The Problem
Mining operations are among the most electrically intensive environments on the planet. Large grinding mills and crushers at the MV level create a hostile harmonic environment that cascades through the entire site, but the real daily cost is paid at the low-voltage level — conveyor drives, pump stations, processing auxiliaries, ventilation fans, compressed air systems, dewatering pumps, and camp power. These LV loads suffer power factors below 0.80, voltage THD above 8%, and chronic equipment failures.
What Causes It
Large grinding mills (2–25 MW) driven by cycloconverters generate not just standard harmonics but interharmonics — distortion at non-integer multiples of 50/60 Hz. This distortion propagates through step-down transformers to the LV distribution network, where it combines with harmonics from VFD-driven conveyors and processing equipment. Hoists and winders create massive cyclic demand swings. Crushers produce severe starting transients that depress voltage site-wide.
Why traditional filters fail in mining + Read more− Close
Tuned passive filters are designed for specific harmonic orders (typically 5th and 7th from 6-pulse rectifiers). But cycloconverter-driven mills produce a continuously varying spectrum including interharmonics that fall between standard orders. Temperature and ageing cause detuning over time. And large reactive power swings from hoists and crushers create resonance risk with any passive filter. Only active, software-controlled compensation can track and cancel this dynamic spectrum in real time.
The Solution
HarmoniQ deploys at the low-voltage (≤600V) distribution level — motor control centres, conveyor drives, pump stations, and processing auxiliaries. Its narrowband tuning technology samples 20,000 times per second and dynamically compensates for the chaotic harmonic environment that MV mill loads inject into the LV network.
A medium-voltage product (up to 14kV) is in development for direct deployment on large mill and crusher circuits.
Tracks and cancels the dynamic harmonic spectrum from cycloconverters, rectifiers, and VFDs in real time — including the interharmonics that passive filters miss. Reduces THD below 5% at the point of common coupling.
Stabilises voltage during crusher starts, hoist cycling, and mill load variations with 20,000 impedance adjustments per second. Protects SCADA, protection relays, and process control from false trips and lost production.
Drives power factor from 0.65–0.80 to 0.98+, eliminating massive reactive power flows. Responds dynamically to rapid PF variations from cyclic loads — unlike capacitor banks that only correct at the meter point.
The Impact
| Metric | Before | After HarmoniQ | Improvement |
|---|---|---|---|
| Power factor | 0.74 | 0.98 | +32.4% |
| Voltage THD | 8.2% | 3.1% | −62% |
| Annual electricity cost | $15,900,000 | $13,650,000 | −$2,200,000 |
Every facility is different. Our engineers will model the exact savings, deployment costs, and timeline for your specific site — get in touch for a free, no-obligation assessment.
Beyond the Bill
Mill motor rewinds cost $255,000–$635,000 each. Clean power extends motor, transformer, and drive life by 20–35%, deferring capital expenditure and reducing unplanned downtime.
A 25 MW mine saves approximately 1,080 tonnes of CO₂ per year — supporting ICMM net-zero commitments and the ESG credentials that increasingly determine your social licence to operate.