Corrosion in pipelines in the mining industry is a very common problem. The inside of pipelines that are required to pump mineral concentrate slurries are subject to contact with corrosion initiating materials. These slurries can include sand, iron ore, potash, limestone, and coal slurries but can vary greatly in their corrosivity and pH. The mining industry unlike other industries with water pipelines has the opportunity to use low quality water in its slurries. Most other industries will utilise high quality water sources for pumping and as such can avoid the issues with the corrosivity of the materials within the water. The types of water that can be used in the mining industry that can cause corrosion include river water, ground water and sea water which can be highly corrosive. The soils used in the slurry itself can also be very corrosive with a wide range of dissolvable salts that can initiate and propagate corrosion as well as significant pH differences depending on the type of soil. The solid can also act as an abrasive, stripping down the paint or metal surface resulting in erosion corrosion. The slurries can be pumped sometimes up to hundreds of kilometres. This means the pipelines have a large footprint for maintenance and inspection routines to ensure correct and safe operation. The pipelines themselves are often made up of a carbon or alloy steel and are susceptible to corrosion. The range of environments that the pipelines are laid in varies greatly from arctic to desert, jungle or marine depending on the location of the material being pumped and the mining operation. This can result in a wide range of working temperatures and humidity environments for the external surface of the pipe work. The consequences of corrosion in pipelines can be catastrophic if left unchecked. Corrosion issues can result in equipment failures, containment breaches and environmental damage like the Prudhoe Bay Oil Pipeline Leak, with 1 million litres of crude oil pumped into the pristine Alaskan wilderness. There are also risks to personnel as in the Perilya Broken Hill Southern Operation accident in 2007. All this can lead to costly repairs for the mining operations and significant investment in remediation works for any contaminated land as well as a damage to public relations and brand.
The use of Inhibispheres corrosion inhibitors in coatings for pipelines can help to prevent or mitigate the effects of corrosion on the steel in pipes. The incorporation of Inhibispheres to replace or supplement traditional corrosion inhibitors can lead to significant gains in corrosion protection and extension in the working life of the coatings. Further reducing down time and maintenance costs for inspection and replacement of parts in corrosive environments. Inhibispheres enhance the corrosion protection of coatings without interfering in the properties of the paint. They are an environmentally benign option for corrosion prevention when compared with chromates and zinc based inhibitors.
Wires are thin strands of metal that have been intricately woven together to provide strong and tough support for industrial work in harsh environments. The corrosion of wires is a function of the exposed area of the wire. The intertwining of the wires increases the surface area of the wires when compared with steel pipe or bars. Wires and cables are often used in the mining industry as static ropes, suspension ropes, running ropes or winding ropes on equipment and infrastructure used in mines and pits. These include ropes and wires for hoist and lifting, draglines, ancillary lines, deep shaft mining, haulage ropes, shovel ropes and ropes for excavators. The wires need to have high tensile strength, ductility and long service life. Lubrication with oils and waxes is often used to aid in the motion of the ropes and combat any frictional forces but also to help prevent corrosion. Corrosion can significantly reduce the working life of a wire or cable. Due to the nature of the work and environment these types of cables are exposed to harsh mechanical environment as well. There can be significant wear and erosion though abrasion. This abrasion can be the wire impacting on other materials or impact on the wire by other materials. There is also the strands of the wire abrading against one another. The wearing down of the wires in combination with the corrosion can lead to serious defects and can result in catastrophic consequences.
The wires, cables and ropes used in the mining industry can be protected from the onset of various types of corrosion through either galvanisation of the wires or by coating with a corrosion protective plastic layer. The wires can also be coated in a lubricant that can contain a corrosion inhibitor to help combat the progress of rusting.
Inhibispheres® can be used to help fight against the onset of corrosion by incorporation in protective coatings for applications like this in the mining sector. Inhibispheres® can be easily incorporated into plastics or oils or waxes as well as all type of standard paint coatings that can be used to prevent corrosion. The use of organic and organometallic corrosion inhibitors is also more efficient and environmentally benign. Incorporation of Inhibispheres® into the corrosion mitigation methods used would allow end users of wires to have greater service life, reduced maintenance and inspection, lower downtime and greater piece of mind when it comes to corrosion.