Crushing is the first place a mine turns ore into money, and the first place it can bleed throughput without anyone noticing until it’s too late. When your primary and secondary crushers are running blind, you’re not just risking downtime. You’re compounding losses across every downstream process that depends on a consistent feed.

A crusher that’s underperforming by 8% doesn’t announce itself. It shows up quietly in your daily tonnage report, already past the point where intervention was easy. Real-time visibility on the right KPIs is what separates a crushing circuit that consistently hits plan from one that’s perpetually catching up. These ten KPIs are the ones that matter most in a crushing operation. Track them live, alert on deviation, and you’ll spend less time explaining shortfalls and more time running the plant.

Crusher Throughput Rate

• Why it Matters: Throughput rate is your crushing circuit’s primary output metric. It tells you immediately whether you’re meeting plan or falling behind, before the gap becomes unrecoverable.
• What it Measures: Tons per hour processed through each crusher stage, measured against a planned rate target.
• What Happens if Missed: Shortfalls accumulate across shifts. A sustained 10% gap can erode weekly production targets in ways that no amount of overtime fully recovers.
• Formula: Actual Throughput (tph) / Target Throughput (tph) × 100
• Indicator Type: Current. This KPI reflects real-time operational output and triggers intervention decisions as conditions change.
• Unit of Measure: % of target (or tph absolute)
• Ideal Visualization(s): Bullet chart against daily target; KPI trend with real-time alerts when throughput drops below threshold; Pareto chart when ranking crushers by deviation from plan.
• Frequency: Real-time (per-minute rolling average)
• Data Required: Belt scale tonnage readings, crusher feed rate, target throughput value per shift plan
• Pro Tip: Compare throughput rate against feed size variability. A throughput dip driven by oversized feed is a drill-and-blast problem, not a crushing problem.
• Red Flag: Throughput trending down while power draw holds steady, which usually points to liner wear or a bridged feed.

Crusher Availability

• Why it Matters: Availability directly caps your production ceiling. An unavailable crusher that wasn’t flagged early is always more expensive to recover than one that was caught on the way down.
• What it Measures: The percentage of scheduled operating time a crusher is mechanically ready to run, excluding planned maintenance windows.
• What Happens if Missed: Unplanned downtime cascades through the circuit fast. A primary that goes down without warning stops everything behind it within minutes.
• Formula: (Scheduled Hours – Unplanned Downtime Hours) / Scheduled Hours × 100
• Indicator Type: Lagging. Availability captures downtime events after they occur, but trending it in real time reveals deterioration patterns before the next failure.
• Unit of Measure: %
• Ideal Visualization(s): Bullet chart against availability target; KPI trend with real-time alerts on status change; Pareto chart when ranking crushers by cumulative unplanned downtime.
• Frequency: Real-time (updated on status change events)
• Data Required: Crusher run/stop status, scheduled hours per shift, fault event timestamps, maintenance mode flags
• Pro Tip: Segment availability losses by cause code (mechanical, electrical, feed starvation, operator). Feed starvation losses that get logged as crusher downtime will distort your maintenance planning.
• Red Flag: Availability tracking above 90% while mean time between stops is decreasing. Short, frequent stops are often a sign of an emerging mechanical issue that isn’t yet tripping a hard fault.

