CASE STUDY | 12 MW OF POWER AT ONE OF ZIMBABWE'S LARGEST MINES

PROJECT SUMMARY

Location: Guruve District, Zimbabwe
Installed equipment: 12 x HYW 1275 T5 Gensets with YANMAR engines in 20FT containers.
2 x 8MVA / 400-33kV Transformers.
1 x 33kV Switchgear Station housed in a 40FT container .
SCADA/DSE8660 and Control Room
Auxiliaries: 570m3 Fuel farm, Fuel Consumption Management System, LV & HV cabling.

Special Configuration: Advanced diesel “spinning reserve” solution that offers a greater level of reliability of supply to maintain the necessary power levels at the mine, without disruption.
Client: Dallaglio Investments.

Situation & Objective

Delta Gold Zimbabwe is one of the largest mine in Zimbabwe. Although the mine is connected to ZESA through the grid network, Delta required additional power security.
Due to the uncertainty in Zimbabwe as to how reliably the grid will operate, supplementary energy from diesel generator sets, 1MW HIMOINSA generator with Yanmar engine HRYW 1275 D5/6, were required to ensure power continuity in the event of grid outage. A minor outage of only a few minutes can cause the mine hours of production process delays resulting in significant production and financial losses. With Health and Safety of critical importance to the mine the solution had to be fully compliant with all protocols.

SoluTion

HIMOINSA Southern Africa were selected as the turnkey supplier to provide power to the mine after submitting a thorough technical response to a complex technical solution which guaranteed reliable power security.
 The scope includes the integration of the utility supply as well as back-up power diesel generators and on-site operational services. In conjunction with Delta, HIMOINSA Southern Africa developed an advanced diesel “spinning reserve” solution. In the event of multiple and consecutive grid outages, the diesel spinning reserve solution offers a greater level of reliability of supply to maintain the necessary power levels at the mine, without disruption. A SCADA system was installed and integrated to communicate with the grid and the HIMOINSA diesel generators. To avoid any downtime during periods of grid unreliability, the generators run continually at a low load factor, in conjunction with the grid power. 

Should the grid fail, the SCADA system shuts down the power supply to all non-critical parts of mine and the diesel generators pick up the full load of the mines critical process power requirements. Sufficient spinning reserve power is always available to provide the mine's critical power requirements instantaneously.
If there is a prolonged outage, more generators will automatically start so that all the mine's operational power is generated and the HIMOINSA units seamlessly power the mine's full production capabilities. In total HIMOINSA Southern Africa provide 12MW power to the mine to ensure N+1 redundancy.
It is important that the gensets run at their optimum fuel efficiency level and have sufficient spare capacity for peak demand and step-load spikes.

When the utility restarts again, the gensets automatically return to running at the low load spinning reserve. Spinning reserve diesel generation in conjunction with the grid is quite unique. As Health and Safety is a critical value for HIMOINSA Southern Africa and Delta, the HIMOINSA solution encompasses aspects that are not typical for standard applications. For example, when generating power in parallel with the grid it is imperative that there is no chance of back-feed down the line. The SCADA system, plus additional protections, are in place to protect individuals, the mine and the utility from any injury or damage to equipment. A 33kV switchgear has been also provided to integrating the utility supply, the mines transformers and HRYW 1275 D5/6 HIMOINSA generators. Due to the size and potential scope of the mine's operations, HIMOINSA Southern Africa have made sure to futureproof the project by allowing sufficient spare incomers on the switchgear. As the mines power demand grows there is built-in spare capacity which will enable HIMOINSA Southern Africa to easily install additional power supply.

SUPPORT | TURNKEY PROJECT

HIMOINSA will train and educate local Zimbabweans to operate the power plant. Then, at the end of the project term, the day-to-day operations and maintenance can then be passed over wholly, or in conjunction with HIMOINSA Technical Service, to local employees.