Mining Pelletizing: AI Vision QC for Audit-Ready

By Grace on June 11, 2026

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The green pellet screen is running 17% oversize. You check the control chart — moisture, disc speed, binder rate all fall within the logged specification bands. Everything looks fine on paper. But the pellets tell a different story, and the audit scheduled for next Thursday will want to know exactly why the oversize rate spiked, when it started, which parameter moved first, and what corrective action was taken. Can your current system answer all four of those questions from timestamped records alone? For most pelletizing supervisors, the honest answer is no. AI vision quality inspection changes that — and it does it at the shift-floor level, not in the quality lab after the fact.

Real-Time Machine Vision · ISO 9001 · Audit-Ready Records · Predictive Defect Alerts
AI Vision QC for Mining Pelletizing: The Supervisor's Playbook for Zero-Defect, Audit-Ready Output
iFactory's AI vision quality platform gives pelletizing supervisors real-time defect detection, adaptive SPC control charts, and automatically generated audit records — so every shift ends with a compliance-ready quality trail and no manual log entry required.
97%+
Defect detection accuracy achievable with deep-learning machine vision on pellet surface and dimensional inspection
60%
Reduction in defect escapes reported by manufacturers deploying AI-driven vision inspection on production lines
100%
Shift-level audit documentation generated automatically — no manual log entry, no missing records at inspection time
40+
Process variables monitored simultaneously across balling, induration, and screening — all traceable to audit records

What AI Vision Quality Inspection Actually Does on a Pelletizing Line

Traditional pellet quality inspection relies on two things: laboratory sampling after induration and operator observation at the screen. Both are retrospective. The lab result comes back after the batch has been committed. The operator sees the oversize rate after the disc has already been running off-target for 20 minutes. AI vision quality inspection operates at a fundamentally different timescale — real-time, continuous, and upstream of the quality consequence rather than downstream of it.

At the balling disc, a high-resolution camera system captures images of the pellet stream at production speed. A deep-learning model — trained on thousands of labelled images of on-spec pellets, joint pellets, crushed pellets, and oversize agglomerates — classifies every pellet in the field of view in real time, generating a continuous size distribution signal that updates the supervisor dashboard every few seconds. This is not a pixel counter or a simple threshold detector. The model learns the visual signature of quality deviations that precede screen rejection, so the alert fires before the oversize rate climbs, not after it is already logged.

How AI Vision Inspection Sees What Manual Inspection Misses — At Every Stage of Pelletizing
Balling Disc
Live Pellet Size Distribution
Camera captures the pellet stream at the disc outlet. The AI model classifies each pellet by diameter band — on-spec, oversize, undersize, joint — updating the size distribution histogram every 5 seconds. The supervisor sees the distribution shift before it reaches the screen.
Induration Furnace
Thermal Profile + Surface Vision
Thermal imaging at the furnace exit detects surface cracking, spalling patterns, and colour variation that correlates with under-firing or temperature excursion. The vision model flags pellet loads at risk of crush strength failure before the mechanical test is run.
Post-Screen QC
Finished Pellet Surface Grading
Final inspection camera grades the finished pellet stream for surface cracks, broken pellets, and shape anomalies that affect tumble index performance. Each inspection result is timestamped and linked to the balling and induration parameters of that production run.

Why Audit Readiness Is the Supervisor's Real Challenge — and Why AI Vision Solves It

An ISO 9001 or IATF 16949 audit does not ask whether your process was in control. It asks whether you can prove it. That proof has to come from records — timestamped, traceable, complete, and available for review without a three-hour manual reconstruction exercise the morning before the auditor arrives. Most pelletizing operations can produce process data. Very few can produce the causal record: which parameter deviated, when was it detected, what corrective action was taken, and was the action effective. The gap between those two things is where audit findings are written.

AI vision quality inspection closes that gap automatically. Every pellet classification event, every adaptive SPC alert, every operator corrective action logged against an alert, and every quality characteristic Cpk calculated across a shift is stored with a timestamp, linked to the recipe and ore blend active at the time, and exportable as a structured audit record. The supervisor does not build this record. The system builds it continuously as the shift runs.