Crusher Power Draw

• Why it Matters: Power draw is one of the best real-time indicators of what’s happening inside a crusher you can’t see. Deviations from the normal operating band expose feed, liner, and mechanical issues before they become failures.
• What it Measures: Instantaneous electrical power consumed by the crusher drive motor, compared to its normal operating envelope.
• What Happens if Missed: Running above the rated power band accelerates liner wear and risks motor overloads. Running consistently below it typically means the crusher is starved or the gap has drifted open.
• Formula: Actual Power Draw (kW) / Rated Motor Power (kW) × 100
• Indicator Type: Current. Power draw responds immediately to changes in feed hardness, size, and crusher mechanical condition.
• Unit of Measure: kW (or % of rated)
• Ideal Visualization(s): KPI trend with real-time alerts on high and low deviations; SPC trend (control chart) to visualize normal operating band and flag statistical anomalies; bullet chart against rated capacity.
• Frequency: Real-time (per-second or per-scan)
• Data Required: Motor current readings, motor voltage, power factor, rated motor nameplate values
• Pro Tip: Establish a normal power envelope per feed material type. A crusher running a harder ore zone should draw more power. If it doesn’t, your feed control may be limiting throughput unnecessarily.
• Red Flag: Rapid power draw spikes followed by sharp drops often indicate liner cracking or a tramp metal event. Treat them as maintenance triggers, not normal process noise.

Closed Side Setting (CSS)

• Why it Matters: CSS defines your product size distribution before you ever measure it. Drifting CSS is the invisible force behind downstream grind inefficiency and classification problems.
• What it Measures: The minimum gap between mantle and concave at the closed position of the crusher cycle, which controls maximum product particle size.
• What Happens if Missed: CSS creep from liner wear produces coarser product than the circuit expects. The SAG or ball mill compensates by grinding harder, drawing more power for the same output.
• Formula: Current CSS (mm) vs. Target CSS (mm)
• Indicator Type: Leading. CSS deviation predicts product size outcomes before particle size analyzers confirm the problem.
• Unit of Measure: mm
• Ideal Visualization(s): KPI trend with real-time alerts when CSS exceeds tolerance band; bullet chart against target CSS setpoint.
• Frequency: Real-time or per-cycle (depending on measurement method)
• Data Required: Hydraulic cylinder position, CSS measurement system output, target CSS setpoint, liner wear compensation offset
• Pro Tip: Track CSS drift rate against liner hours, not just absolute position. A liner wearing faster than expected signals a feed hardness change or an alignment issue worth investigating.
• Red Flag: CSS trending wider than target while throughput appears normal. The crusher is still moving tons, but it’s sending oversize to a downstream circuit that wasn’t designed for it.

Feed Size Distribution (F80)

• Why it Matters: What you feed into the crusher determines what you get out. Oversized feed is the leading cause of throughput loss, blockages, and unplanned stops in a primary crushing circuit.
• What it Measures: The 80th percentile feed particle size entering the crusher, used to confirm the blast and ROM fragmentation are delivering material within crusher design limits.
• What Happens if Missed: Oversized feed drives packing events and bridging, which force manual clearing and stop the circuit. Systematic oversize also accelerates liner wear and increases power draw.
• Formula: F80 (mm) vs. Maximum Feed Size Limit (mm)
• Indicator Type: Leading. F80 data flags a problem that started at the blast before it becomes a crusher problem.
• Unit of Measure: mm
• Ideal Visualization(s): KPI trend with real-time alerts when F80 exceeds crusher design limit; histogram of feed size distribution over a shift window.
• Frequency: Real-time or per-truck cycle (camera/laser-based systems) or per-batch (manual or sample-based)
• Data Required: Feed size analyzer output (camera system or laser profile), crusher maximum feed size specification
• Pro Tip: Map F80 exceedances back to blast blocks and source headings. Recurring oversize from the same area is a fragmentation design problem, and it’s solvable before it repeats.
• Red Flag: F80 within limits but frequent bridging events. Check your feed moisture content. Wet, fine-grained material can pack and arch in the crusher throat even when particle sizing looks acceptable.

