Q: What is the general attitude of the mining industry in terms of corrosion awareness?
A: Traditionally, mining had exhibited a replacement mentality, because wear and tear from abrasion, not corrosion has been the main life-limiting factor for equipment. That attitude has changed over the last 10 – 15 years to a more sustainable, maintenance based approach, with an increased awareness and understanding of corrosion risk to assets and its associated consequences. In general, the mining industry is behind the times in terms of corrosion prevention, with corrosion control measures generally limited to maintenance painting or coating. Using the coal industry alone as our example, for every 1.0142 billion metric tons of coal produced nationwide, between $62 million and $124 million was spent on maintenance painting or coating for corrosion control. Much of the money currently wasted on outdated measures could have been saved by implementing new technologies.
Q: Due to lower resource prices, the industry in general has been cautious about spending and the budget area that is often first to be reduced is Maintenance. From a corrosion viewpoint, operations may not feel repercussions in the short term, but as time goes on, usually 12 - 18 months, the number of corrosion related failures begin to increase. What should Operations & Maintenance Team keep in mind when developing strategies to prevent future failures under tightening budget constraints?
A: First, managers want to assess areas where corrosion is occurring and take a look at the life cycle and associated repair/replace maintenance costs. Doing so will help them develop a hierarchy of problem areas critical to the success of their operations to make better resource allocation choices. Secondly, I encourage manager to get an understanding of the environment in which corrosion is occurring. It’s important to understand the root causes such as microbially influenced corrosion in the substrate itself as well as identifying environmental factors that contribute to coatings failures. Finally, managers should develop their maintenance strategy and then forecast the long-term (20 years) effects of corrosion vs. maintenance and its effects. By doing so, they can get a clearer picture of how to meet both budget and maintenance objectives in the short- and long-term.
The mining industry tends to rely heavily on past experience and the knowledge of equipment suppliers to resolve any corrosion issues so that production is not interrupted. Engineers with corrosion knowledge and expertise are generally not staff. Because each mine faces its own particular chemical and biological brew of corrosion “triggers”, whenever possible, I would suggest hiring a corrosion consultant to assist in the final assessment.
Q: What area or areas are most obviously or severely impacted by corrosion?
A: The area most commonly impacted by corrosion is infrastructure in the form of not just buildings and conveyors, but also wire rope, critical chains, roof bolts, pumps, electronics, pipes, well screens, dams, bridges and water intakes damaged by environmental factors such as acid mine drainage. Companies, management, government agencies and the general public comprehend that the cost of doing little or nothing about corrosion is unacceptably high: risk of catastrophic failures, as well as repair/replacement of equipment and the associated downtime. Thank goodness the pendulum has begun to swing, and mining has begun to look for new ways to deal with problems specific to corrosion in mining operations in a less “slap-dash” manner.
Q: I keep hearing about microbially influenced corrosion (MIC). Can you briefly explain the phenomenon?
A: The harsh and aggressive conditions in certain mining operations enhance corrosion activity and the use of saline bore water loaded with bacterial life for process water create a naturally inoculated microbially mixed environment. Many sites are experience microbially influenced corrosion (MIC) after less than 12 months. MIC is not usually a single process, but an association and interaction of various microbial types leading to corrosion. MIC can involve a plethora of organisms and mechanisms. Deterioration of materials by living organisms is commonly referred to as biodeterioration, and this phenomenon can encompass both metallic and non-metallic materials (including concrete). MIC is a caused by different microbial types in association with each other and with suitable physical, chemical and electrochemical parameters at or in the metal surface, including sulfate reducing bacteria and bacteria that trap heavy metals such as copper and cadmium within their extracellular polymeric substance, resulting in the formation of ionic concentration cells. Bacteria also produce byproducts that can be corrosive to metals, including inorganic acids, organic acids, sulfides and ammonia.
Case studies implicate MIC in many corrosion failures of critical mine site assets including tanks, rubber lined process equipment, process cooling towers and premature failure of stainless steel reverse osmosis water lines.
The mechanisms involved with MIC can been seen in other types of corrosion. For example, MIC corrosion can rapidly attack metal, and cause pitting corrosion in excess of 5 mm/yr. Microorganisms attack protective metallic and organic coatings exposing the underlying material to corrosion. MIC can also corrode metal due to differential aeration or galvanic corrosion if the protective coating itself is a metal. In addition MIC may alter the composition of corrosion inhibitors, making corrosion control by covering a surface problematic at best. What's more, it's not just from OUTSIDE the metal that MIC attacks, but also from the INSIDE of supposedly clean, blasted metal, too.
Q: Research on MIC on iron and carbon steel had been proposed as early as 1910 and the first theory for MIC mechanisms was suggested during the 1930's (von Wolzogen Kurh & van der Vlugt 1934). This indicates that MIC has been a demonstrated and identifiable problem for at least 70 years. What approaches have been developed to address MIC?
Fungi, aerobic bacteria and organic biocides, biofilm monitoring, electroflotation, organic additives, and barrier plastics have been tried, with varying levels of success. Unfortunately, in all these cases, researchers have a tough time balancing the benefits with a new set of problems each suggested solution has created, which is why we don’t see widespread adoption of these new approaches. In my opinion, CleanWirx is the most practical advance in technology for dealing with MIC. Not only is it effective and ecologically responsible, but it is easy to integrate into industry-wide accepted best practices.
Q: How does CleanWirx fit into corrosion control and prevention strategies in terms of combatting MIC and other forms of corrosion while making the best of tight budgets?