What the Auditor Asks
"Show me the control chart for green pellet moisture on shift 3, last Tuesday, and explain the excursion at 14:22."
"What corrective action was taken when oversize exceeded target on the 06:00 shift and when was it logged?"
"Was the binder batch change on Monday registered before or after the quality deviation that followed it?"
"Provide the Cpk for pellet diameter across the last 30 production shifts with recipe context."
What iFactory Gives You — Automatically
Timestamped adaptive control chart with alert event at 14:22, parameter value, adaptive UCL at the time, and operator action logged against it — exportable in one click.
Predictive alert record with timestamp, oversize forecast trigger, recommended action, operator acknowledgement log, and trend reversal confirmation — all in one event record.
Binder batch change registry with entry timestamp, operator ID, and adaptive limit recalibration log showing exactly when new limits became active relative to the quality event.
Shift-over-shift Cpk report with active recipe tagged to each production run — filterable by grade, ore blend, date range, and operator shift — generated automatically with no manual assembly.
Adaptive SPC · Machine Vision · Shift Documentation · Cpk Reporting
The Audit Record Your Quality Manager Needs Was Generated While Your Operators Were Focused on Running the Line.
iFactory builds the compliance trail automatically — every alert, every corrective action, every Cpk, every recipe change — timestamped and audit-ready without a single manual log entry from the shift floor.

The Three Defect Types AI Vision Catches Before Manual Inspection Can

Pelletizing defects are not random. They fall into three categories, each with a specific visual signature that deep-learning models can detect at production line speed — and each with an upstream process cause that, once detected visually, can be traced back to the parameter deviation that produced it.

Defect Type 01
Surface Cracking and Spalling
Detected at: Furnace Exit

Surface cracks and spalling patterns are the visual evidence of moisture-driven steam expansion inside the pellet during the drying phase. A green pellet entering the induration furnace above the optimal moisture window generates internal steam pressure before adequate sintered strength develops — the surface ruptures, and the pellet either fragments or exits with structural cracks that collapse under tumble index testing. The AI vision model detects crack patterns and spall marks on the pellet surface with sub-millimetre resolution, flagging affected loads before they reach the mechanical test station. The alert links back to the green pellet moisture reading at the time of induration entry, giving the supervisor the root cause with the defect detection rather than requiring separate investigation.

Surface crack detection
Moisture-cause linkage
Tumble index forecast
Defect Type 02
Joint Pellets and Agglomerates
Detected at: Disc Outlet

Joint pellets — two or more individual pellets fused together during balling — are among the most consistent indicators of excess moisture or over-dosed binder at the disc. Their visual signature is distinctive: elongated or irregular shapes with visible fusion lines that no single spherical pellet would produce. Deep-learning segmentation models detect joint pellets with high accuracy even in dense, overlapping pellet streams — a task that traditional edge-detection algorithms handle poorly due to pellet-to-pellet occlusion. The rate of joint pellet detection is a leading indicator for oversize screen output: when joint pellet frequency exceeds threshold, the oversize rate will climb at the screen within minutes. The supervisor gets the warning while the disc parameter adjustment can still prevent the screen exceedance from being recorded.

Agglomerate segmentation
Leading oversize indicator
Moisture-binder root cause
Defect Type 03
Colour and Surface Texture Deviation
Detected at: Post-Induration Screen

Fired pellet surface colour and texture are direct indicators of the degree of sintering achieved in the induration furnace. Under-fired pellets present with a lighter, more porous surface texture that the vision model identifies against the reference profile for correctly fired product at the current recipe and ore blend. Over-fired pellets show darkened surfaces with characteristic surface glazing. Both deviations correlate with crush strength outside specification — and both are detectable by the AI model before the mechanical crush test confirms them. The visual signal precedes the mechanical test result by the time required to conduct sampling and testing, giving the supervisor an actionable window to quarantine the load and investigate the furnace temperature deviation that produced it rather than discovering the failure at the point of shipment review.

Colour deviation grading
Pre-crush strength alert
Temperature-cause linkage

The Supervisor Dashboard: What You See and When You See It

AI vision quality inspection is only as valuable as the information it surfaces to the person who can act on it. The iFactory supervisor dashboard is designed around one principle: the right information, at the right time, in the format that supports an immediate and confident decision. Not data volume. Not statistical complexity. Operational clarity.

Live View
Real-Time Pellet Quality Stream

The live inspection panel shows the current pellet size distribution as a histogram updating every 5 seconds, the defect classification rate for the last 10 minutes broken down by defect type, and a rolling quality score that combines size conformance and surface quality into a single shift KPI. When the distribution shifts toward oversize, the histogram bar extends and changes colour before the screen oversize rate reflects it — giving the supervisor a minimum 10-to-20-minute lead time over the lagging screen measurement.

