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Glossary

Plain-language definitions of terms we use in our work

321 of 321 terms

A

Action limitMaintenance and reliability
The value of a measured condition at which maintenance work is done at the next planned opportunity, set to leave enough remaining life to plan, schedule and do the work. It sits between an alert limit, which says look closer, and a minimum or stop limit.
Used in: Condition based maintenance: the triggers, the limits every condition task needs, planning from the trend, and turning a crossed limit into planned work
AddendumMechanical and structural
A formal change or clarification to tender documents issued to every tenderer during the tender period, often recording the answer to a question. Tenderers acknowledge each addendum on the form of tender.
Used in: Tender documents and the tender process: what goes in a request for tender, what tenderers return, evaluation criteria, and what causes trouble later
Affinity lawsMechanical and structural
The relations for a centrifugal pump or fan when speed changes: flow in proportion to speed, head with speed squared, power with speed cubed.
Used in: Centrifugal pumps and pump curves: the operating point, best efficiency point, affinity laws, cavitation and NPSH, and running in the wrong place
Alarm floodData and software
A period in which alarms arrive faster than an operator can read and act on them, usually defined as more than ten alarms in ten minutes per operator console. Floods follow trips and upsets, when one cause produces many consequential alarms, and the one alarm that says what to do is buried among them.
Used in: Alarm management: the lifecycle, rationalisation and the measures, with a worksheet
Alarm rationalisationData and software
The review of every candidate alarm against the site's alarm philosophy: its cause, the consequence of no action, the operator's action, the time to respond, and from those its priority and setpoint. An alarm with no operator action is removed. The output is the master alarm database. ISA-18.2 and IEC 62682 describe it as the gate in the alarm management lifecycle.
Used in: High performance HMI: screens that show the operator what is abnormal, the display hierarchy, and the ISA-101 life cycle, Control system design documents: the chain from the P&ID to the code, and the two the tests run from, Alarm management: the lifecycle, rationalisation and the measures, with a worksheet
Analogue indicatorData and software
An HMI element that shows a value as a pointer on a scale with its normal range shaded and the alarm limits marked, so an operator can see at a glance whether the value is normal.
Used in: High performance HMI: screens that show the operator what is abnormal, the display hierarchy, and the ISA-101 life cycle
Angle of reposeDEM and scanning
The angle a freely poured heap of bulk material forms with the horizontal. It is a quick bench indicator of flow behaviour and a common DEM calibration target.
Used in: Grain flow paths and chute upgrades guided by DEM
Apron feederProcess plants
A heavy-duty feeder built from overlapping steel pans, used to draw coarse, abrasive material out of a bin at a controlled rate.
Used in: Apron feeders: how they work, the capacity calculation, design points at the hopper and discharge, and the wear and maintenance of each part
ArchingBulk materials handling
A stable bridge of material forming across a hopper outlet and stopping flow. Outlet size and hopper wall angle are the usual design defences.
Used in: Grain flow paths and chute upgrades guided by DEM
Architecture decision record (ADR)Data and software
A short note recording one significant technical decision: the context, the options considered, the choice made and its consequences. Kept with the code, a set of them explains why a system is built the way it is.
Used in: Choosing a technology stack for industrial software
As-builtMaintenance and reliability
A drawing or document reissued after construction or modification to show what was actually built, from the field mark-ups made at commissioning, as distinct from the issued-for-construction revision that showed what was intended. The plant is operated and maintained from the as-built.
Used in: As-built drawings and redlines: from the mark-up in the field to the drawing the plant runs on, Single line diagrams explained: how to read one, what it has to carry, and the work that is done from it, Document control for plant: drawings, as-builts and the register that keeps them findable, Management of change for plant modifications: engineering change management, the test, the eight steps and the register
As-built modelDEM and scanning
A 3D model reflecting what is physically installed rather than what was originally designed. Scanning produces one, and it is the honest starting point for any modification.
Asset healthData and software
A combined judgement of an asset's condition, drawn from its condition monitoring, process data and failure history, often shown as a score or a state. It is the main output of asset performance management.
Used in: Asset performance management: what APM covers, the data it runs on, how it differs from a CMMS, and how to tell whether it is working
Asset integrity managementMaintenance and reliability
The systematic work of keeping the equipment that contains, controls or protects against a hazard fit for purpose across its life, with evidence. Usually described as design, technical and operating integrity, and built around safety critical elements and their performance standards.
Used in: Asset integrity management: what it covers, the standards behind it, and how it fits with maintenance
Asset life cycleMaintenance and reliability
The stages an asset passes through from the need for it to its disposal: need, design and acquisition, commissioning, operation and maintenance, and renewal or disposal. ISO 55000 defines it as the stages involved in the management of an asset. Most of the whole of life cost is committed by the end of design and spent during operation.
Used in: Obsolescence management: the stages, the ways out, what sets the risk and the register that holds it, Decommissioning and asset disposal: six stages from the decision to the closed records, Asset lifecycle management: the stages, the decisions at each, and the cost that follows them
Asset lifecycle management planMaintenance and reliability
A plan for a class of assets, or one significant asset, setting out the level of service it must deliver, the operating and maintenance approach through its life, the condition and performance it is judged on, the renewal forecast and its funding, and the information to be kept. It sits beneath the asset management plan and above the maintenance plans in the CMMS.
Used in: Asset lifecycle management: the stages, the decisions at each, and the cost that follows them
Asset performance management (APM)Data and software
Software that analyses condition, reliability and risk data to judge the health of assets and recommend action. It sits beside the CMMS or EAM, which holds the work, and usually raises work into it.
Used in: Asset performance management: what APM covers, the data it runs on, how it differs from a CMMS, and how to tell whether it is working, CMMS or EAM: the difference, and how to choose
Autonomous maintenanceMaintenance and reliability
The total productive maintenance practice of operators owning the basic care of the equipment they run: cleaning, lubricant levels, inspection against standards, tightening and adjustment needing no tool or isolation, and reporting. Built in steps from an initial clean to operators running and improving the inspection themselves. The Japanese term is jishu hozen.
Used in: Operator rounds and autonomous maintenance: the loop, the limits on the sheet, and the line between operators and maintenance

B

B10 lifeMaintenance and reliability
The age by which ten per cent of a population of items has failed, read off a fitted life distribution. Bearings are rated on it, and it is a common basis for a time-based replacement interval.
Used in: The bathtub curve is one of six: failure patterns, Weibull and the reliability block diagram
B2MMLData and software
Business to Manufacturing Markup Language, a set of XML and JSON schemas implementing the ISA-95 object models so systems can exchange schedules, performance, material and equipment information in a standard format.
Used in: ISA-95 explained: the levels, the equipment hierarchy, what passes between business and operations, and how it relates to the Purdue model
BackpressureData and software
A mechanism that slows producers when consumers cannot keep up, so a busy system degrades gracefully instead of exhausting memory and collapsing.
Used in: Building software that runs a 24/7 operation
Bathtub curveMaintenance and reliability
Failure rate against age drawn as high at first, flat in the middle and rising at the end: infant mortality, useful life and wear-out. A useful picture of a simple item with one ageing mechanism and a poor model for complex equipment. The airline studies that classified failure patterns found it fitted about four per cent of items.
Used in: The bathtub curve is one of six: failure patterns, Weibull and the reliability block diagram
Battery limitsMechanical and structural
The boundaries of a supplier's scope: where their supply ends and the owner's or another package begins, for each connection such as pipework, power, structure and control signals. Best drawn as well as written.
Used in: Tender documents and the tender process: what goes in a request for tender, what tenderers return, evaluation criteria, and what causes trouble later, Writing a technical specification: how open to make it, its sections, the parts of a good requirement, and the maintenance requirements usually missed
Belt spliceBulk materials handling
The joint that makes a conveyor belt endless, either vulcanised, where the layers are bonded under heat and pressure, or mechanical, with metal fasteners. A splice that is not square makes the belt shift sideways each time it passes.
Used in: Conveyor belt splicing: hot and cold vulcanised and mechanical splices, how a stepped splice is made, splice faults, and the register that finds them early, Conveyor belt tracking and maintenance: the tracking rule, finding the cause of mistracking, training a belt, and the inspections that keep conveyors running
Belt trackingBulk materials handling
Keeping a conveyor belt running centrally on its idlers. Poor tracking causes edge damage, spillage and structural wear, and often traces back to off-centre loading.
Used in: Conveyor belt splicing: hot and cold vulcanised and mechanical splices, how a stepped splice is made, splice faults, and the register that finds them early, Conveyor belt tracking and maintenance: the tracking rule, finding the cause of mistracking, training a belt, and the inspections that keep conveyors running
BeneficiationMining
The processing steps that raise the grade of run of mine material by separating valuable mineral from waste, typically through crushing, grinding, screening and concentration.
Best efficiency point (BEP)Process plants
The flow at which a centrifugal pump runs most efficiently for its speed and impeller. Running far from it causes recirculation, vibration and, in slurry pumps, faster local wear.
Used in: Centrifugal pumps and pump curves: the operating point, best efficiency point, affinity laws, cavitation and NPSH, and running in the wrong place, Slurry pumps: how they are built, what drives wear, liner materials, gland and mechanical seals, and planning wet end changes
Bucket wheel excavatorMining
A continuous digging machine with a rotating wheel of buckets, used in soft rock and overburden removal and on stockyards for reclaiming bulk material.
BucklingMechanical and structural
Sudden sideways failure of a slender member under compression, occurring well below the material's yield strength. Slenderness and restraint decide it.
Bulk materials handlingBulk materials handling
The engineering discipline concerned with moving, storing and controlling bulk solids such as ore, coal and grain, using conveyors, chutes, bins, feeders and stockyard machines.
Used in: Bulk materials handling: specifying a conveyor or chute so the design holds up, Grain flow paths and chute upgrades guided by DEM

