Namibia is set to commission its first cement plant, the new 2 100-t/d turnkey Ohorongo factory, later this year.

Engineering company Polysius was contracted to build the new plant by Ohorongo Cement, a member of German cement company Schwenk Zement. Situated on a 100-ha site, close to Otavi, in northern Namibia, the plant is located near limestone deposits as well as road and railway infrastructure.

The Polysius-Ohorongo agreement, signed in August 2009, stipulated that Polysius would supply all equipment to the cement plant and would also be respon- sible for construction. Ohorongo Cement chairperson and Schwenk group CEO Gerhard Hirth says that the individual parts and the production unit are expected to be commissioned in the fourth quarter of 2010.

Polysius South Africa MD Ralf Hesemann explains that the cement will be stored in three 7 500-t- capacity silos. It will be packed in bags in the cement packing plant, stacked on pallets and covered with shrink wrap. Pulverised coal, produced by a vertical roller mill at a rate of 15 t/h, will fire the plant. The 109-m preheater tower, the tallest building on the site and also one of the tallest buildings in Namibia, is central to the performance of the cement plant.

“The properties of the raw materials and fuels were tested by the Polysius group’s central research centre to ensure correct dimensioning of the preheater/ calciner system, and that all the systems and plant components are harmonised,” Hesemann explains.

The high degree of heat recuperation and the low pressure drop deliver efficiency and availability to ensure increased operation and decreased power and operational costs.

The raw material required for cement production comes from the Sargberg quarry, north of Otavi, which will be the first link in the entire production chain to become operational. Hesemann notes that the 1 500-m-long quarry, with a 12,5-m-high shoulder, which will eventually be deepened to 25 m, will provide the different mineral qualities that will be mined later in the year.

All components of cement, including limestone, which forms 75% of the mined material, marl, shale and calcrete will be mined in their different layers. The first blast took place in March 2010, which prepared the first 600-m2 quarry ground for mining.

A private siding with a shunting locomotive will also be developed on the Sargberg farm to provide direct access to the national railway system and will be instrumental in conveying raw mate- rials and cement products when the plant is in full production.

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