Closing every feeder after an outage can overload the power system while delaying the loads that control immediate risk. Restoration uses available power to stabilize safety first, then recover production.
What the restoration plan must resolve
Mine owners, EPC, operations and safety teams responsible for underground ventilation, dewatering, tailings and emergency power.
Combine allowable outage, starting conditions, process interlocks and generator transient capability in one schedule.
Produce criticality levels, dedicated zones, automatic and manual steps, permissives and drill records.
Set priority from outage consequence, then sequence from electrical capability. Equal criticality does not mean simultaneous starting; every step needs permissives, voltage/frequency acceptance, failure action and confirmation.
01
Classify loads by outage consequence
Dewatering, tailings, ventilation, communications and fire systems have different allowable outages. Safety and operations must define consequence together.
- Record allowable outage and escalation point
- Separate people, environment and production consequence
- Identify automatic and operator-confirmed recovery
02
Place critical loads in dedicated zones
Mixing critical equipment with process, camp or workshop loads spreads faults and starting disturbance. Zoning must align with breakers, ATS, busbars and load shedding.
- Draw critical and shed-able circuit boundaries
- Check shared auxiliaries and single failures
- Provide isolation for service and emergency bypass
03
Confirm equipment is ready to start
Pump valves, tailings state, ventilation dampers, lubrication and control supplies can all be permissives. Main power alone may not produce safe operation.
- List mechanical, instrument and control interlocks
- Confirm unloaded or loaded starting condition
- Define manual action if remote signals fail
04
Build a timeline around the largest starting step
State kW/kVA, starting current and duration for each step and compare it with online generation. Start one pump or fan first when required.
- Record steady and transient demand by step
- Require acceptable voltage and frequency before advancing
- Define rollback and retry after failure
05
Validate through an outage drill
Test the sequence under controlled conditions and retain the ATS, breaker, genset, load and alarm timeline. Use results to revise instructions and training.
- Test total outage, unit failure and communication loss
- Retain time-stamped trends and operator actions
- Review after every process or load change
Fields required in the restoration schedule
| Load identity | Area, equipment, feeder, control supply and auxiliaries |
|---|---|
| Consequence | Allowable outage and safety, environmental and production impact |
| Permissives | Valves, dampers, lubrication, level, interlocks and confirmation |
| Electrical step | Steady kW/kVA, start current, duration and voltage dip |
| Logic | Auto/manual, prerequisite, rollback and load shedding |
| Evidence | Timestamps, trends, alarms, operator and revision |
Three unsafe approaches
Starting every critical load together
Equal priority does not prove that simultaneous starting is supportable.
Restoring main equipment only
Missing controls and auxiliaries can prevent safe operation.
Programming without a drill
Real breaker, communications and equipment states may differ from logic drawings.
Information required before integrated testing
- Criticality and allowable outage are approved
- Single-line and field breaker labels agree
- Starting permissives and auxiliaries are complete
- Each step has kW/kVA and starting data
- Rollback, manual takeover and shedding are defined
- The integrated test has permits, recording and review