C

Calibration (DEM)DEM and scanning
Tuning simulation parameters until the model reproduces measured bench behaviour such as angle of repose and shear response. Without it a DEM result is a plausible animation, not evidence.
Used in: What DEM modelling actually tells you about transfer chute design, Transfer chute redesign guided by DEM modelling
Care, custody and controlMaintenance and reliability
The responsibility for a plant or system, which passes from the construction contractor to the commissioning team and then to operations at handover. The party holding it controls access, isolation and operation, and the transfer is signed, not assumed.
Used in: Decommissioning and asset disposal: six stages from the decision to the closed records, Commissioning and the punch list: from mechanical completion to handover, with a template
Cartridge sealProcess plants
A mechanical seal supplied assembled and preset on its own sleeve with its gland plate, so it is fitted as one unit and the setting clips are removed before start up.
Used in: Mechanical seals: how they work, cartridge and dual seals, flush and barrier plans, how seals fail, and fitting them so they last
Cause and effect matrixData and software
A grid of every interlock and trip: the causes down the side with their tags, the effects along the top, and a mark where a cause produces an effect. One page a process engineer, a programmer and a tester can all read and check, and the master for interlock changes. On facilities with process safety obligations, also the record of the safety instrumented functions.
Used in: P&ID symbols and how to read a P&ID: lines, valves, instrument bubbles, tags and loops, Factory and site acceptance testing: what each proves, and how to write a test that tests the design, Control system design documents: the chain from the P&ID to the code, and the two the tests run from
CavitationMechanical and structural
Vapour bubbles forming in low pressure regions of a pump or valve and collapsing violently, pitting the metal and causing noise and vibration. In pumps it comes from too little NPSH available.
Used in: Centrifugal pumps and pump curves: the operating point, best efficiency point, affinity laws, cavitation and NPSH, and running in the wrong place
Centre of gravityMechanical and structural
The point a body's weight acts through. It governs lifting arrangements, transport stability and restraint design for oversize items.
Used in: Structural design and certification of transport frames
Chain pitchBulk materials handling
The distance between the centres of adjacent pins in a chain. Measured over a set number of links and trended, its growth shows wear in the pins and bushes and plans the change of chain and sprockets.
Used in: Apron feeders: how they work, the capacity calculation, design points at the hopper and discharge, and the wear and maintenance of each part
Chevron stackingMining
Building a stockpile by travelling the stacker back and forth along it, laying layers over the crest so the cross section looks like nested chevrons. Reclaimed across the full face, it blends grade and size.
Used in: Stacker reclaimers: the machine types, stacking methods and blending, the systems on each machine and how they fail, and structural integrity
Choke feedingMining
Keeping a cone crusher's chamber full of feed to a set level so the rock crushes against itself as well as the liners. It gives more even liner wear and a more consistent product than running the chamber partly empty.
Used in: Crusher maintenance and liners: wear parts by crusher type, the closed side setting, routine checks, and planning liner changes from measured wear
Clash detectionDEM and scanning
Checking a proposed design against the scanned as-built environment to find physical interferences before fabrication rather than during a shutdown.
Closed side setting (CSS)Mining
The smallest gap between the moving and fixed crushing surfaces during each cycle, at the bottom of the chamber of a cone, gyratory or jaw crusher. It largely sets the product size and opens as the liners wear.
Used in: Crusher maintenance and liners: wear parts by crusher type, the closed side setting, routine checks, and planning liner changes from measured wear
CMMS and EAMMaintenance and reliability
Computerised maintenance management and enterprise asset management systems: the software holding the asset register, work orders, history and materials. Common examples are SAP PM, Pronto Xi and IBM Maximo.
Used in: Maintenance backlog: counting it in crew-weeks by trade, ready and total backlog, reading the trend, and keeping it honest with a review, The equipment maintenance log: what an entry should hold, codes that can be counted, what the history is used for, and a free template, Asset performance management: what APM covers, the data it runs on, how it differs from a CMMS, and how to tell whether it is working, CMMS implementation and selection: seven phases, a scorecard, and the data build that decides the result, Preventive maintenance: building a program that earns its place, with a checklist template, What a work order is, and how work order management actually works, Shutdown planning: the checklist, the scope freeze and the schedule that holds, Maintenance planning and scheduling: the weekly cycle that keeps a plant running, ISO 55001 explained: what the asset management standard requires, and what changed in 2024, Asset integrity management: what it covers, the standards behind it, and how it fits with maintenance, Fixed plant maintenance on a mine site: strategies, shutdowns, systems and the work that keeps it running, The asset register: the engineering register, the fixed asset register, and how to reconcile them, CMMS or EAM: the difference, and how to choose, ISO 14224, and building an asset hierarchy that holds up, The maintenance job pack, and what has to be in it, The asset management plan, and the strategic asset management plan it comes from, FMECA: how to run a failure modes, effects and criticality analysis, Condition monitoring: techniques, intervals and building a program that works, Planner, scheduler, long term planner: three different jobs, Operational readiness for new assets: the checklist, the methods, the standards and the CMMS build, Predictive maintenance and condition monitoring, Rebuilding asset hierarchies and maintenance master data, Work management and scheduling uplift, Shutdown coordination platform, Operational readiness for a new plant asset
Coefficient of restitutionDEM and scanning
A measure of how much velocity a particle retains after a collision, from zero for perfectly inelastic to one for perfectly elastic. It governs bounce and spread in a DEM model.
Cohesion and adhesionDEM and scanning
Cohesion is the tendency of particles to stick to each other, adhesion the tendency to stick to a surface. Both rise with moisture and drive the build-up that blocks chutes.
Used in: Bulk materials handling: specifying a conveyor or chute so the design holds up
ComminutionMining
Size reduction of ore by crushing and grinding. It is usually the largest single consumer of energy on a processing plant, so small efficiency gains matter.
Used in: Crusher maintenance and liners: wear parts by crusher type, the closed side setting, routine checks, and planning liner changes from measured wear
Conditions of tenderMechanical and structural
The rules of a tender: closing time and place, how to submit, how questions are asked and answered, alternative tenders, the validity period and how tenders will be evaluated. Separate from the conditions of contract, which govern the work.
Used in: Tender documents and the tender process: what goes in a request for tender, what tenderers return, evaluation criteria, and what causes trouble later
Configuration and customisationData and software
Configuration is setting up a software product's own options, fields, screens, workflows, codes and reports, with the vendor's tools, and it survives an upgrade. Customisation is code the product does not contain, unsupported by the vendor, reworked and paid for at every upgrade. A good implementation is met by configuration wherever it can be, with customisation named and costed.
Used in: CMMS implementation and selection: seven phases, a scorecard, and the data build that decides the result
Conformed dimensionData and software
A shared reference table, such as site or asset, used identically across multiple fact tables so figures from different reports can be compared with confidence.
Used in: Automated operations reporting, SQL data platform and ETL optimisation
Contact modelDEM and scanning
The physics used in a DEM simulation to calculate forces when particles touch each other or a surface, ranging from simple elastic springs to formulations that add cohesion.
Corrective maintenanceMaintenance and reliability
Maintenance carried out after a fault is detected, to restore the function. Deferred corrective maintenance is a fault found and planned into the schedule because it can safely wait. Immediate corrective maintenance is the fault that cannot wait, which is the breakdown. Reactive maintenance is the common name for the immediate kind.
Used in: Types of maintenance compared: preventive, predictive, condition based, corrective and run to failure
Crew-weekMaintenance and reliability
The work one trade's crew can do in a week, used as the unit of maintenance backlog: estimated hours of open work divided by the crew's weekly hours. A backlog of four crew-weeks would take the crew four weeks to clear if no new work arrived.
Used in: Maintenance backlog: counting it in crew-weeks by trade, ready and total backlog, reading the trend, and keeping it honest with a review
CriticalityMaintenance and reliability
A ranking of assets by the consequence of their failure across safety, environment, production and cost. It decides where maintenance and monitoring effort is worth spending.
Used in: Maintenance backlog: counting it in crew-weeks by trade, ready and total backlog, reading the trend, and keeping it honest with a review, Asset performance management: what APM covers, the data it runs on, how it differs from a CMMS, and how to tell whether it is working, Obsolescence management: the stages, the ways out, what sets the risk and the register that holds it, What a reliability engineer does, and what the role is not, Critical spares: deciding what to stock, and what to accept the risk on, Preventive maintenance: building a program that earns its place, with a checklist template, Root cause analysis for equipment failures: finding the cause you can actually fix, What a work order is, and how work order management actually works, Asset lifecycle management: the stages, the decisions at each, and the cost that follows them, Maintenance KPIs: fourteen measures, defined once and read together, Shutdown planning: the checklist, the scope freeze and the schedule that holds, Maintenance planning and scheduling: the weekly cycle that keeps a plant running, ISO 55001 explained: what the asset management standard requires, and what changed in 2024, Asset integrity management: what it covers, the standards behind it, and how it fits with maintenance, Fixed plant maintenance on a mine site: strategies, shutdowns, systems and the work that keeps it running, The asset register: the engineering register, the fixed asset register, and how to reconcile them, ISO 14224, and building an asset hierarchy that holds up, The asset management plan, and the strategic asset management plan it comes from, FMECA: how to run a failure modes, effects and criticality analysis, Condition monitoring: techniques, intervals and building a program that works, Running an asset criticality assessment that holds up, Reliability centred maintenance, and when criticality-led beats it, Operational readiness for new assets: the checklist, the methods, the standards and the CMMS build, Condition monitoring people actually act on, Predictive maintenance and condition monitoring, Rebuilding asset hierarchies and maintenance master data, Reliability engineering and asset strategy program, Operational readiness for a new plant asset, Asset management planning and the system behind it
Crusher linerMining
A replaceable wear part that lines a crusher's crushing chamber, such as the mantle and concave of a cone or gyratory crusher, or the jaw dies of a jaw crusher. Its life is usually tracked in tonnes crushed.
Used in: Crusher maintenance and liners: wear parts by crusher type, the closed side setting, routine checks, and planning liner changes from measured wear
Cut size (d50)Process plants
The particle size with an even chance of reporting to a classifier's coarse or fine product, such as a hydrocyclone's underflow or overflow. Finer cut sizes come from smaller cyclones, higher pressure and lower feed density.
Used in: Hydrocyclones: how a cyclone classifies, what moves the cut size, spray and roping, and maintaining a cyclone cluster
Cut-off gradeMining
The lowest grade of material that is economic to process. Material below it is treated as waste, so the cut-off drives both mine planning and plant feed.

