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Gas Transport in Underground Coal Mines
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Gas Transport in Underground Coal Mines

Views: 0     Author: Site Editor     Publish Time: 2022-01-07      Origin: Site Inquire

Gas Transport in Underground Coal Mines

Pipeline Material

Mild steel pipes and casing (externally flush) were commonly used since 1940s. They suffer from many drawbacks. Some of them are listed below:

  • 1.Very heavy in large sizes (above 5″ in diameter) and liable to hurt workers.

  • 2.Must be on floor and prone to get damaged by both floor heaving and roof fall. The pipes, often, need wooden support to keep them in alignment.

  • 3.In mines, using DC current for haulage, the steel pipes are corroded by ground current. They need cathodic protection in most cases.

  • 4.They are also vulnerable to chemical corrosion inside the pipeline.

During 1970s, the author first replaced steel pipes by high-density polyethylene (HDPE) pipes that had many advantages as listed below:

  • 1.It is lighter than steel and can be supplied in 20–200 ft length depending on the diameter. A crew of four can easily lay more than 1000 ft in a shift of 8 h compared with about 300 ft for heavy steel pipes.

  • 2.It is noncorrosive. It does not need any cathodic protection.

  • 3.It cannot be punctured by roof falls even if it is closed shut by the falling rocks.

  • 4.It is nonconductive and immune to ground current.

  • 5.It can be laid on floor or preferably hung from the roof.

Below table shows the specifications for some HDPE pipes. Early designs of plastic pipes, such as Aldyl-A by DuPont, were discarded in favor of new HDPE pipes.