Process-Control & Monitoring AI Agent (Processing Plant)
Explain what moved before an excursion, propose a setpoint change with the evidence beside it and check that change against the operating envelope — while the operator and the metallurgist keep every change.
Take the excursion, the alarm event and the tag trend as the control system and the historian hold them.
02
Read the laboratory results, the unit states, the blend that changed and the work done on the circuit.
Reason
03
Assemble what moved before the excursion — which tags, in what order, and which instruments can be trusted.
04
Propose a setpoint change against the circuit's control philosophy, with the trends and samples behind it.
05
Test the proposal against the operating envelope, the constraints in force and the interlocks holding the unit.
Decide
06
Test each reading against its calibration date and its drift and freeze checks, and show what a tag that fails has fed.
07
Route anything touching the envelope, a protective layer or the deposition plan to the metallurgist or the superintendent.
Out
08
Present the account, the proposal and the envelope check as drafts, with the source tags beside them.
09
Draft the shift handover and the unreconciled metallurgical picture, and retain every operator amendment.
→Product statement
The agent watches, explains, proposes and checks. Writing a setpoint, changing a loop mode, moving an alarm limit and authorising a deposition stay with the named person.
Example workflow
One excursion, end to end
AgentHuman
1Excursion detectedA tag leaves its normal band, an alarm is raised, or an operator asks what is happening to a circuit
2Plant data gatheredTag trends either side of it, laboratory results, unit states, the blend that changed and work done on the circuit
3Account assembledWhat moved, in what order, and which of it the instruments can actually be trusted on
4Proposal checkedA setpoint change tested against the operating envelope, the constraints in force and the interlocks holding the unit
No human action required
Stages 1 to 4 run without a person in the loop — detection, gathering and the envelope check finish before anyone is asked to read anything. Nothing on the plant changes in that stretch.
5DecisionSplits on analysis confidence and whether the envelope or a protective layer is involved
Inside the envelope, instruments healthy
Reaches the operator as a complete account.
Envelope, interlock or deposition involved
Goes to the metallurgist before it goes further.
Control-room operator or metallurgist
Reads the account, the evidence, the envelope check and what is unresolved, then decides whether anything on the plant changes.
Accept account · Amend · Escalate
Account accepted — handed back▼
6Handed to the control roomPresented to the operator as a proposal; no setpoint, loop mode, alarm or deposition is changed by the agent
7Outcome evaluatedWhat the operator amended, what the shift review concluded, and what the reconciled balance later showed
Amendments
What the operator corrects at the desk is counted in the evaluation.
What should not run autonomously
Human approval stays in control
Outside the boundary — human approval required8 items
Writing a setpoint to the control system.
Putting a loop in or out of automatic.
Starting, stopping or isolating any unit.
Acknowledging, shelving or suppressing an alarm.
Automation boundaryAgent acts unaided
✓Explain an excursion and what moved in the hours before it.
✓Propose a setpoint change with the evidence behind it.
✓Test a proposal against the operating envelope and the constraints in force.
✓Draft the shift handover and the unreconciled metallurgical picture.
Write actions run only inside the approval boundaries agreed during implementation. A setpoint is never one of them.
Changing an alarm limit or a trip setting.
Overriding an interlock or a permissive.
Authorising a deposition, a discharge or a transfer.
Signing a metallurgical balance or a production figure.
Example output
One excursion, annotated
Everything the agent proposes is attached to the tags, the samples and the shift it came from.
Excursion account · one circuit, one shiftIllustrative example
Excursion as raised
Circuit
Envelope rev
Proposed
Confidence
Setpoint
Rougher circuit out of band
Flotation, after a blend change
Rev 8
Setpoint change, for review
84%
Not written by the agent
As receivedThe excursion as the control system raised it, the circuit it sits in and the envelope revision current at that moment.
Evidence usedTag trends either sideShift composite assayBlend and reagent change
Why it stops hereThe proposal sits inside the envelope, but the analyser feeding it is past calibration.
ActionAccept accountAmendEscalate
What the score decidesConfidence decides how hard the operator reads this, not whether the setpoint moves.
Value
Where AI adds value
The same four claims, placed at the point in the workflow where each one applies.
Where the value landsValue 01 – 04
Every excursion the plant raisesFrom the control system and the historian
03Analysis & proposal
Read the circuit's own limits
Use the control philosophy for that unit, the operating envelope, the constraints in force this shift and the interlocks holding it.
01Approved path
Explain the excursion, not just flag it
The trends, the laboratory results, the blend change and the work done arrive as one account, while the shift still has room to act on it.
02Human review
Send the envelope case up, not out
A proposal that sits outside the envelope, and anything reading against the deposition plan, goes to the metallurgist and the superintendent rather than onto a control-room screen.
04Build an evidence trail
Retain the tags and samples read, the envelope revision, the proposal, the confidence and every operator amendment — on both paths.