D

Data historianData and software
A database optimised for storing time-stamped process measurements at high rates over long periods. AVEVA PI System is the most common example in industrial plants.
Used in: Unified namespace explained: one structure every plant system publishes to, how the topic tree follows ISA-95, and when a UNS is worth building, MES explained: what a manufacturing execution system does, where it sits between the ERP and the control systems, and what it is called in mining and process plants, Asset performance management: what APM covers, the data it runs on, how it differs from a CMMS, and how to tell whether it is working, Alarm management: the lifecycle, rationalisation and the measures, with a worksheet, Downtime tracking: the time model, the codes and the log that make the hours add up, Plant protocols explained: Modbus, OPC UA, MQTT and Sparkplug B, and where each belongs, OT security for plant systems: zones, conduits and the controls that fit a plant, What a data historian is, how it differs from a database, and when you need one, Fixed plant maintenance on a mine site: strategies, shutdowns, systems and the work that keeps it running, Choosing a technology stack for industrial software, CMMS or EAM: the difference, and how to choose, Condition monitoring: techniques, intervals and building a program that works, Digital transformation on a working mine site, Building software that runs a 24/7 operation, Predictive maintenance and condition monitoring, Automated operations reporting, Real-time production analytics, Bridging OT and IT with custom software
Data warehouseData and software
A database structured for analysis and reporting rather than transaction processing, holding integrated, historical data from multiple source systems.
Used in: What a data historian is, how it differs from a database, and when you need one, Automated operations reporting, SQL data platform and ETL optimisation
DecommissioningMaintenance and reliability
The deliberate removal of an asset from service at the end of its life: the decision recorded, the plan, making safe with every energy source and process connection isolated and verified, removal, reinstatement, and closing every record that said the asset existed. Stopping an asset is not decommissioning it.
Used in: Decommissioning and asset disposal: six stages from the decision to the closed records
Defect eliminationMaintenance and reliability
The routine that uses failure data and root cause analysis to remove the causes of recurring failures, usually working from a bad actor list. Where RCA is a method for one event, defect elimination decides which events get it, tracks the actions and measures whether the failures stop.
Used in: Operator rounds and autonomous maintenance: the loop, the limits on the sheet, and the line between operators and maintenance, Root cause analysis for equipment failures: finding the cause you can actually fix
DEM (Discrete Element Method)DEM and scanning
A simulation technique that models bulk material as many individual particles and integrates the contact forces between them, used to predict how material will flow through equipment before it is built.
Used in: What DEM modelling actually tells you about transfer chute design, Transfer chute redesign guided by DEM modelling
Desiccant breatherMechanical and structural
A breather on a gearbox or reservoir that filters incoming air and dries it through a desiccant, keeping dust and moisture out of the oil as it heats and cools.
Used in: Industrial gearbox maintenance: lubrication, routine checks, oil analysis, gear and bearing failure modes, and mounting and alignment
Design lifeMechanical and structural
The period a structure or component is designed to perform its function under its expected loads, and the basis for fatigue and corrosion allowances.
Design reviewProcess plants
A structured review of a design by people outside the design team, held at set points such as the 30, 60 and 90 per cent model reviews, to find problems while they are still cheap to change.
Used in: Engineering study phases: scoping, prefeasibility, feasibility and FEED, the gates between them, and the design reviews that catch problems early
Digital twinData and software
A model of a physical asset kept current with operating data, used to test scenarios and predict behaviour. Its value depends entirely on how faithfully it is maintained.
Direct on line (DOL) starterMaintenance and reliability
A motor starter that connects a motor straight to the full supply voltage through a contactor, with an overload or motor protection relay. The simplest starter, giving full starting torque at a starting current of roughly six to eight times full load current.
Used in: Motor starters compared: direct on line, star delta, soft starters and variable speed drives, and the motor control centre they sit in
Display hierarchyData and software
The arrangement of HMI screens in levels, commonly four: an area overview, unit control, equipment detail and support screens, with navigation running down the levels in a few clicks.
Used in: High performance HMI: screens that show the operator what is abnormal, the display hierarchy, and the ISA-101 life cycle
Distributed control system (DCS)Data and software
A plant wide control system of controllers, operator stations and engineering tools sold and engineered as one system, sharing one database for tags, alarms and history, with redundancy built in. Used on large continuous and batch process plants.
Used in: PLC, DCS and SCADA compared: what each does, where control lives, and how to choose for a plant or a network of remote sites
DNP3Data and software
Distributed Network Protocol, a SCADA protocol for water, power and other networks of remote sites, built for slow and unreliable links with time stamped events and reporting by exception. Published as IEEE 1815.
Used in: PLC, DCS and SCADA compared: what each does, where control lives, and how to choose for a plant or a network of remote sites
Document automationData and software
Producing documents from structured data and a template, rather than writing or copying each one. The template holds the layout, fixed text, fields, repeating sections and conditions, and the data supplies the values for each document.
Used in: Document and report automation for engineering and maintenance: the documents that suit it, how templates work, the checks that make it safe, and where people stay in charge
Document registerMaintenance and reliability
The index of every controlled document on a plant: its number, revision, state, owner, where the master is held, where copies are posted, and the equipment tags it describes so it can be found from the asset. The register is what has to be right, whatever system holds the files.
Used in: As-built drawings and redlines: from the mark-up in the field to the drawing the plant runs on, Single line diagrams explained: how to read one, what it has to carry, and the work that is done from it, Document control for plant: drawings, as-builts and the register that keeps them findable
Downtime codeMaintenance and reliability
A fixed, short hierarchy of causes, usually category, cause group and cause, that every downtime event is classified by, chosen from lists rather than typed, so the hours can be added up by cause across shifts and months. A breakdown is coded to the equipment that failed.
Used in: Shift logs and shift handover: what to record, the structured handover, and getting the log to feed the systems that act on it, Downtime tracking: the time model, the codes and the log that make the hours add up
Drill and blastMining
Drilling a pattern of holes, charging them with explosive and firing to fragment rock. Fragmentation quality carries straight through to loading rates, crusher throughput and wear.

