Moatize Coal Mine I & II Expansion Project

At the mine, a 66kV outdoor substation equipped with a 66kV/22kV transformer which is the main intake supply to the coal complex. In addition to the supply from Matambo, a possible future 40MW power plant will be constructed to feed the main intake substation.

All PLC/DCS/Substation Controller Software and hardware are included in a total automated plant including entire Communication backbone. All MCC’s to run all associated equipment. All field wiring, cabling and racking.

The Coal Mine complex consists of various substations, containerized MCC’s,  mini substations and 22kV overhead lines.

All substations are interconnected via 22kV and fibre optic cables. All 22kV cables are installed underground.

The Moatize Project Expansion covers the expansion of the Moatize Coal Mine with a view to doubling its current production capacity from 11 to 22 million tons of coal on an annual basis, that represents the maximum capacity. The SMES is complemented by the Nacala Corridor Project, which includes a 912km railroad and a port, with the ability to move 18 million tons of coal a year, beyond the capacity of the existing Sena railway line that is already in use.

Overview of scope of works included construct, supply, install and commissioning the electrical reticulation, DCS equipment, MCC’s, instrumentation and communication backbone for the Moatize mine site and included:-

• 22kV SF6 Switchgear;
• 22kV Power Factor and Harmonic Filter system;
• Various 22kV Single Pole ACSR Overhead Lines, complete with Auto Recloser and Sectionalises;
• Various oil filled ONAN Transformers;
• Various 690V 40kA Motor Control Centre’s (MCC’s);
• Various 690V local isolator boxes complete with stop/start pushbuttons;
• Various 400V 15kA Distribution Boards;
• Various 22kV/690V/400V mini substations;
• Various Battery Tripping Units;
• Various uninterruptible power supplies;
• Substation lighting and Small Power System;
• Power and control cables;
• All control room equipment;
• All DCS equipment;
• All software packages required to operate equipment;
• All Fibre Optic communication and Profibus network packages required to operate equipment;
• Power transformers;
• 3 phase 50Hz Mini Substations.

The 66kV transmission line from Matambo to Moatize mine site-wide scope of work included:-

• Extend an existing Substation at Matambo complete with switchgear for a new 220/66kV bay including a 40MVA 220/66kV transformer and the necessary tie in equipment for controls and earthing, including extension to the existing double busbar system.
• Install a 66kV line from Matambo Substation to Tete Moatize site using steel monopoles as well as all the route surveys and soil testing required. The cables to be suitably covered with concrete slabs to complete the installation.
• Build a new switchyard at the proposed Moatize site including all security, lighting and control systems along with a 40MVA 66/22kV transformer.

Contract Value  R209.0 million

Period  February 2014 – November 2016

Site Manhours  828,060

Peak Manpower  325

No. of Transformers 73

No. of NER 36

No of Switchyards (Matambo) 1x220kV

No of Switchyards (Moatle) 1x220kV

No. of Substations 26

No. of MCC/SD Panels 532

No. of 45MVA Transformers 2

No. of 22kV OHL 8

No. of RMU 14

No. of VSD’s  47

PFC Yard 8 bay

B&W returned to the Vale Coal Mine in Tete, Mozambique for a second contract awarded by ABB on behalf of Vale in 2014. The contract involved services for the electrical reticulation network and outdoor switchyards.

Construction complete included:-

• A total of 26 substations;
• 220/22kV Moatize switchyard;
• 220/22kV Matambo switchyard;
• 220/22kV PFC yard;
• Vale 22kV overhead lines;
• 22kV underground cabling;
• Site wide fibre optic cabling for communications and control.

Moatize II required extensive cooperation by all parties on site, being mainly a brown filed construction activity, particularly regarding the trenching for the 22kV cables and optic fibre installation.

From a level 4 programme point of view, trenching and building of the optic fibre manholes became the critical path against the key date schedule mainly due to the extra hard materials to be excavated and in some instances, due to the cable layout, 36% of the trenches were up to 4m wide.

Fibre installation between manholes was through PVC sleeves making attention to detail extremely critical.