dulux’s protective coatings have been  selected, designed, formulated and manufactured for Australian conditions. They have proudly worked with partners in almost every industry to develop specific coatings to protect expensive infrastructure and equipment in all the diverse environments this country presents.

Over the years, these coatings have survived Australia’s aggressive UV conditions – UV of a strength and intensity not experienced by countries in Europe or North America.

Their top coats have been shown to withstand breaking down from exposure to UV light over an extended period and prevent the underlying layer(s) from being exposed to the same damaging UV. That is why Dulux’s protective coatings can provide lasting protection of mining assets.

Furthermore, Dulux can recommend specific combinations of corrosion, barrier and UV resistant products to suit different ambient and operating temperatures, varying levels of chemical exposure and abrasion. Their local research and development give end users a wide array of products to provide optimum protection for assets on site.

Dulux Protective Coatings has been manufacturing and supplying heavy duty coating systems in Australia for Australian conditions for over 80 years. These durable coatings and systems meet the chemical resistance, abrasion and impact requirements of the mining industry. With an extensive product range, a tailored solution can be customised for asset owners.

SOURCE
Dulux Protective Coatings
P 08 6465 2672
E joel.bock@dulux.com.au
W www.duluxprotectivecoatings.com.au

Advertisement