E

Edge gatewayData and software
A device or software service near the plant that reads PLCs and other devices over their own protocols and passes the data on, often by publishing it to an MQTT broker.
Used in: Unified namespace explained: one structure every plant system publishes to, how the topic tree follows ISA-95, and when a UNS is worth building
Energy isolationMaintenance and reliability
Separating equipment from every source of energy, electrical, mechanical, hydraulic, pneumatic, stored and process, securing the isolation points so they cannot be operated, releasing stored energy and proving the equipment dead before work starts.
Used in: Permit to work and isolation: the stages of a permit, isolating and proving dead, and the link to the work order
Equipment hierarchy (ISA-95)Data and software
The role based structure ISA-95 uses to name a plant: enterprise, site, area, work centre and work unit, with work centres and units named by the kind of production, such as process cells, production units, production lines and storage zones.
Used in: ISA-95 explained: the levels, the equipment hierarchy, what passes between business and operations, and how it relates to the Purdue model
Equipment maintenance logMaintenance and reliability
The record of all maintenance done on a piece of equipment over its life: date, work type, work order, what was found, what was done, codes, parts, labour, downtime and readings. On most sites it is the work order history in the CMMS.
Used in: The equipment maintenance log: what an entry should hold, codes that can be counted, what the history is used for, and a free template
Estimate classProcess plants
A classification of a cost estimate by the maturity of the project definition behind it. AACE 18R-97 sets five classes for the process industries, from class 5 at concept screening to class 1 near the end of design, each with a typical accuracy range.
Used in: Engineering study phases: scoping, prefeasibility, feasibility and FEED, the gates between them, and the design reviews that catch problems early
ETL and ELTData and software
Extract, transform, load. The process of collecting data from source systems, reshaping and validating it, and loading it somewhere it can be analysed. ELT does the transform after loading.
Used in: Automated operations reporting, SQL data platform and ETL optimisation
Expression of interest (EOI)Mechanical and structural
An invitation for suppliers to show their interest and capability before full tender documents are issued, used to shortlist the tenderers for a large or specialised package.
Used in: Tender documents and the tender process: what goes in a request for tender, what tenderers return, evaluation criteria, and what causes trouble later

F

Factor of safetyMechanical and structural
The margin between the load a component can carry and the load it is expected to see, covering variation in material, loading and analysis.
Used in: Structural design and certification of transport frames
Factory acceptance test (FAT)Maintenance and reliability
A test of a system, usually a control system, switchboard, drive or packaged unit, at the vendor's works before shipment, witnessed by the buyer, to prove the system as built and configured meets the specification. Inputs are simulated. It is the last point at which a fault is fixed at the vendor's bench rather than on site.
Used in: Writing a technical specification: how open to make it, its sections, the parts of a good requirement, and the maintenance requirements usually missed, Factory and site acceptance testing: what each proves, and how to write a test that tests the design, Control system design documents: the chain from the P&ID to the code, and the two the tests run from
Failure mechanismMaintenance and reliability
The physical, chemical or other process that led to a failure, such as wear, fatigue, corrosion, leakage or overheating. ISO 14224 gives a standard list, so failures can be grouped and counted across assets.
Used in: The equipment maintenance log: what an entry should hold, codes that can be counted, what the history is used for, and a free template
Failure patternsMaintenance and reliability
The six shapes of failure rate against age found in the 1978 United Airlines study by Nowlan and Heap: bathtub, wear-out, gradual increase, initial increase, random and infant mortality. Only the first three have a rising rate that an age-based replacement can address, and most complex items follow the last two.
Used in: Types of maintenance compared: preventive, predictive, condition based, corrective and run to failure, The bathtub curve is one of six: failure patterns, Weibull and the reliability block diagram
False brinellingMaintenance and reliability
Wear marks on a bearing at the spacing of the rolling elements, caused by small movements or vibration while the bearing is not rotating, such as a standby machine beside a running one or equipment vibrating in transport.
Used in: Bearing failure analysis: why bearings fail early, the six ISO 15243 failure modes, the common causes and their signs, and examining a failed bearing
Fault tree analysis (FTA)Maintenance and reliability
A top down method for analysing how one undesired event can happen. The event sits at the top of a tree and its causes are drawn below it, joined by OR gates (any one cause is enough) and AND gates (all are needed together), down to basic component failures. Set out in IEC 61025.
Used in: Fault tree analysis: building the tree from the top event, gates and minimal cut sets, and where it sits beside FMECA and RCA
FEA (Finite Element Analysis)Mechanical and structural
A numerical method that divides a structure into small elements to calculate stress, deflection and fatigue life, used to verify that a design is fit for purpose before it is built.
Used in: Structural design and certification of transport frames
Feasibility study (DFS)Mining
The study that develops the selected option in enough detail to decide whether to fund it, with a defined scope, an execution plan and an estimate typically of AACE class 3. Also called a definitive or bankable feasibility study.
Used in: Engineering study phases: scoping, prefeasibility, feasibility and FEED, the gates between them, and the design reviews that catch problems early
Fixed asset registerMaintenance and reliability
The finance system's record of capitalised property, plant and equipment: cost, dates, useful life, depreciation and book value for each asset. It stops at the unit that was capitalised, so one record often covers many engineering records.
Used in: The asset register: the engineering register, the fixed asset register, and how to reconcile them
Fixed plantMaintenance and reliability
The stationary processing and handling equipment on a mine or industrial site: crushers, screens, mills, conveyors, feeders, pumps, thickeners, stackers and reclaimers. Maintained in place and around planned shutdowns, as distinct from the mobile fleet.
Used in: Fixed plant maintenance on a mine site: strategies, shutdowns, systems and the work that keeps it running
FlocculantProcess plants
A long chain polymer added to a slurry to bind fine particles into larger flocs that settle quickly, used in thickeners and clarifiers. The dose is usually given in grams per tonne of solids.
Used in: Thickeners: how they work, the types and parts, rake torque and the variables to watch, common problems, and maintaining a thickener
Flow functionDEM and scanning
The relationship between the consolidating stress applied to a bulk solid and the strength it develops. It is derived from shear cell testing and underpins hopper outlet sizing.
Used in: Bulk materials handling: specifying a conveyor or chute so the design holds up
FlutingMaintenance and reliability
Evenly spaced grey lines across a bearing raceway, like a washboard, caused by electrical current passing through the bearing. Common in motors fed by variable speed drives without insulated bearings or shaft grounding.
Used in: Bearing failure analysis: why bearings fail early, the six ISO 15243 failure modes, the common causes and their signs, and examining a failed bearing
Front end engineering design (FEED)Process plants
The basic engineering on a project's selected option before the final investment decision: process flow diagrams, P&IDs issued for design, the equipment list, layouts, main specifications, an estimate and the execution plan. It ends with a scope freeze.
Used in: Engineering study phases: scoping, prefeasibility, feasibility and FEED, the gates between them, and the design reviews that catch problems early
Frozen scheduleMaintenance and reliability
The weekly maintenance schedule once it has been agreed and issued on a fixed day. Work added after that point is break-in work, which is what makes schedule compliance and break-in share measurable.
Used in: Maintenance KPIs: fourteen measures, defined once and read together, Maintenance planning and scheduling: the weekly cycle that keeps a plant running
Functional design specification (FDS)Data and software
The document that says in words what a control system does, loop by loop and sequence by sequence, in every mode and on every abnormal path. Also called the control narrative. The programmer codes from it, the factory acceptance test is written against it, and operations learn the plant from it. A thin one makes all three guess.
Used in: Control system design documents: the chain from the P&ID to the code, and the two the tests run from
Functional failureMaintenance and reliability
The inability of an item to deliver a function to the standard required, fully or partly. Several different failure modes can cause the same functional failure.
Used in: Root cause analysis for equipment failures: finding the cause you can actually fix, FMECA: how to run a failure modes, effects and criticality analysis
Functional locationMaintenance and reliability
A position in the plant where equipment is installed, as distinct from the equipment itself. Keeping the two separate lets history follow both the place and the machine.
Used in: SAP PM explained: functional locations and equipment, task lists and maintenance plans, the work order cycle and statuses, and the master data that makes it work, The equipment maintenance log: what an entry should hold, codes that can be counted, what the history is used for, and a free template, ISA-95 explained: the levels, the equipment hierarchy, what passes between business and operations, and how it relates to the Purdue model, Asset tagging and equipment numbering: what a tag identifies, site conventions and IEC 81346, and how to retag an operating plant, CMMS implementation and selection: seven phases, a scorecard, and the data build that decides the result, Document control for plant: drawings, as-builts and the register that keeps them findable, Downtime tracking: the time model, the codes and the log that make the hours add up, What a work order is, and how work order management actually works, What a data historian is, how it differs from a database, and when you need one, The asset register: the engineering register, the fixed asset register, and how to reconcile them, CMMS or EAM: the difference, and how to choose, ISO 14224, and building an asset hierarchy that holds up, The maintenance job pack, and what has to be in it, The asset management plan, and the strategic asset management plan it comes from, Operational readiness for new assets: the checklist, the methods, the standards and the CMMS build, Master data is boring, until your schedule falls apart, Rebuilding asset hierarchies and maintenance master data, Operational readiness for a new plant asset
Funnel flowBulk materials handling
A discharge pattern where only a central channel of material moves while the rest remains stationary. It causes segregation, first in last out behaviour and ratholing.
Used in: Grain flow paths and chute upgrades guided by DEM

G

Gland packingProcess plants
Rings of braided packing compressed around a pump shaft to seal it, with clean flush water fed in at a pressure above the pump so slurry is kept out of the packing.
Used in: Mechanical seals: how they work, cartridge and dual seals, flush and barrier plans, how seals fail, and fitting them so they last, Slurry pumps: how they are built, what drives wear, liner materials, gland and mechanical seals, and planning wet end changes
GradeMining
The concentration of the valuable component in ore, usually expressed as a percentage or grams per tonne.

