Two road tankers, one in the foreground and one on the far right of this scene, being filled simultaneously in the silo’s ground-level loading bays.

Air-slides to the top of the silo compartments and one of four dust filters (RHS) under the silo roof.

Cement silo for NPC, Durban

Bateman Materials Handling has supplied a four compartment BATEMAN Ibau silo with a capacity of 14 000 tonne to Natal Portland Cement (Pty) Ltd, Durban, RSA. It receives four types of cement from a nearby blending plant and they are loaded into road trucks underneath the silo for distribution.

Located in an urban residential area near a nature reserve, it had to comply with several City Council requirements and be architecturally pleasing. Its multi-cell configuration was ideal for the minimal space available.

Materials handling

The silo holds 14 000 tonne of product, has a 20 m diameter and is 68 m high. Featuring Ibau technology, it is equipped with two 250 t/h mobile loaders and weigh bridges for road tanker out loading. Four storeys of floor space, incorporating the control room, are located underneath the silo within the confines of its wall. A man lift and staircase provide access to the silo roof.

Two bucket elevators (with lifts of 50 m and 30 m) capable of handling 200 t/h receive the cement, transfer it to the top of the silo or recycle it between cells. Approximately 500 m of BATEMAN Ibau extraction air-slides in the silo compartments ensure the release of the cement. Two interconnecting gantries equipped with BATEMAN Ibau transport air-slides join the silo to the main plant. Materials flow from the silo is controlled using 15 BATEMAN Ibau flow control gates.

Environmental care

Dedusting filters are installed around the plant to prevent release of cement dust to the atmosphere. The large blowers and compressor, housed in rooms alongside the silo, are fitted with acoustic canopies to maximise noise suppression.

Control system

The silo is driven by a programmable logic controller (PLC) tied to the computer system of the existing blending, milling and materials handling plants.

A turnkey project

Initially a design contract, it was converted into a turnkey project. BATEMAN undertook the civil, mechanical and electrical engineering design and erected the steelwork, which was manufactured in BATEMAN’s Gauteng workshop and transported to site. Besides the civil engineering design, more than 600 mechanical engineering drawings and 640 electrical engineering drawings were prepared. Over 4 000 m³ of concrete, 600 tonne of reinforcement steel and 200 tonne of structural steel were used to construct the silo. The steelwork and bucket elevators were manufactured in BATEMAN’s workshop in Gauteng and transported to Durban. Commissioning was successfully accomplished on schedule during a six week period.

For more information, kindly contact David Gale, Manager, Pneumatics, on Tel. +27-11-201-2300 or email

engtech@batemanengineering.com

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