Modern Mining April 2018

PRODUCT News

Pumps prove themselves on dewatering project

The Acid Mine Water Drainage Scheme is a project to dewater abandoned gold mines in the Johannesburg area. Since the late-19th century, mines startedmoving and followed the gold vein. Many of the original mine shafts near Grootvlei became abandoned and over the years filled with acidic mine water. Persistent rain and rising groundwater caused steadily rising water levels in tunnels and shafts. This has serious implica- tions because the water contains dissolved heavy metals and sulphur. During an earlier phase of the scheme, peristaltic pumps were installed for lime slurry dosing which is used to neutral- ise the acidic water. However, these pumps were expensive to maintain and had a high power consumption. For a new phase of the project, NETZSCH offered a pump package which involved the use of different types of pumps for various applications: NEMO® progressing cavity pumps for polymer dosing and disposal of the gypsum slurry and a TORNADO® rotary lobe pump for the limestone slurry dosing. The TORNADO® is well-suited to the limestone slurry because of its robust design. The hardened steel rotary lobes with a thin rubber inlay work in an elastomer housing. This helps to significantly reduce wear. Service intervals are sub- sequently increased, in some cases by a factor of four. When servicing is being carried out, the rubber housing inlay can be

quickly and easily replaced and at a much more reasonable price than wear plates or a complete housing. NETZSCH, tel (+27 11) 794-8975 website: www.netzsch.com The TORNADO® T2 installed for dosing of limestone slurry.

April 2018  MODERN MINING  51