H

Haul roadMining
The engineered road network trucks run on. Geometry, surface condition and drainage drive cycle times, fuel burn and tyre life.
Hazard rateMaintenance and reliability
The instantaneous failure rate of the items still surviving at a given age. Whether it falls, stays flat or rises with age is what decides between a time-based task, a condition task and leaving an item to run.
Used in: The bathtub curve is one of six: failure patterns, Weibull and the reliability block diagram
High performance HMIData and software
A way of designing control system screens so operators see abnormal conditions early: a muted grey background, colour reserved for abnormal states and alarms, analogue indicators against the normal range, embedded trends and a display hierarchy built around the operator's tasks.
Used in: High performance HMI: screens that show the operator what is abnormal, the display hierarchy, and the ISA-101 life cycle
Hood and spoon chuteBulk materials handling
A curved transfer chute design where a hood gathers the discharge stream and a spoon redirects it onto the receiving belt, keeping the stream coherent and reducing impact.
Used in: Chute liners: how transfer chutes wear, liner materials and where each belongs, laying out liners, and planning changes from measured wear, What DEM modelling actually tells you about transfer chute design
Hopper half angleBulk materials handling
The angle of a hopper wall measured from vertical. Together with wall friction it decides whether the hopper achieves mass flow or funnel flow.
Human machine interface (HMI)Data and software
The screens and controls through which an operator monitors and runs a process, on a local panel or a control room workstation.
Used in: High performance HMI: screens that show the operator what is abnormal, the display hierarchy, and the ISA-101 life cycle
HydrocycloneProcess plants
A static separator that uses centrifugal force in a conical vessel to split a slurry by particle size, commonly used to close a grinding circuit.
Used in: Hydrocyclones: how a cyclone classifies, what moves the cut size, spray and roping, and maintaining a cyclone cluster

I

IdempotencyData and software
The property that performing an operation twice has the same effect as performing it once. It is what makes retrying a failed load safe rather than double-counting.
Used in: Building software that runs a 24/7 operation, SQL data platform and ETL optimisation, Bridging OT and IT with custom software
IEC 61131-3Data and software
The international standard for PLC programming languages: ladder diagram, function block diagram and structured text, with sequential function charts for program structure. The 2025 edition is the fourth.
Used in: PLC, DCS and SCADA compared: what each does, where control lives, and how to choose for a plant or a network of remote sites
IEC 62443Data and software
The series of standards for the security of industrial automation and control systems, developed by ISA and published by the IEC. Its parts cover the owner's security program, the zones and conduits risk assessment, the system requirements at four security levels, and the requirements on component vendors.
Used in: PLC, DCS and SCADA compared: what each does, where control lives, and how to choose for a plant or a network of remote sites, OT security for plant systems: zones, conduits and the controls that fit a plant
IEC 81346Maintenance and reliability
The international standard series for structuring principles and reference designations of industrial systems, installations and equipment. Part 1 sets the rules for building reference designations and Part 2 the classes and letter codes for objects.
Used in: Asset tagging and equipment numbering: what a tag identifies, site conventions and IEC 81346, and how to retag an operating plant
Impact plateBulk materials handling
A sacrificial wear surface positioned where the material stream strikes the chute, taking the impact energy in place of the chute structure.
Used in: Chute liners: how transfer chutes wear, liner materials and where each belongs, laying out liners, and planning changes from measured wear
Infrared thermographyMaintenance and reliability
Imaging surface temperature with an infrared camera to find abnormal heat, such as loose electrical connections, failing bearings or damaged refractory. Readings need correcting for the surface's emissivity and for reflected heat.
Used in: Electrical preventive maintenance: the program along the power path, from the supply to the motors, Condition monitoring: techniques, intervals and building a program that works
Instrument tagProcess plants
The identification of an instrument on a P&ID and on the plant: letters for the measured variable and the functions, such as PT for a pressure transmitter or TIC for a temperature indicating controller, and a loop number shared by every instrument in the loop. Set out in ANSI/ISA-5.1.
Used in: Loop diagrams: what an instrument loop diagram shows, how to read one, loop types, scaling 4 to 20 mA, and keeping loop drawings current, Asset tagging and equipment numbering: what a tag identifies, site conventions and IEC 81346, and how to retag an operating plant, P&ID symbols and how to read a P&ID: lines, valves, instrument bubbles, tags and loops
Interface control document (ICD)Data and software
The written agreement for one interface between two systems: the data that crosses with its meaning and units, which system is master of each field, the direction, trigger, protocol, timing, error handling and the tests that prove it works.
Used in: System integration for plant systems: the interfaces between the plant and the business, the three patterns, and how an integration project is run
IO listData and software
The list of every input and output a control system has: tag, description, type, signal, range and units, the controller address it lands on, the cable and junction box, the alarms and interlocks it takes part in, and the loop drawing. The panel is designed from it, the loop diagrams are drawn from it, and the IO check and the loop check walk it line by line.
Used in: Loop diagrams: what an instrument loop diagram shows, how to read one, loop types, scaling 4 to 20 mA, and keeping loop drawings current, P&ID symbols and how to read a P&ID: lines, valves, instrument bubbles, tags and loops, Control system design documents: the chain from the P&ID to the code, and the two the tests run from
ISA-101Data and software
ANSI/ISA-101.01, the ISA standard for human machine interfaces in process automation, covering the HMI life cycle from philosophy and style guide to design, operation and maintenance. IEC 63303:2024 is the international standard derived from it.
Used in: High performance HMI: screens that show the operator what is abnormal, the display hierarchy, and the ISA-101 life cycle
IT OT integrationData and software
Connecting the operational technology that runs the plant, such as PLCs, SCADA and historians, with the information technology that runs the business. Also called IT OT convergence. Usually designed around a DMZ, with data flowing up and out, and secured to IEC 62443.
Used in: System integration for plant systems: the interfaces between the plant and the business, the three patterns, and how an integration project is run

J

Jenike shear cellDEM and scanning
The standard bench apparatus for measuring the cohesive strength, internal friction and wall friction of a bulk solid, described in ASTM D6128 and the basis of flow property design.
Used in: Bulk materials handling: specifying a conveyor or chute so the design holds up, Transfer chute redesign guided by DEM modelling
Junction boxMaintenance and reliability
An enclosure in the field where the cables from individual instruments are terminated and joined to a multicore cable running back to the control room or cabinet.
Used in: Loop diagrams: what an instrument loop diagram shows, how to read one, loop types, scaling 4 to 20 mA, and keeping loop drawings current

K

KittingMaintenance and reliability
Picking the parts and materials for a scheduled maintenance job ahead of time and staging them together, labelled with the work order, so the crew can start without going to the store.
Used in: Wrench time: what counts, measuring it with a work sampling study, where the shift goes, and how planning and kitting raise it, Spare parts and MRO inventory management: classes of stock, min and max levels, the catalogue, kitting, and slow moving stock

L

Last time buyMaintenance and reliability
An order placed before a supplier ends production of an item, for enough to last to the planned replacement plus a margin for the failure rate. Suppliers announce a last time buy date, after which the item cannot be bought new. The cheapest resolution to obsolescence when the forecast is right, and the dearest when it is wrong.
Used in: Obsolescence management: the stages, the ways out, what sets the risk and the register that holds it
Legacy systemData and software
A software system still in use whose platform, code or knowledge base makes it hard to change, support or secure. Old is not the same as legacy: a system becomes legacy when keeping it running carries a cost or risk the business has to manage.
Used in: Legacy system modernisation: finding out what you have, the options from retain to replace, and moving off it one function at a time
Level of serviceMaintenance and reliability
What an asset or service must deliver to those who use it, with a measure and a target, such as availability, throughput at specification or response time. Costing a level of service is what lets budget be traded against consequence.
Used in: Asset lifecycle management: the stages, the decisions at each, and the cost that follows them, ISO 55001 explained: what the asset management standard requires, and what changed in 2024, The asset management plan, and the strategic asset management plan it comes from, Asset management planning and the system behind it
Life cycle costMaintenance and reliability
The whole of life cost of an asset worked out as a cash flow over time, usually discounted to a present value so options with different timing can be compared. ISO 15663 and ISO 15686-5 set out methods.
Used in: Critical spares: deciding what to stock, and what to accept the risk on, Asset lifecycle management: the stages, the decisions at each, and the cost that follows them
LineageData and software
The traceable path from a number on a report back to the source records that produced it. It is what makes a figure defensible under audit.
Used in: Rebuilding asset hierarchies and maintenance master data, Automated operations reporting, SQL data platform and ETL optimisation
Live capacityProcess plants
The portion of a bin or stockpile that will actually flow out under gravity, as opposed to the total volume. Dead capacity is the remainder that stagnates.
Load and haulMining
The excavation and transport cycle, typically excavators or loaders feeding haul trucks. Cycle time is the core productivity measure.
Load caseMechanical and structural
A defined combination of loads a design must withstand, such as operating, transport, lifting or wind. Structures are checked against every credible combination.
Used in: Structural design and certification of transport frames
Lockout tagout (LOTO)Maintenance and reliability
Placing a personal lock on each isolation point, or on a lock box holding the isolation keys, with a tag saying who placed it and why. Each person working applies their own lock and removes it only when they have finished.
Used in: Permit to work and isolation: the stages of a permit, isolating and proving dead, and the link to the work order
Loop checkMaintenance and reliability
The end-to-end test of one signal from the field device to the control system and back: the switch operated or the transmitter driven, the input seen at the right address, in the right range and units, on the right display. Done at the site acceptance test for every row of the IO list, and recorded on a loop check sheet.
Used in: Loop diagrams: what an instrument loop diagram shows, how to read one, loop types, scaling 4 to 20 mA, and keeping loop drawings current, Factory and site acceptance testing: what each proves, and how to write a test that tests the design, Control system design documents: the chain from the P&ID to the code, and the two the tests run from
Loop diagramMaintenance and reliability
An instrumentation drawing showing one loop from the field device to the control system channel, with every terminal, cable, core, barrier, power source, shield earth and the calibrated range. ISA-5.4 describes its content.
Used in: Loop diagrams: what an instrument loop diagram shows, how to read one, loop types, scaling 4 to 20 mA, and keeping loop drawings current

