Mining poses a particularly challenging environment for piping systems and products. DPI Plastics overcomes these challenges in terms of innovation and technology, having met the demanding needs of this industry for over two decades.

Underground mining in particular has to contend with heat and corrosion issues, notes Renier Snyman, technical and product manager at DPI Plastics. “Mining represents a very rugged and uncompromising environment, in which such issues can have a detrimental impact on both productivity and the health and safety of workers.”

DPI Plastics has developed a range of products with specific thermal and physical properties to be able to meet these requirements. The range consists of Mineflo, Drainflo and Airflo, all produced in high-impact PVC-M, and flexible PVC Duroflex mining hose.

“All these products are designed specifically to provide optimum performance in the rigorous mining environment,” Snyman notes. Duroflex mining hose is SABS 1086-certified and is also fully compatible with traditional hose fittings.


The mining hose is SABS-certified and has the added benefit of being fully compatible with traditional hose fittings. This flexible PVC hose range is conveniently colour-coded orange for standard applications, blue for medium duty and green for heavy duty.

Duroflex is longitudinally reinforced with a fluted outer layer for added flexibility. These hoses are ideal for both air and water applications and have a service temperature range of –10°C to 60°C. Additional features include an extended service life, reduced drag resistance, easy handling and minimal stretching.

Mineflo pipes are produced in accordance with the requirements of the SANS 1283 specification for PVC-M pipe for cold water services in underground mining. Pipes are supplied in standard 6.1 m lengths and with pre-assembled steel Victaulic collars.

Ultralok and Minelok

Snyman comments that it is sometimes necessary to cut pipes when performing repairs, or to make up short lengths of pipe, which necessitates the removal of the steel collars. DPI Plastics supplies two products for such applications, namely the Ultralok PVC-M restrained coupling and the Minelok steel repair coupling.

The Ultralok coupling consists of a PVC-M body in two halves, containing metal grip rings, a central rubber seal and six sets of bolts and nuts. The coupling is non-corrosive, quick and easy to install and has a 16 bar maximum pressure rating for use in water pipelines. It is designed to join two plain-ended pipes of the same size, and is available in 105 mm. Snyman adds that a 155 mm size will be made available soon.

Renier Snyman, technical and product manager at DPI Plastics, with Mineflo pipes
Renier Snyman, technical and product manager at DPI Plastics, with Mineflo pipes

The Minelok coupling consists of a coated steel body with a loose metal grip ring. It is designed to join a plain-ended pipe to a Victaulic collared pipe. The coupling is available in 105 mm, 155 mm, 210 mm and 250 mm. It is rated 16 bar for water and 7 bar for air.

Health and safety

Steel Victaulic collars are not supplied loose to mines due to safety reasons. “There is a possibility that the collar may dislodge from the pipe under pressure if it is knocked on by hand. Furthermore, the sealing face of the collar may be damaged, resulting in leaks,” Snyman elaborates.

It is essential that the Mineflo pipe range be supported every 2 m. Supports must be placed in the centre of the pipeline and about 1 m apart on either side of a coupling or fitting. Ideal support methods include metal ‘S’ hooks, chain or steel spreader bars. Valves and fittings require additional support to avoid placing the pipeline under stress.

In order to minimise any external abrasion on the pipe surface, the pipeline must also avoid direct contact with the rockface. The Mineflo range is flexible enough to allow pipe installations to follow slight curves in a haulage way, for example, without the use of additional fittings.

Drainflo and Airflo

Drainflo pipe systems are used in the management of humidity, and fine and aggressive slurries in underground mining haulage ways. The drain contributes to the control of heat loss, and overall safety in the work place.

Airflo pipes from DPI Plastics have been developed in conjunction with various mining engineers to meet the industry’s requirement for a rough, ductile and lightweight pipe for the conveyance of pressurised air in underground mining applications. Airflo pipes are 7 bar (700 kPa) rated for maximum pressure, and are yellow for easy identification.

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