Integrations
Typical integrations
Five system groups connect to the same agent. Which of them are in scope is decided in discovery.
Control & historianDCS · PLC · SCADA Process historians · OPC UA
Integration availability depends on the client's existing systems and API access.
Agent controls
Six layers between the model and the control system
Each control wraps the one inside it. A proposal clears every layer before an operator reads it, and writing it to the plant sits outside all six.
L6 · Outermost — last line of defenceInward → L1 · closest to the model
L6Rollback / safe modeReturn analysis to the control room and the metallurgist if evaluations or production signals degrade.Roll back
L5Change controlRecord the tags and samples read, the envelope revision, the proposal, the named approver and every operator amendment.Record
L4No-write boundaryThe agent holds no write path to a setpoint, a loop mode, an alarm, an interlock or the deposition system, and nothing it raises is annunciated as a plant alarm.Hold
L3Envelope checkA proposal is tested against the envelope revision, the constraints in force and the permissives holding the unit; anything that fails is held and shown held.Stop
L2Instrument healthReadings are tested against calibration date, drift and freeze checks; a tag that fails is marked suspect and the operator is shown what it fed.Test
L1Tag and source checkNumbers carry the tag, the time and the sample they were read from, and what the agent could not resolve is shown as unresolved rather than filled in.Cite
Model coreAccount assembled — what moved, the proposal, the envelope check and confidence
L1 – L2Decide whether a reading may be trusted
L3Decides whether a proposal may stand
L4 – L5Keep the change with a person and the record intact
L6Pulls automation back when signals degrade
How Nestack evaluates it
Evaluate the whole account — not only the proposal an operator reads.
Coverage runs the whole depth of the workflow, and every layer is cut by slice.
Surface — the account the operator opens
Depth of coverage ▼
E1Final-output evaluationWas the account right about what actually moved, and in what order?
E2Step-level evaluationDid it read the current envelope, constraint and control philosophy?
E3Tool evaluationDid it resolve the correct tag, unit and laboratory sample?
E4Envelope recallHow many proposals against the envelope or a protective layer were held?
E5Slice evaluationHow does account quality change across specific excursion cohorts?
E6Business outcomeWhat did the operator amend, and what did the shift review find?
Floor — what the shift review and the balance later showed
Failure modes
Where each failure originates in the agent
Seven failure modes plotted against the five stages of the agent lifecycle.
Agent lifecycleDirection of processing →
01 · Retrieval2 modes
PC-01
Drifting analyser read as ore
A slow instrument drift is explained as a change in the feed.
PC-02
Deposition reading read as ordinary
A pond, beach or freeboard reading outside the plan is shown as normal movement.
Stage gathersTag trends, laboratory results, states and the envelope
02 · Analysis2 modes
PC-03
Correlation given a direction
Two tags that moved together are presented as cause and effect.
PC-04
Proposal built on a stale envelope
The envelope revision used was superseded at the last change.
Stage proposesWhat moved, in what order, and the setpoint to consider
03 · Envelope check1 mode
PC-05
Permissive not read into the check
A proposal assumes a unit that a permissive is holding out.
Stage checksThe envelope, the constraints and the interlocks in force
04 · Handoff / write1 mode
PC-06
Output adds to the operator's load
So much is raised beside the alarm system in an upset that it stops being read.
Stage presentsThe account the operator reads and where it sits
05 · Change / Version1 mode
PC-07
Philosophy change untracked
An envelope or control-philosophy change reaches the agent with no named approver.
Stage tracksModel, prompt, envelope and philosophy changes
Sev-1 · plant or a protective layer is exposedSev-2 · a wrong account reaches the operatorSev-3 · analysis degrades, more is amended
The hours after the ore changes are where this fails
Most of a shift is steady state on a familiar blend and those accounts hold up. The hours after a feed change do not, nor does a circuit whose analyser has drifted, nor a plant in upset. Nestack reports performance by slice, not only in total.
Slice performance — reported separately, not only in aggregateIllustrative example
Slice
Failure rate
Lift
Lift vs. threshold
Status
Hours after a blend change
4.8%
3.0×
Review
Circuits with a drifting analyser
3.4%
2.1×
Review
Plant already in an upset
2.9%
1.8×
Watch
Steady state, familiar blend
1.3%
0.8×
Normal
Bar: amended-or-withdrawn account rate, lift vs. steady-state baseline · scale 0–4.0× · tick marks the 2.0× review threshold2 of 4 slices over threshold
Evidence-linked improvement
A setpoint that worked once is not an explanation
Amending the account for one shift leaves the reason it read wrong in place. What changes is the tag it trusted, the envelope, or the rule that raised it.
Improvement cycle · five stagesSwitchback — the path turns at Improve and returns at Learn
01Detect
Operator amendments or shift-review findings move in a cohort.