M

Maintainability reviewProcess plants
A design review in which operators and maintainers walk the model and check how each piece of equipment will be inspected, isolated, lifted, removed and replaced, and that the spares and condition monitoring access are designed in.
Used in: Engineering study phases: scoping, prefeasibility, feasibility and FEED, the gates between them, and the design reviews that catch problems early
Maintenance managerMaintenance and reliability
The role accountable for the maintenance function on a site or a large part of one: the budget, the maintenance strategy and asset management plan, the organisation and its competence, the large contracts, and reporting availability, cost and safety.
Used in: Maintenance manager, superintendent and supervisor: what each role does, who decides what, and the rhythm each one runs on
Maintenance planMaintenance and reliability
In SAP PM and similar systems, the object that calls a task list on a schedule, by time, counter reading or a strategy of packages, and generates preventive orders ahead of their due date.
Used in: SAP PM explained: functional locations and equipment, task lists and maintenance plans, the work order cycle and statuses, and the master data that makes it work
Maintenance superintendentMaintenance and reliability
A role common on Australian mine and processing sites between the supervisors and the maintenance manager, responsible for an area with several crews, its contractors and budget, and the weekly schedule agreed with operations.
Used in: Maintenance manager, superintendent and supervisor: what each role does, who decides what, and the rhythm each one runs on
Maintenance supervisorMaintenance and reliability
The role that leads a maintenance crew through a shift or roster: allocating the day's work from the schedule, making sure it is done safely, responding to breakdowns, and checking that work orders are closed out properly.
Used in: Maintenance manager, superintendent and supervisor: what each role does, who decides what, and the rhythm each one runs on
Manufacturing operations management (MOM)Data and software
Level 3 of ISA-95: the activities that run production shift by shift across four areas, production, maintenance, quality and inventory, between business planning above and process control below.
Used in: ISA-95 explained: the levels, the equipment hierarchy, what passes between business and operations, and how it relates to the Purdue model
Mass balanceProcess plants
An accounting of material in and out of a process, used to check that measurements are consistent and to find where instruments or assumptions are wrong.
Used in: Real-time production analytics
Mass flowBulk materials handling
A discharge pattern where all the material in a bin is in motion whenever any is drawn off. It gives first in first out behaviour and avoids stagnant zones.
Used in: Transfer chute redesign guided by DEM modelling, Grain flow paths and chute upgrades guided by DEM
Master alarm databaseData and software
The one record of every alarm on a plant and its rationalised cause, consequence, action, priority, setpoint and deadband. The control system is configured from it, and any change to an alarm goes through it, so that it stays the truth about what every alarm is for.
Used in: Alarm management: the lifecycle, rationalisation and the measures, with a worksheet
Master dataMaintenance and reliability
The reference data describing assets, materials, locations and cost objects. Every work order and cost attaches to it, so errors compound rather than cancel out.
Used in: Document and report automation for engineering and maintenance: the documents that suit it, how templates work, the checks that make it safe, and where people stay in charge, Asset tagging and equipment numbering: what a tag identifies, site conventions and IEC 81346, and how to retag an operating plant, Legacy system modernisation: finding out what you have, the options from retain to replace, and moving off it one function at a time, CMMS implementation and selection: seven phases, a scorecard, and the data build that decides the result, Document control for plant: drawings, as-builts and the register that keeps them findable, Critical spares: deciding what to stock, and what to accept the risk on, What a work order is, and how work order management actually works, Maintenance planning and scheduling: the weekly cycle that keeps a plant running, ISO 55001 explained: what the asset management standard requires, and what changed in 2024, The asset register: the engineering register, the fixed asset register, and how to reconcile them, CMMS or EAM: the difference, and how to choose, ISO 14224, and building an asset hierarchy that holds up, The maintenance job pack, and what has to be in it, The asset management plan, and the strategic asset management plan it comes from, Operational readiness for new assets: the checklist, the methods, the standards and the CMMS build, Master data is boring, until your schedule falls apart, Rebuilding asset hierarchies and maintenance master data, Operational readiness for a new plant asset, Asset management planning and the system behind it
Mechanical completionMaintenance and reliability
The project milestone at which construction of a system is finished and its pre-commissioning checks are done, so it can pass from construction to commissioning. It is usually certified system by system rather than for a whole plant.
Used in: Commissioning and the punch list: from mechanical completion to handover, with a template, Operational readiness for new assets: the checklist, the methods, the standards and the CMMS build
Mechanical sealProcess plants
A shaft seal in which a rotating face fixed to the shaft runs against a stationary face, held together by springs or bellows on a thin liquid film. It leaks far less than gland packing and needs no adjustment.
Used in: Mechanical seals: how they work, cartridge and dual seals, flush and barrier plans, how seals fail, and fitting them so they last
MESData and software
Manufacturing execution system. Level 3 software that manages and records production as it happens: what was made or processed, on which equipment and to what specification. In mining and processing it often sits beside the historian and the laboratory system.
Used in: ISA-95 explained: the levels, the equipment hierarchy, what passes between business and operations, and how it relates to the Purdue model, MES explained: what a manufacturing execution system does, where it sits between the ERP and the control systems, and what it is called in mining and process plants, Choosing a technology stack for industrial software
Metallurgical accountingProcess plants
The formal reconciliation of tonnes and grade through the plant, producing the recovery and production figures the business reports on.
Used in: MES explained: what a manufacturing execution system does, where it sits between the ERP and the control systems, and what it is called in mining and process plants
MicropittingMechanical and structural
Fine surface fatigue on gear teeth that appears as grey, frosted bands, caused by thin oil films under heavy load. It can grow into macropitting and loss of tooth profile.
Used in: Industrial gearbox maintenance: lubrication, routine checks, oil analysis, gear and bearing failure modes, and mounting and alignment
MiddlewareData and software
An integration layer that every system connects to once, which maps, routes and monitors the data passing between them. It replaces a web of point to point interfaces with one link per system.
Used in: System integration for plant systems: the interfaces between the plant and the business, the three patterns, and how an integration project is run
Minimal cut setMaintenance and reliability
The smallest combination of basic events in a fault tree that together cause the top event, so that removing any one of them would stop it. A cut set of one event is a single point of failure.
Used in: Fault tree analysis: building the tree from the top event, gates and minimal cut sets, and where it sits beside FMECA and RCA
ModbusData and software
A simple polling protocol from 1979 in which a client reads numbered registers and coils from a device, over serial (RTU) or Ethernet (TCP, port 502). Spoken by most drives, meters and small controllers. The registers carry no names, types or units, and the protocol has no security, so the register map and the network around it do the work.
Used in: Plant protocols explained: Modbus, OPC UA, MQTT and Sparkplug B, and where each belongs
MothballingMaintenance and reliability
Taking an asset out of service with the intent of returning it: isolated and made safe, preserved rather than removed, inspected on a reduced maintenance plan that stays live, and kept on the register and the insurance schedule with a return trigger written down. Leaving an asset in place with none of that is abandonment.
Used in: Decommissioning and asset disposal: six stages from the decision to the closed records
Motor control centre (MCC)Maintenance and reliability
A switchboard assembly that groups the starters for many motors, with an incoming section, busbars and one functional unit per motor holding its isolator, protection, starter and control. Built and verified to IEC 61439.
Used in: Motor starters compared: direct on line, star delta, soft starters and variable speed drives, and the motor control centre they sit in
MRO inventoryMaintenance and reliability
The maintenance, repair and operations stock a site holds to keep its plant running: spare parts, consumables, lubricants, tools, rotables and insurance spares, as distinct from raw materials and product.
Used in: Spare parts and MRO inventory management: classes of stock, min and max levels, the catalogue, kitting, and slow moving stock