Supervisor action: Watch the distribution, not just the screen rate. The AI sees the shift before the screen confirms it.
Alert Panel
Predictive Quality Alerts With Root Cause

Every predictive alert fires with a ranked cause and a specific recommended action. The alert does not say "quality deviation detected." It says: "Joint pellet rate rising. Primary driver: moisture at 9.9% — 0.5% above adaptive optimal for current particle size and disc speed combination. Recommended action: reduce moisture addition by 0.3 L/min and monitor size distribution for 5 minutes." The supervisor executes, logs the action against the alert, and the system confirms resolution when the joint pellet rate drops back inside the adaptive band. The alert, the action, and the resolution are all recorded automatically.

Supervisor action: Execute the recommended adjustment, log it in the alert panel, confirm the trend reversal.
Control Charts
Adaptive SPC With Recipe-Aware Limits

The SPC panel shows live control charts for every monitored parameter — moisture, binder rate, disc speed, oversize rate, induration temperature zones — with adaptive UCL and LCL that have already incorporated the current ore blend, binder batch, and active recipe. When a recipe or ore blend change is logged, the limits recalibrate automatically using a rolling data window, eliminating the false alarms that static limits generate during process transitions. Each control chart is exportable as an audit-ready record with the regime context embedded in the chart metadata.

Supervisor action: Log recipe and blend changes in real time. The system handles limit recalibration without manual intervention.
Shift Report
Automatic Audit-Ready Shift Documentation

At shift end, the system generates a complete quality summary: total tonnes produced, oversize rate, defect classification breakdown by type, all predictive alerts fired with their corrective action records, Cpk for every monitored quality characteristic, and a traceability index linking each quality event to the recipe and ore blend active at the time. This report is timestamped, digitally signed by operator ID, and stored in the searchable audit log. The incoming shift supervisor sees the handover state at a glance. The quality manager has the full shift record available for review without requesting it from anyone.

Supervisor action: Review at shift end, hand off the live dashboard. No paper logbook, no manual summary entry required.
"

The audit preparation used to take our quality team two days before every certification review — pulling shift logs, reconstructing corrective action timelines, chasing operators for signatures on paper entries. With iFactory, the audit pack is just there. Every alert, every action, every Cpk from the previous six months, all searchable and exportable in 20 minutes. The last ISO audit went through our pelletizing records with no findings. The auditor actually commented that our process documentation was the most complete they had seen at a plant our size.

— Shift Supervisor, Iron Ore Pelletizing Plant — 3.8 Mtpa, Travelling Grate Induration

Connecting Vision Inspection to SPC: How the Two Systems Work Together

AI vision inspection and adaptive SPC are most powerful when they are connected — not operating as separate tools generating separate alerts, but integrated into a single quality intelligence system where the vision model output feeds the SPC model and vice versa. When the vision model detects a rising joint pellet rate, that signal is fed as a real-time input into the adaptive SPC model monitoring moisture and binder dose. The SPC model cross-correlates the visual defect rate with the upstream process parameters to confirm which parameter is the primary driver, assign a confidence score to the root cause, and fire a single ranked alert rather than two separate alarms from two separate systems.

This integration is what separates a quality monitoring system from a quality intelligence system. Monitoring tells you something happened. Intelligence tells you what caused it, how confident it is in that diagnosis, and what specific action will resolve it — before the downstream consequence is confirmed by a test result or a screen reading.

The Signal Chain: From Vision Detection to Audit Record — in Under 60 Seconds
Step 1
Camera captures pellet stream at disc outlet
Step 2
Deep learning model classifies every pellet in real time
Step 3
Vision output feeds adaptive SPC cross-correlation engine
Step 4
Ranked root cause alert fires to supervisor dashboard
Step 5
Corrective action logged, audit record written automatically

Conclusion

The pelletizing supervisor's quality challenge in 2026 is not a lack of data. It is a lack of interpretation at the right moment and a lack of records in the right format when the auditor arrives. AI vision quality inspection addresses both sides of that challenge simultaneously — detecting defects before they are confirmed by downstream tests, identifying root causes before they require manual investigation, and building the audit record automatically as the shift runs rather than reconstructing it the night before certification review.