02Diagnose
The shift review already named the cause; the question is which tag the agent trusted to get somewhere else.
03Improve
The tag rule or envelope reference goes through management of change, with an approver.
04Verify
Replayed over past excursions the plant has already reviewed to a cause.
05Learn
The excursion is kept for replay and the philosophy note the operators read is amended.
Learn → DetectThe return edge. An operating envelope or a control philosophy is changed under management of change, never by the agent.
Typical build scope
Twelve workstreams across six weeks
The build scope read against the delivery timeline. Week structure follows the six-week plan — discovery, plant data sources, analysis and envelope logic, evaluation, integration, then production validation and handover.
WorkstreamWeek 1Week 2Week 3Week 4Week 5Week 6
01Workflow discovery and automation-boundary definition.
02Control-room and shift-handover assessment.
03Operating envelope and constraint capture.
04Historian, analyser and LIMS data access.
05Excursion detection and account assembly.
06Setpoint proposals and evidence linking.
07Instrument-health and drift marking.
08Envelope, constraint and deposition checks.
09Evaluation suite, envelope recall and regression cases.
10Operator review and amendment capture.
11Handover and metallurgical-picture drafting.
12Observability, deployment and Agent Care handover.
12 workstreams · 6 weeks · bar shows the weeks a workstream is active — several run in parallelFinal scope and sequence confirmed in discovery
Engagement tiers
What each tier includes
Rows are the capabilities named in each tier's scope. Higher tiers include everything below them.
Capability✓ in scope · — not at this tierPilotOne circuit, one plantProductionProduction control-room integrationAdvancedMulti-plant / multi-circuit
Introduced at Pilot
Excursion accounts from your own historian✓✓✓
Setpoint proposals with the evidence attached✓✓✓
Operating-envelope and constraint checking✓✓✓
Calibration, drift and freeze tests on each tag✓✓✓
Deposition limits read, never proposed against✓✓✓
No write path to a setpoint, mode or alarm✓✓✓
Baseline evaluation✓✓✓
Introduced at Production
Operator review workflow and shift handover—✓✓
Observability and evaluation—✓✓
Introduced at Advanced
Multiple plants, circuits and control systems——✓
Group reporting and enterprise controls——✓
Build priceFrom $5,000From $8,000Custom quote
Final build priceConfirmed after discovery based on the control and historian systems in scope, the number of circuits and plants, analyser and laboratory sources, approval controls and deployment requirements.
Separate from buildBuild pricing is separate from recurring Agent Care, which covers managed monitoring, evaluations, incidents and verified improvements after launch.
What we need from you
What you bring, and what we build with it
Each input maps to a piece of build scope and a week in the delivery timeline.
You bringWe build with it
01Your control philosophy and the envelope each circuit runs to→Operating envelope and constraint captureWeek 1
02How an excursion reaches your control room today, and who acts→Control-room and shift-handover assessmentWeek 1
03Access to the historian, the online analysers and the LIMS→Historian, analyser and LIMS data accessWeek 2
04Your calibration records and which tags you already distrust→Instrument-health and drift markingWeek 3
05Your deposition plan, its limits and who is told when one moves→Envelope, constraint and deposition checksWeek 4
06Excursions you have already reviewed to a cause→Evaluation suite, envelope recall and regression casesWeek 4
07Named operators and a metallurgist to review accounts→Operator review workflow, then pilot shifts and production validationWeeks 5–6
Nothing else is requiredDeployment, documentation and Agent Care handover are ours.
Delivery timeline
Four phases across six weeks
Phases are drawn over the weeks they actually occupy. Week 5 carries both the evaluation work and the first shifts an operator reads accounts on.
PhaseW1W2W3W4W5W6
DiscoveryW1
BuildW2 – W3
EvaluateW4 – W5
Pilot & LaunchW5 – W6
Week focusW1Control philosophy, the envelope and the automation boundaryW2Historian, analyser and laboratory sources wired inW3Excursion accounts and setpoint proposals on the first circuitW4Evaluation suite, envelope recall and instrument-drift testsW5Control-room presentation, supervised shifts and correctionsW6Operators read live accounts beside their own board, then Agent Care starts
Reading the bandThe envelope and instrument-health tests come before anything is put in front of an operator. Week 4 exists so that week 5 is not the first time either is checked.
At the end of W6Operators have read live accounts against their own board and the metallurgist has amended what did not survive the shift review, then Agent Care takes over monitoring.
DurationSix-week plan shown · typical delivery 4–6 weeks depending on scope confirmed in discovery.
Next step · Mining AI agent
Build a process-control agent around your control room.
Show us one circuit, the envelope it runs to and how an excursion is written up today. That excursion then has two accounts, the shift's and the agent's, and you decide which of them read the instruments and which one guessed.
