Marshall Girtman discusses overcoming materials degradation of cable couplers due to prolonged ultraviolet exposure
Ultraviolet (UV) exposure often causes material deterioration for cable couplers that are exposed to sunlight for prolonged periods of time. Although this isn’t an issue for below-ground mining operations, above-ground applications are particularly susceptible to these harmful rays and their damaging effects.
UV radiation is a form of electromagnetic radiation that is emitted through sunlight. Excessive exposure to UV radiation can lead to materials degradation of a variety of polymers, including various types of rubber and plastics. Early effects of UV exposure may result in colour fading and discolouration. However, prolonged exposure to UV radiation may result in further material degradation, to include cracking and breaking, and eventual disintegration. The actual effects of UV exposure vary depending on the type of polymer, as well as the time and intensity of exposure.
Above-ground mining operations are particularly susceptible to this material degradation due to UV, particularly at high altitudes. For instance, several mining operations located in South America are open-pit mines, which operate at an elevation of over 4,700m (15,420ft). These mining operations are frequently exposed to harmful UV radiation, and at a higher intensity due to the increased elevation than other mining operations. As a result, many of the cable couplers used in these operations experience significant material degradation due to UV exposure for prolonged periods of time.
This materials degradation due to UV exposure poses a serious safety issue for cable couplers. Since these materials are often used to insulate electrical current, there are several possible issues when they degrade. As the polymers break down due to UV exposure, the chemical composition degrades, which often causes the insulation resistance to drop below sustainable levels. This increases the chance for current drops throughout critical equipment applications. Additionally, if the materials in the couplers crack and break, this can lead to the exposure of electrical wires and increase the chance of electrical shock. Even fading colours can pose a safety risk, as many cable couplers are colour-coded to specific currents and voltages.
What Is The Solution?
To overcome the dangers associated with UV materials degradation, SMS Connectors has developed specially formulated rubber compounds for use in all of the company’s products. These compounds have recently been independently tested by Underwriters Laboratories (UL), specifically in regards to degradation caused by ultraviolet radiation. Upon a thorough analysis of all of the proprietary rubber compounds used to manufacture the connectors, it has been determined that they exhibit no negative effects due to prolonged exposure by UV radiation.
These findings by UL are critically important in several applications of the connectors. These products have successfully been used for many years in underground mining applications and have recently gained in popularity for above-ground mining applications. Accordingly, the proven UV resistance of the connectors makes them an essential component for above-ground mining applications as a reliable source to provide safe and efficient energy to power a variety of equipment.
Marshall Girtman is with Special Mine Services