For supervisors who are currently managing quality reactively — adjusting disc parameters after the screen oversize rate climbs, explaining shift deviations from incomplete paper logs, preparing for audits by manually assembling records from multiple system exports — the change that AI vision quality inspection delivers is concrete and measurable. Fewer defect escapes, faster root cause identification, lower scrap recycle rates, and a compliance record that is complete, searchable, and exportable at any time without preparation. The technology to run a pelletizing line this way is available today. The supervisors who implement it now will set the quality benchmark that everyone else in the sector is measured against by the end of this decade.

iFactory's AI vision quality platform is purpose-built for pelletizing operations — with deep-learning pellet inspection, adaptive SPC with recipe-aware limits, predictive defect alerts with ranked root causes, and automatic shift documentation that replaces manual log entry. Book a Demo to see the platform configured for your pelletizing circuit, or talk to an expert about a live walkthrough on your process data.

Frequently Asked Questions

The screen oversize rate is a lagging indicator — it reflects the accumulated output of the balling disc over the dwell time between the disc and the screen, typically 15 to 30 minutes depending on plant layout and throughput. By the time the screen oversize rate climbs to trigger an alert under a static SPC system, the process has already been running off-target for the full dwell period. AI vision inspection at the disc outlet classifies the pellet stream continuously and updates the size distribution signal every 5 seconds. When the joint pellet rate or the oversize size band begins to increase, the vision model detects the shift within the first minutes of the deviation — before any material has reached the screen. The lead time advantage over screen-based detection is typically 15 to 25 minutes, which is the full window within which disc parameter adjustments can prevent the oversize from being recorded at the screen and recycled. Talk to an expert about detection latency configuration for your specific plant layout.

The iFactory quality record system is designed to satisfy the documentation and traceability requirements of ISO 9001:2015, IATF 16949:2016, and AS9100 Rev D. The automated shift documentation covers the key record requirements common to all three standards: control chart records with parameter values and limit breach events, corrective action records with timestamps and operator identification, process capability (Cpk) records by quality characteristic, and recipe/input change records linked to quality outcome data. For pelletizing operations supplying the direct reduction and blast furnace markets, the traceability index that links each quality event to the specific ore blend and binder batch active at the time satisfies the material traceability requirements of downstream steel plant quality systems. Book a Demo to review the audit record format with your quality manager before deployment.

The base vision model — which classifies pellets by shape, surface condition, and size band — does not require re-training when ore blend or recipe changes occur. The visual signatures for defect categories (joint pellets, surface cracks, colour deviation, size distribution) are physical characteristics that remain consistent regardless of ore source or recipe. What does update when ore blend or recipe changes are registered is the adaptive SPC baseline — the normal variation range that the process parameter model uses to distinguish genuine defect-causing drift from expected variation under the new process regime. This separation between the vision model (stable across recipe changes) and the SPC model (recipe-aware and adaptive) is a deliberate architecture choice: it means supervisors do not need to manage model retraining cycles when production inputs change, and the system maintains detection accuracy through transitions that would otherwise cause alert noise spikes. Talk to an expert about model management and update processes for your operation.

iFactory integrates with plant DCS and SCADA historians via OPC-UA, OPC-DA, REST API, and MQTT protocols — covering the most common configurations across ABB System 800xA, Siemens PCS 7, Rockwell PlantPAx, and Wonderware historian environments. The camera systems for vision inspection connect to the iFactory edge processing unit via standard industrial Ethernet, with the edge unit handling real-time image classification locally before sending classified event data to the platform. This edge architecture means vision inspection operates at full speed without dependence on cloud latency, and continues to function during network interruptions, with data synchronisation resuming automatically when connectivity is restored. The deployment assessment confirms the specific integration path for your control system before any hardware installation begins. Book a Demo to discuss integration scope with your control systems team.

Every quality event in the iFactory system is tagged with the shift identifier, operator ID, and active process configuration at the time of the event — including the recipe, ore blend batch, and binder batch in use. This means that during an audit review or a quality incident investigation, the supervisor or quality manager can filter the event log by shift, operator, or input configuration and immediately identify whether the deviation was isolated to a specific shift pattern, correlated with a particular ore blend, or linked to a binder batch change. The system does not assign blame — it provides traceable facts that support root cause analysis and, where relevant, demonstrate that corrective actions were taken and were effective. This level of traceability is precisely what distinguishes a well-run quality system from one that can only produce raw process data without context. Talk to an expert about traceability configuration for your shift and operator management structure.

Your Next Audit Should Be the Easiest One You Have Ever Prepared For. AI Vision Quality Makes That the Default, Not the Exception.
iFactory's AI vision quality platform for pelletizing supervisors — deep-learning pellet inspection, adaptive SPC with recipe-aware limits, predictive alerts with ranked causes, and automatic audit-ready shift documentation. See it configured for your process.

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