HDPE pipe use in potash mining By Eric Lamontagne, P.Eng., GE Environmental Solutions Inc.
H
igh-density polyethylene pipe (HDPE) has been used in potash mining for well over 30 years.
HDPE pipe can come in many forms, with the most popular by far being the solid wall HDPE pipe. Solid wall HDPE pipe is a continuous and homogenous wall that varies in thickness depending on pressure ratings. This pipe is primarily used for slurry or water conveyance, however, can be utilized with any process piping infrastructure. The resin that is used to manufacture HDPE pipe is continuously advancing, allowing for more design flexibility. These advancements allow for the potash mining processes to become more operationally efficient. The HDPE pipe is already well known in the industry and widely accepted, however, the designing, fusing, and installing is still an area to focus on as a producer. Designing with HDPE pipe
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Each potash site has challenges with new and existing HDPE pipe. requires material engineers to combine knowledge with chemical and civil engineers. This process is crucial to ensure the design with HDPE pipe is suited for each individual site. During the design phase, one characteristic to review is the head loss in fittings. The head loss in fittings can be affected by various fusion characteristics. This includes moulded elbows versus mitered elbows. Mitered elbows are created using the butt fusion process and may have multiple miters which creates additional head loss. Mitered elbows are customizable, however molded elbows provide less head loss but require more space for installation. During process applications such as slurries in potash mining, a considerable amount of time should be dedicated to understanding what pressure surges may occur in the selected HDPE lines. HDPE in comparison to other pipe materials is fatigue resistant primarily due
to two factors. The first factor being that HDPE has a lower stiffness than other pipe materials. The second factor is that the higher-pressure rating required of other pipe materials is generally not required with HDPE to cope with the effects of pressure surges. The area of thermal fusing requires fully trained staff to ensure quality welds. Training is typically provided by distributors and/or fusion machine manufactures. There are currently no third-party training providers for HDPE pipe fusion. The fusion equipment manufacturers require that you are trained with their equipment, however being trained on equipment does not ensure your knowledge of HDPE fusion is sufficient. It is recommended to ensure your training curriculum includes equipment training along with organizations that have extensive knowledge of HDPE pipe fusion techniques and manufacturing processes.