N

Net present value (NPV)Maintenance and reliability
The value today of a series of future cash flows, each reduced by a discount rate for the years until it occurs. Comparing options on NPV puts money spent now and money spent later on the same footing.
Used in: Asset lifecycle management: the stages, the decisions at each, and the cost that follows them
Non-destructive testing (NDT)Mechanical and structural
Inspection techniques such as ultrasonic, magnetic particle and dye penetrant that find flaws in welds and materials without damaging the component.
NPSHMechanical and structural
Net positive suction head: the margin of suction pressure above the liquid's vapour pressure at the pump inlet. The NPSH available from the system must exceed the NPSH the pump requires, or the pump cavitates.
Used in: Centrifugal pumps and pump curves: the operating point, best efficiency point, affinity laws, cavitation and NPSH, and running in the wrong place
Nut factorMechanical and structural
The factor K in the bolt torque relation T = K × F × d, which lumps together thread and nut face friction. Commonly about 0.2 for plain dry steel bolts and lower when lubricated.
Used in: Bolt torque and bolted joints: preload, where the torque goes, an indicative torque table, tightening methods, and why joints come loose

O

Obsolescence managementMaintenance and reliability
Knowing which items a plant depends on are at risk of no longer being obtainable or supported, deciding in advance what will be done about each, and doing it before the failure that makes the decision urgent. IEC 62402 sets out the requirements. On a plant it is a register of items at risk with their supplier status, years of cover, resolution and owner.
Used in: Obsolescence management: the stages, the ways out, what sets the risk and the register that holds it
OEEMaintenance and reliability
Overall equipment effectiveness, the product of availability, performance and quality. It exposes which of the three is actually constraining output.
Used in: Downtime tracking: the time model, the codes and the log that make the hours add up, Maintenance KPIs: fourteen measures, defined once and read together, Real-time production analytics
Operational readinessMaintenance and reliability
Everything that has to be in place for a new or modified asset to be operated safely and maintained properly from handover: people, procedures, approvals, spares, data, strategies and systems. Maintenance readiness is the part concerned with keeping the asset running.
Used in: Commissioning and the punch list: from mechanical completion to handover, with a template, Asset lifecycle management: the stages, the decisions at each, and the cost that follows them, Asset integrity management: what it covers, the standards behind it, and how it fits with maintenance, Operational readiness for new assets: the checklist, the methods, the standards and the CMMS build
Operator roundMaintenance and reliability
A fixed route of inspection points walked by an operator at a set frequency, usually each shift, with a specific check at each point, what normal looks like and the limit at which the operator acts, on the sheet. The readings are recorded and trended. It is the first line of condition monitoring, by the people who are there every shift.
Used in: Crusher maintenance and liners: wear parts by crusher type, the closed side setting, routine checks, and planning liner changes from measured wear, Shift logs and shift handover: what to record, the structured handover, and getting the log to feed the systems that act on it, Operator rounds and autonomous maintenance: the loop, the limits on the sheet, and the line between operators and maintenance
OverburdenMining
Waste material sitting above the ore body that has to be removed to expose it. The ratio of waste to ore is the strip ratio.

P

Parallel runData and software
Running an old and a new system side by side on the same inputs for a set period and comparing their outputs, to prove the new system does what the old one did before the old one is switched off.
Used in: Legacy system modernisation: finding out what you have, the options from retain to replace, and moving off it one function at a time
Particle scalingDEM and scanning
Representing real fine particles with fewer, larger simulated ones to keep a DEM model computable. It is a legitimate technique that has to be justified rather than hidden.
PartitioningData and software
Splitting a large database table into smaller physical pieces, commonly by date, so queries scan only the relevant portion and maintenance is faster.
Performance specificationMechanical and structural
A specification that states what an item must achieve, measurably and under stated conditions, and leaves the supplier to decide how. Design risk stays with the supplier, unlike a prescriptive specification that says how it is built.
Used in: Writing a technical specification: how open to make it, its sections, the parts of a good requirement, and the maintenance requirements usually missed
Permit to workMaintenance and reliability
A formal written system for controlling hazardous or non-routine work. It sets out the work, its location, the hazards, the precautions and isolations required, who may do it and for how long, and it is issued, accepted, handed over and closed by named authorities.
Used in: Wrench time: what counts, measuring it with a work sampling study, where the shift goes, and how planning and kitting raise it, Shift logs and shift handover: what to record, the structured handover, and getting the log to feed the systems that act on it, Permit to work and isolation: the stages of a permit, isolating and proving dead, and the link to the work order
Planned maintenance percentageMaintenance and reliability
The share of maintenance labour hours spent on planned work rather than reactive work. It is one of the clearest indicators of maintenance maturity.
Used in: Maintenance KPIs: fourteen measures, defined once and read together, Maintenance planning and scheduling: the weekly cycle that keeps a plant running, The maintenance job pack, and what has to be in it, Work management and scheduling uplift
PM complianceMaintenance and reliability
The share of preventive work orders completed inside their due window, over all that fell due in the period. A leading measure, read beside the corrective backlog: a program that is done but addresses the wrong failures shows high compliance and a growing backlog.
Used in: Preventive maintenance: building a program that earns its place, with a checklist template
Point cloudDEM and scanning
The raw output of a 3D scan: millions of measured points in space, later cleaned, registered and converted into surfaces or a model.
Pre-startup safety review (PSSR)Maintenance and reliability
A formal check before hazardous materials or energy are first introduced that an asset matches its design, procedures are in place, hazard review actions are resolved and people are trained. A required element of process safety management in some jurisdictions.
Used in: Management of change for plant modifications: engineering change management, the test, the eight steps and the register, Commissioning and the punch list: from mechanical completion to handover, with a template, Operational readiness for new assets: the checklist, the methods, the standards and the CMMS build
Prefeasibility study (PFS)Mining
The study phase that compares the options for a project on one basis and selects one to take forward, with an estimate typically of AACE class 4. Under the JORC Code, ore reserves need at least a prefeasibility study behind them.
Used in: Engineering study phases: scoping, prefeasibility, feasibility and FEED, the gates between them, and the design reviews that catch problems early
PreloadMechanical and structural
The tension in a bolt after tightening, which clamps the joint together. Correct preload keeps the joint from slipping and protects the bolt from fatigue.
Used in: Vibrating screens and screen panels: screen types, the parts, panel materials, blinding and cracking, and the maintenance that keeps sizing right, Bolt torque and bolted joints: preload, where the torque goes, an indicative torque table, tightening methods, and why joints come loose
Preventive maintenanceMaintenance and reliability
Work done at a planned interval, in time, usage or condition, to stop a failure occurring or to find one before it has a consequence. It covers fixed interval service and replacement, inspection, condition monitoring tasks and failure-finding tests. Spelt preventative in everyday Australian usage; the standards use preventive.
Used in: Types of maintenance compared: preventive, predictive, condition based, corrective and run to failure, Single line diagrams explained: how to read one, what it has to carry, and the work that is done from it, Operator rounds and autonomous maintenance: the loop, the limits on the sheet, and the line between operators and maintenance, Electrical preventive maintenance: the program along the power path, from the supply to the motors, Preventive maintenance: building a program that earns its place, with a checklist template
Process flow diagram (PFD)Process plants
A simplified schematic of the major equipment and process streams, showing how material moves through the plant without the instrumentation detail of a P&ID.
Used in: P&ID symbols and how to read a P&ID: lines, valves, instrument bubbles, tags and loops
Production dispatchingData and software
Releasing scheduled orders or targets to the plant floor in sequence and tracking each as it starts, runs and finishes. A core MES function between the schedule and the control systems.
Used in: MES explained: what a manufacturing execution system does, where it sits between the ERP and the control systems, and what it is called in mining and process plants
Production environmentData and software
The live system that real users and real data depend on, as distinct from development and test copies. Production ready means fit to run there, with access control, backups, monitoring and a way to recover.
Used in: Taking a vibe-coded prototype to production
Programmable logic controller (PLC)Data and software
A rugged industrial computer that reads inputs, runs control logic and drives outputs for a machine or process cell, scanning its program every few milliseconds. Programmed in IEC 61131-3 languages such as ladder, function block and structured text.
Used in: PLC, DCS and SCADA compared: what each does, where control lives, and how to choose for a plant or a network of remote sites
Publish and subscribeData and software
An integration pattern in which systems publish data to named topics on a broker and any system that needs the data subscribes to it, without the publisher knowing who reads it. MQTT works this way.
Used in: Unified namespace explained: one structure every plant system publishes to, how the topic tree follows ISA-95, and when a UNS is worth building, System integration for plant systems: the interfaces between the plant and the business, the three patterns, and how an integration project is run
Pulley laggingBulk materials handling
A rubber or ceramic covering bonded to a conveyor pulley face to increase grip on the belt and protect the shell. Worn or detached lagging causes slip and mistracking.
Used in: Conveyor pulleys and lagging: the pulley positions, how a drive pulley grips the belt, choosing lagging, how pulleys fail and what to inspect, Conveyor belt tracking and maintenance: the tracking rule, finding the cause of mistracking, training a belt, and the inspections that keep conveyors running
Pump curveMechanical and structural
The head a centrifugal pump develops at each flow for a given impeller and speed, usually shown with efficiency, power and NPSH required. The pump runs where its curve meets the system curve.
Used in: Centrifugal pumps and pump curves: the operating point, best efficiency point, affinity laws, cavitation and NPSH, and running in the wrong place
Punch listMaintenance and reliability
The register of incomplete or defective items found during construction and commissioning, categorised by whether each must be closed before the next milestone or can be carried past it with an owner and a date.
Used in: Factory and site acceptance testing: what each proves, and how to write a test that tests the design, Commissioning and the punch list: from mechanical completion to handover, with a template, Shutdown planning: the checklist, the scope freeze and the schedule that holds, Operational readiness for new assets: the checklist, the methods, the standards and the CMMS build

