Overview
The concentrate of the ore is mixed with water and then pumped over a long distance to a port where it can be shipped for further processing. At the end of the pipeline, the material is separated from the slurry in a filter press to remove the water. Water is usually subject to a waste treatment process before disposal or return to the mine. Slurry pipelines offer an economic advantage over railroad and much less noise disturbance to the environment, particularly when mines are in extremely remote areas.
Pipelines must be suitably engineered to resist abrasion from the solids as well as corrosion from the soil. Some of these pipelines are lined with high-density polyethylene (HDPE).
Typical materials that are transferred using slurry pipelines include coal, copper, iron, and phosphate concentrates, limestone, lead, zinc, nickel, bauxite and oil sands.
Slurry pipelines are also used to transport tailings from a mineral processing plant after that the ore has been processed to dispose of the remaining rocks or clays.
For oil sand plants, a mixture of oil sand and water may be pumped over a long distance to release the bitumen by attrition. These pipelines are also called Hydrotransport Pipelines.
The 85km Savage River Slurry pipeline in Tasmania, Australia, was possibly the world's first slurry pipeline when it was built in 1967. It includes a 366m bridge span at 167m above the Savage River. It carries iron ore slurry from the Savage River open cut mine owned by Australian Bulk Minerals and is still operational as of 2011.
One of the longest slurry pipelines was to be the proposed ETSI pipeline, to transport coal over a distance of 1036 miles (1675 km). It was never commissioned. It is anticipated that in the next few years some long distance slurry pipelines will be constructed in Australia and South America where mineral deposits are often a few hundred kilometers away from shipping ports.
A 525km slurry pipeline is planned for the Minas-Rio iron ore mine in Brazil.
Slurry pipelines are also considered to de-silt or remove silts from deposits behind dams in man-made lakes. After the Hurricane Katrina disaster there have been proposals to pump silt to the shore and remedy the environment. Proposals have also been made to de-silt Lake Nubia-Nasser in Egypt and Sudan by slurry pipelines as Egypt is now deprived of 95% of its alluvium that used to come every year. These projects to remedy the environment will be very beneficial to the damage caused by large dams and man-made lakes.
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