Glass-reinforced plastic (GRP) pipes’ proven resilience in harsh terrains, extreme climates and unpredictable site environments make them the superior choice over high-density polyethylene (HDPE), steel and ductile iron concrete-lined (DICL) pipes in the demanding environment of a mine dewatering system, according to thermal engineering solution provider Industrial Water Cooling (IWC).

IWC CEO Roger Rusch explains that “unchecked groundwater can affect the stability of the mine stopes and affect the depth of excavation. GRP’s resistance to abrasion from harsh chemicals, including hyper-saline and acidic groundwater, eliminates the need for costly protective pipe coatings and sleeving. These highly flexible pipes also have exceptional creep resistance and resistance to environmental stress cracking, making them suitable for deep-level dewatering operations”.

Rusch stresses that GRP mine dewatering pipes have proven advantages over HDPE pipes – another pipe material regularly used in openpit mine dewatering operations.

He explains that GRP pipes can be manufactured at greater diameters and at a lower cost than HDPE pipes. At these larger diameters, GRP pipes are lighter than HDPE pipes, making them easier and safer to handle. GRP’s hoop tensile strength equates to 300 MPa to 375 MPa, compared with HDPE’s 60 MPa, while GRP’s hoop tensile modulus is 20 000 GPa to 30 000 GPa, contrasting with HDPE’s 5 000 GPa. In addition, GRP pipes can be optimally designed to meet the internal pressure and stiffness requirements of underground piping applications, unlike HDPE pipes.

When compared with steel and DICL pipes, GRP pipes are hydraulically smoother and require a lower pressure head, which reduces overall energy consumption for pumping. Their high strain allowance results in lower transient wave speeds during water hammer events and eliminates the need for expensive water hammer prevention infrastructure.

“Using GRP pipes in mine dewatering systems helps maintain dry conditions, increasing stope stability and ensuring work safety, and offering a cost-competitive alternative to HDPE and metallic materials for these large diameter applications,” says Rusch.