Liner Wear Index

• Why it Matters: Liner wear is the primary consumable cost driver in crushing, and it sets a hard deadline on crusher availability. Knowing your wear rate in real time lets you plan changeouts without surprises.
• What it Measures: The estimated remaining liner life based on cumulative tons processed, CSS drift, and wear compensation data relative to the liner’s rated service life.
• What Happens if Missed: Liners run past service life increase the risk of breakage, which converts a planned changeout into an unplanned shutdown with a much longer recovery timeline.
• Formula: Cumulative Tons Processed Since Last Changeout / Rated Liner Life (tons)
• Indicator Type: Lagging. Liner wear accumulates over time, but tracking it continuously drives proactive scheduling rather than reactive failure response.
• Unit of Measure: % of rated liner life consumed
• Ideal Visualization(s): Bullet chart against rated liner life; KPI trend with real-time alerts when liner wear index crosses 80% and 95% thresholds; Pareto chart when ranking multiple crushers by remaining liner life percentage.
• Frequency: Updated per shift (or per material processed)
• Data Required: Cumulative tonnage since last liner changeout, liner manufacturer’s rated life (tons), CSS drift value as a wear proxy, last changeout timestamp
• Pro Tip: Normalize liner life to ore hardness (using Bond Work Index or equivalent) rather than just tons. Harder ore zones will burn through liners faster, and your scheduling should reflect that.
• Red Flag: Liner wear index advancing faster than expected tonnage-per-day would predict. Check your feed sizing. Coarse, hard feed consumes liner life disproportionately compared to well-fragmented feed at the same tonnage.

Circuit Utilization

• Why it Matters: Utilization tells you how much of your scheduled crushing capacity you actually used. It exposes idle time that availability and throughput metrics won’t always surface on their own.
• What it Measures: The percentage of scheduled operating time the crusher is actively processing material, as distinct from being mechanically available but waiting on feed or operator intervention.
• What Happens if Missed: High availability and low utilization is a common combination in undermanaged circuits. The crusher is ready to run; it’s just not running, and nobody is tracking why.
• Formula: Crushing Hours (material in motion) / Scheduled Operating Hours × 100
• Indicator Type: Current. Utilization reflects real-time operational decisions and upstream feed management effectiveness.
• Unit of Measure: %
• Ideal Visualization(s): Bullet chart against utilization target; KPI trend with real-time alerts when utilization drops below acceptable threshold; status history trend to visualize idle and active periods across a shift.
• Frequency: Real-time (updated on feed presence / belt load confirmation)
• Data Required: Crusher run/stop status, belt load or feed presence signal, scheduled hours, idle event timestamps and cause codes
• Pro Tip: Break utilization losses into categories: feed starvation, scheduled maintenance, unplanned downtime, and operator delays. The biggest opportunity for improvement is almost always in feed starvation.
• Red Flag: Utilization consistently dropping in the last two hours of a shift. This often reflects haul truck management decisions rather than a circuit issue, and it’s worth surfacing to the mine planning team.

Vibration Index (Bearing and Drive)

• Why it Matters: Crusher bearings and drive components fail with warning signs that show up in vibration data well before they cause a breakdown. Catching the early-stage signature avoids the most expensive failure modes.
• What it Measures: Vibration amplitude and frequency spectrum from key bearing housings and the crusher drive, compared against established baseline and alarm thresholds.
• What Happens if Missed: Bearing failures in a crusher are rarely clean events. They typically involve secondary damage to the mainframe or drive components, which extends repair time from hours to days.
• Formula: Current RMS Vibration Amplitude (mm/s or g) vs. Baseline and Alarm Limit
• Indicator Type: Leading. Vibration signatures shift before mechanical failure occurs, giving a window for planned intervention.
• Unit of Measure: mm/s RMS (or g peak)
• Ideal Visualization(s): KPI trend with real-time alerts when vibration crosses warning and alarm thresholds; SPC trend (control chart) to identify deviation from normal vibration baseline.
• Frequency: Real-time (continuous or high-frequency sampled)
• Data Required: Accelerometer readings per bearing location, drive vibration sensor output, baseline vibration profiles per operating condition, alarm setpoints
• Pro Tip: Establish separate vibration baselines for different CSS settings and feed conditions. Vibration naturally increases with coarser feed and tighter CSS. Alarming against a single static threshold will produce noise.
• Red Flag: Vibration increasing progressively over multiple shifts without a corresponding change in feed or operational parameters. Progressive increase without a clear cause is a classic early-bearing-failure signature.

