In short. A mining microgrid is a production power plant that happens to sit at the end of a long fuel supply chain. Its sizing is driven by the largest motor start, not the average load; its reliability by dust, heat and maintenance access; and its economics by litres of diesel delivered to site. Batteries and solar can cut fuel and running hours, but only after the crusher, conveyor and pump starting duty has been secured on the generators.
Why mines are a natural microgrid application
Granite and limestone quarries in Telangana, coal and mineral sites in the Godavari belt and remote aggregate operations share a pattern: high operating hours, a weak or absent grid connection, and loads that matter to production every hour they run. Where the DISCOM line exists it is often a long 11 kV spur with frequent trips during the monsoon. That makes on-site generation a primary source rather than a backup, and once generators run for most of the day, the question of whether a battery or a solar array can reduce their fuel and running hours becomes a commercial one worth answering with data. The answer depends on the shape of the load, which in mining is dominated by a few large motors.
The load is a handful of large motors
| Load | Typical behaviour | What it does to the plant |
|---|---|---|
| Primary jaw or cone crusher | Large motor, high inertia, may restart loaded after a trip | Usually sets the minimum online generator capacity |
| Conveyors | Several medium motors, sequenced start | Repeated starting steps through the shift |
| Dewatering pumps | Continuous duty, rises sharply in the monsoon | Critical load; pit flooding stops production |
| Screens and feeders | Vibrating loads, moderate size | Fluctuating demand, poor power factor |
| Workshop, camp and lighting | Mixed single-phase loads | Phase imbalance and the night base load |
| Ventilation (underground) | Safety-critical continuous fans | Cannot be shed; must be on the most reliable source |
The crusher is the sizing case. A direct-on-line start draws six to seven times full-load current at low power factor, and the generator must hold voltage well enough that contactors stay closed and other motors do not stall. Soft starters and VFDs reduce the step, but even with a VFD the online capacity must cover the crusher at full load plus whatever else is running.
S_start ≈ √3 × V × I_LR × k
S_start is the starting kVA demanded, V is line voltage, I_LR is locked-rotor current from the motor data sheet and k is the reduction factor of the starting method (about 1 for direct-on-line, roughly 0.33 for star-delta, lower again for a soft starter set to a current limit). Worked example (illustrative): a 160 kW crusher motor at 415 V with a full-load current near 280 A and locked-rotor current of 6.5 times gives about 1,310 kVA on a direct-on-line start. On star-delta that falls to about 435 kVA, which changes the generator choice entirely. The final figure must be checked against the alternator’s motor-starting curve and the allowable voltage dip. See motor starting on generators.
Where batteries and solar fit
A battery helps a mine in three specific ways. It can supply part of the crusher starting kVA so the generators see a smaller step, which may allow one set fewer to run during the shift. It can act as spinning reserve so a second set does not idle as cover for the first. And it can carry the camp and lighting load at night so the generators shut down entirely between shifts. Solar adds daytime energy that displaces diesel, but quarries are dusty, and panel soiling can take a meaningful share of output unless cleaning is scheduled, so yield assumptions must be derated for the site. Every saving claimed for a mine must come from modelling the actual shift pattern, not from a generic percentage. Generator and BESS systems and off-grid microgrids explain the energy balance behind these figures.
Environment: dust, heat and vibration
Generators at a quarry ingest crusher dust through their radiators and air filters, often at ambient temperatures above 45 °C in April and May. The engineering consequences are concrete. Radiators clog and the set derates or trips on high coolant temperature; air filter restriction rises and the engine loses power; alternator windings collect conductive dust. The response is site design rather than hope: generators placed upwind of the crusher, canopy intakes facing away from haul roads, heavy-duty air cleaners with pre-cleaners, radiator cores with a fin density suited to dust, and a cleaning interval written into the maintenance plan. Inverters and battery containers need the same thinking, with filtered and cooled enclosures rated for the site. A system validated during a mild-weather test proves little about May.
Production-led control and shedding
A mining microgrid controller must know the production sequence, not just the electrical load. If one generator trips, the controller should shed the loads that can stop safely, such as screens or a secondary crusher, while keeping dewatering pumps and ventilation running. It must also prevent loaded conveyors from restarting together after a blackout, because simultaneous restart of every motor is the commonest way to trip a recovering plant a second time. Restart should follow the process: pumps and ventilation first, then conveyors from the discharge end back towards the crusher, then the crusher once the downstream path is clear. Writing that sequence into the controller, and testing it, is as important as the choice of generator. Mining and quarrying power covers the load classes in more detail.
Common mistakes
- Sizing generators for the average shift load. The crusher start dips voltage, contactors drop out and the plant trips every time production restarts.
- Siting the generators downwind of the crusher to shorten the cable run. Radiators clog within weeks and the sets derate in the hottest months when they are needed most.
- Allowing all motors to restart automatically after a blackout. The combined inrush trips the recovering generators and extends the outage.
- Assuming solar yield from clean-panel data. Dust losses cut the expected fuel saving and the business case fails in its first year.
What to send us
Send the motor list with ratings and starting methods, the shift pattern and production sequence, a year of fuel consumption records, photographs of the existing generator location relative to the crusher, and the condition of any grid connection. Note which loads are safety-critical. Send your application details, and see telecom microgrids for a contrasting remote-site case.
Questions engineers ask
Can a battery start our crusher instead of an extra generator?
It can supply part of the starting kVA if the inverter has sufficient short-term overload rating and is designed to share the transient with the generators. The battery’s power rating, not its energy capacity, is what matters for this duty. The combined response must be checked against the motor’s starting requirement.
Should a quarry use one large generator or several smaller ones?
Several smaller sets in parallel usually suit quarries better, because load varies across the shift and one set can stop during low-demand periods. A single large set gives a stronger motor start but runs at poor load factor much of the time and has no redundancy.
How often should generator radiators be cleaned at a crushing site?
Far more often than the standard interval for a clean installation, sometimes weekly in the dry season. Set the interval by inspection: monitor coolant temperature trends and clean before the margin to the alarm shrinks.
Is a grid connection still worth keeping at a mine with its own generators?
Usually yes, even if it is unreliable. Grid energy is normally cheaper than diesel energy, and an islandable microgrid can use it when it is available and run on generators and battery when it is not.
Technical content reviewed by Srinivas Reddy, Managing Partner, Reddy Generators. Last updated 19 October 2026.