CleanWirx removes microcontaminants, macrocontaminants and reactive sites to prevent flash rusting on surfaces and prepare surfaces for coating. Getting rid of these contaminants makes coatings adhere better so they can do their job in protecting surfaces.
Removing these agents from surfaces prevents formation of reaction sites under the coating from forming and creating reaction sites that penetrate and cause coating failures.
Because CleanWirx is coating neutral, it can be used with virtually any coating system to maximize surface protection surfaces from corrosive elements outside the substrate. CleanWirx does not soften or degrade coatings and has no detrimental effect on even galvanization, inorganic zinc coating or thermal spray metal coatings. Applying a water repellent, high-performance coating that has high resistance to chemicals, biological agents and abrasion, such as ionyx coatings, over CleanWirx treated surfaces will prevent corrosion from occurring above and below the substrate for decades.
CleanWirx integrates into standard corrosion control and prevention strategies easily. Standard strategies involve the following: first, surfaces are blasted to remove debris and existing visible rust. Second, the CleanWirx system is applied to remove MIC contaminants, mill scale and other interference material before coating.
CleanWirx requires no acid washing, so that saves a step. CleanWirx does its job so well, surfaces can be left uncoated for days, which means surfaces do not need to be blasted (or re-blasted) in increments, as is the usual scenario. Prep and coating can be performed in single, uninterrupted stages. Moreover, use of corrosion inhibitors and/or dehumidification is unnecessary when using the CleanWirx system, saving significant time and money in surface preparation.
Surfaces pass inspection prior to coating – the first time. For example, an entire tank can be blasted, treated with CleanWirx and then coated, regardless of its size. This saves time, effort and money, and allows companies to return assets back into service faster.
CleanWirx (step 1) Gel has a dwell time of a mere 30 minutes. Pressure wash the surface with CleanWirx (step 2) Rinse to remove gel and contaminants. Wait 30 minutes or so for surfaces to dry. At that point, coatings may be applied, but – and this is the great thing – coatings do not HAVE to be applied right away. In one specific case, a refinery’s tank was treated with CleanWirx, but it rained for days so the contractor was unable to coat for an interval of several days. All that was required when the rain finally abated was to rinse the surface and let it dry prior to coating – with absolutely no re-blasting needed, as would have been the case had the surface been treated with any other systems.
Q: Besides budget constraints and the problem of dealing with the myriad facets of MIC, you spoke of a third concern: environmental regulations (and by association corporate stewardship). Can Cleanwirx help in this regard?
Yes. CleanWirx is non-toxic and biodegradable. It reduces the use of environmentally harmful impact blasting. The chemicals used in CleanWirx are nor corrosiove to skin and have low to zero VOC (less than 1%), and it requires no “hazmat” shipping. It’s a greener choice for companies across the board. Because it prevents corrosion from under coating surfaces and because coatings adhere better to CleanWirx treated surfaces, there’s a consequentially lower safety and liability risks due to coatings failures. Preventing catastrophic coating failure and employing environmentally safer products whenever possible are the ultimate goals of environmental regulation and corporate stewardship.
Q: Where has this system been implemented, and what have been the results?
Yes, and the result were spectacular. Implementation of CleanWirx on pipelines, offshore platforms, and refinery tanks alone have resulted in huge savings. To briefly illustrate, in a pilot test involving wastewater pipes and drums, one area was treated with CleanWirx, while two similar sites were prepared using conventional methods, then coated using standard epoxy coating. During the eleven-year period of testing (thus far), the Cleanwirx site needed zero maintenance and evidenced no sign of corrosion. The other two sites required remedial maintenance four times due to corrosion issues.
A: First, prevention of corrosion from under coating surfaces is key to facilitating seamless coating protection. Secondly, coatings that adhere better to surfaces suffer fewer failures. These are two areas where CleanWirx technology lessens the detrimental impact of corrosion damage and asset loss on the industry, making it more profitable and safe. Of course, CleanWirx’s ability to lessen the industry’s environmental impact are a major benefit to the industry and the public at large, as I mentioned before, and applies to all new technologies.
Just recently, the Pittsburgh Tribune-Review and Pittsburgh Post-Gazette reported on a Spectra pipeline explosion involving “aggressive, fast-moving” corrosion at pipe welds. New technologies prevent such disasters. CleanWirx improves weld strength by removing reactive sites and contaminants that negatively affect puddling and weld porosity, as well as eliminating weld flame residue and contamination after welds have cooled so coatings adhesion over welds is vastly improved. While this was in the oil and gas industry, it can apply to mining.
In terms of other technologies, it is important to remember that corrosion within the mining industry is corrosion enhanced by abrasion. What makes corrosion control difficult and corrosion prevention more advantageous is that mine atmospheres and waters are unique and vary widely; each mine experiences relatively different corrosion-related problems, including aerobic and anaerobic microorganisms (producing sulfuric acid and hydrogen sulfide, respectively) that make a harsh environment also an extremely corrosive environment.
Technologically advanced high-performance coatings, like the previously mentioned Ionyx coatings, engineered to resist a wide range of possible corrosion factors. Implementing such coatings along with enhanced monitoring technologies benefits the industry by lowering risk and liability, reducing equipment and infrastructure damage requiring repair or replacement, affording leaner operations (with significantly less budget needing to be allocated for coatings maintenance and redundant equipment), and increasing the industry’s ability to prevent corrosion-related failures that negatively impact both the environment and public opinion of the industry.