Lubrication System Oil Temperature

• Why it Matters: The lubrication system is the life support of a crusher. Oil temperature outside the normal operating band tells you the system is either failing to cool or failing to flow, both of which end badly.
• What it Measures: Supply and return oil temperatures in the crusher lubrication circuit, compared against operating limits defined by the equipment manufacturer.
• What Happens if Missed: Overtemperature operation degrades oil viscosity and accelerates bearing wear. A lubrication failure in a running crusher causes rapid, severe mechanical damage that can write off major components.
• Formula: Current Oil Temperature (°C) vs. High Limit (°C)
• Indicator Type: Current. Temperature responds in real time to changes in crusher load, ambient conditions, and lubrication system performance.
• Unit of Measure: °C
• Ideal Visualization(s): KPI trend with real-time alerts on high temperature deviation; bullet chart against manufacturer’s high temperature limit.
• Frequency: Real-time (continuous)
• Data Required: Supply oil temperature sensor, return oil temperature sensor, ambient temperature, oil cooler status, flow rate confirmation
• Pro Tip: Track the delta between supply and return oil temperature, not just absolute values. A rising delta at constant load often means flow rate is dropping before either temperature reading crosses its alarm limit.
• Red Flag: Return oil temperature consistently running at the top of the normal band during mild ambient conditions. This usually means the oil cooler is fouled and needs cleaning before summer temperatures push it into alarm.

Product Particle Size (P80)

• Why it Matters: P80 is the crusher’s output quality metric. It’s what you’re actually delivering to the grinding circuit, and deviations in either direction cost money downstream.
• What it Measures: The 80th percentile particle size of crushed product leaving the circuit, measured against the target size required by the next process stage.
• What Happens if Missed: Product that’s too coarse overloads the SAG mill and reduces grind efficiency; product that’s too fine can cause classification problems and increase circulating loads in ways that aren’t always obvious.
• Formula: Measured P80 (mm) vs. Target P80 (mm)
• Indicator Type: Current. P80 reflects the combined effect of CSS setting, liner wear, feed characteristics, and crusher performance in a single output value.
• Unit of Measure: mm
• Ideal Visualization(s): KPI trend with real-time alerts when P80 exceeds upper or lower tolerance; bullet chart against target P80; histogram of product size distribution across a shift window.
• Frequency: Real-time or near-real-time (camera/laser-based systems); per hour (sample-based)
• Data Required: Product size analyzer output (or belt camera system), target P80 specification, CSS current value, throughput rate
• Pro Tip: Correlate P80 deviations with CSS and feed hardness data before adjusting settings. Not all P80 exceedances call for the same correction, and the wrong response makes things worse before they get better.
• Red Flag: P80 holding on target while crusher power draw is elevated. You’re achieving the right product size but working harder than you should be to get it, which means liner wear or feed conditions are costing you energy efficiency.

Why Real-Time Visibility Matters

Crushing operations generate a continuous stream of process signals that shift faster than any shift report can capture. When throughput dips, power draw spikes, or a liner approaches end of life, the cost of discovering it four hours later is always higher than the cost of knowing it when it happens. The KPIs above exist precisely because each one represents a decision point: adjust, investigate, or keep running.

The difference between a crushing circuit that consistently meets plan and one that doesn’t is rarely the equipment. It’s whether the operations team has enough real-time context to make fast, correct decisions across the full cycle from feed management to liner changeout scheduling. Visibility is not a luxury in a high-throughput, asset-intensive environment. It’s the operating model.

How Transpara Can Help

If real-time operational visibility is a challenge you’re facing, you’re not alone. At Transpara, we help teams like yours gain clarity from complex systems without the need to centralize or overhaul your data stack.
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