R

Rake torqueProcess plants
The torque a thickener drive needs to turn the rake through the bed. Its trend is the early warning of a bed that is too deep, too dense or sanded, before the drive trips.
Used in: Thickeners: how they work, the types and parts, rake torque and the variables to watch, common problems, and maintaining a thickener
RatholingBulk materials handling
A vertical channel that empties through stationary material in a bin, leaving the surrounding volume stuck in place and cutting live capacity dramatically.
Used in: Grain flow paths and chute upgrades guided by DEM
Rating life (L10)Maintenance and reliability
The life in revolutions or hours that 90 per cent of a large group of identical bearings will reach or exceed under stated load and speed, calculated to ISO 281. Most bearings in service are removed before it for reasons other than fatigue.
Used in: Bearing failure analysis: why bearings fail early, the six ISO 15243 failure modes, the common causes and their signs, and examining a failed bearing
RDS-PP and KKSMaintenance and reliability
Two tag schemes for power plants published by VGB. KKS is the older scheme found on many operating stations. RDS-PP is its successor, an application of IEC 81346 for power plants including wind farms.
Used in: Asset tagging and equipment numbering: what a tag identifies, site conventions and IEC 81346, and how to retag an operating plant
ReclaimerMining
A stockyard machine that recovers material from a stockpile and feeds it to a conveyor, often paired with a stacker on the same rail.
Used in: Stacker reclaimers: the machine types, stacking methods and blending, the systems on each machine and how they fail, and structural integrity
RecoveryProcess plants
The proportion of valuable mineral in the feed that reports to the final product, expressed as a percentage. Small recovery gains are usually worth large sums.
RedlineMaintenance and reliability
A print of the current issued drawing marked up by hand, conventionally in red, to show where what was built differs from it: each change clouded, with what was done, the punch item or change that authorised it, who marked it and when. The raw material the as-built is drafted from, and not a document the plant runs on.
Used in: Loop diagrams: what an instrument loop diagram shows, how to read one, loop types, scaling 4 to 20 mA, and keeping loop drawings current, P&ID symbols and how to read a P&ID: lines, valves, instrument bubbles, tags and loops, As-built drawings and redlines: from the mark-up in the field to the drawing the plant runs on, Single line diagrams explained: how to read one, what it has to carry, and the work that is done from it
Reference designationMaintenance and reliability
An identifier for an object built under IEC 81346 from one or more aspects, each a tree of codes with its own prefix: an equals sign for the function aspect, a hyphen for the product aspect and a plus sign for the location aspect.
Used in: Asset tagging and equipment numbering: what a tag identifies, site conventions and IEC 81346, and how to retag an operating plant
RegistrationDEM and scanning
Aligning multiple scans taken from different positions into one coordinate system, so the combined point cloud is dimensionally consistent.
Reliability block diagramMaintenance and reliability
A drawing of a system as blocks for its items, in series where every item must work and in parallel where any one is enough, from which the system's reliability or availability is calculated. Series multiplies the probabilities; parallel redundancy raises them. IEC 61078 is the standard for the method.
Used in: Fault tree analysis: building the tree from the top event, gates and minimal cut sets, and where it sits beside FMECA and RCA, The bathtub curve is one of six: failure patterns, Weibull and the reliability block diagram
Reliability engineeringMaintenance and reliability
The discipline of analysing failure data and operating context to improve availability, informing maintenance strategy, spares holdings and design changes.
Used in: What a reliability engineer does, and what the role is not
Remote terminal unit (RTU)Data and software
A controller for remote sites in a SCADA system that reads and drives local inputs and outputs, runs local logic and communicates over long distance links, with time stamped events and store and forward when the link drops.
Used in: PLC, DCS and SCADA compared: what each does, where control lives, and how to choose for a plant or a network of remote sites
Reorder pointMaintenance and reliability
The stock level that triggers a new order, also called the min: the usage expected during the lead time plus a safety stock. The max is the reorder point plus the order quantity.
Used in: Spare parts and MRO inventory management: classes of stock, min and max levels, the catalogue, kitting, and slow moving stock
Replacement in kindMaintenance and reliability
A replacement with an item of the same make, model, rating and material, fitted the same way, so that the design basis has not moved. It needs a work order and no management of change. A different maker's equivalent, rating, material or setting is a change.
Used in: Obsolescence management: the stages, the ways out, what sets the risk and the register that holds it, Management of change for plant modifications: engineering change management, the test, the eight steps and the register
Report automationData and software
Producing a recurring report directly from the data each period, with its queries, tables, charts and standard text built once, so every issue has the same shape and its numbers trace to their source.
Used in: Document and report automation for engineering and maintenance: the documents that suit it, how templates work, the checks that make it safe, and where people stay in charge
Request for tender (RFT)Mechanical and structural
The invitation to submit a formal offer for defined works or services, issued with the conditions of tender, conditions of contract, scope, specification, drawings, price schedule, returnable schedules and evaluation criteria.
Used in: Tender documents and the tender process: what goes in a request for tender, what tenderers return, evaluation criteria, and what causes trouble later
Residence timeProcess plants
How long material stays in a vessel or process step. It governs reaction completion, settling and the buffer a circuit has against upsets.
Residual valueMaintenance and reliability
What an asset is worth at the end of its service with its owner: its sale or transfer value, or its scrap value, less the cost of making it safe and transportable. Booked with the disposal, and one of the inputs to a life cycle cost comparison.
Used in: Decommissioning and asset disposal: six stages from the decision to the closed records
Returnable schedulesMechanical and structural
The forms in a request for tender that each tenderer must complete and return, such as the form of tender, price schedule, departures, methodology, program, key people and insurances. What can be evaluated is what they ask for.
Used in: Tender documents and the tender process: what goes in a request for tender, what tenderers return, evaluation criteria, and what causes trouble later
Reverse engineeringDEM and scanning
Recreating accurate drawings and models of existing equipment, commonly from 3D scans, so parts can be manufactured or modified when original documentation is missing.
Risk based inspection (RBI)Maintenance and reliability
A method for setting the inspection scope, technique and interval of static equipment such as vessels, piping and tanks from the likelihood and consequence of each degradation mechanism, rather than from a fixed calendar. API RP 580 describes it.
Used in: Asset integrity management: what it covers, the standards behind it, and how it fits with maintenance
Risk matrixMaintenance and reliability
A grid that plots the consequence of an event against its likelihood, usually five by five, so each combination carries a score and a band. In maintenance it is the usual way to rank asset criticality, taking the worst consequence across safety, environment, production and cost.
Used in: ISO 55001 explained: what the asset management standard requires, and what changed in 2024, FMECA: how to run a failure modes, effects and criticality analysis
Risk priority number (RPN)Maintenance and reliability
Severity multiplied by occurrence multiplied by detection, used to rank failure modes in an FMEA. It is simple, but different risks can share the same number, so many methods now rank by severity and criticality first.
Used in: FMECA: how to run a failure modes, effects and criticality analysis
Rock boxBulk materials handling
A chute feature that deliberately traps a bed of material so the incoming stream impacts on rock rather than steel, trading flow control for wear life.
Used in: Chute liners: how transfer chutes wear, liner materials and where each belongs, laying out liners, and planning changes from measured wear
Root cause analysis (RCA)Maintenance and reliability
A structured investigation of why a failure happened, carried past the broken part and the person nearest it to the condition in the system that let it happen, so the actions stop it recurring. IEC 62740 is the standard for the method. For equipment failures the causes sit at three levels: physical, human and latent.
Used in: Bearing failure analysis: why bearings fail early, the six ISO 15243 failure modes, the common causes and their signs, and examining a failed bearing, Fault tree analysis: building the tree from the top event, gates and minimal cut sets, and where it sits beside FMECA and RCA, What a reliability engineer does, and what the role is not, Root cause analysis for equipment failures: finding the cause you can actually fix
RopingProcess plants
A hydrocyclone underflow leaving the spigot as a solid rope rather than a hollow spray, because the spigot is overloaded and the air core has collapsed. Coarse material is then forced to the overflow.
Used in: Hydrocyclones: how a cyclone classifies, what moves the cut size, spray and roping, and maintaining a cyclone cluster
RotableMaintenance and reliability
A repairable item managed as a pool: one in service, one on the shelf, the failed one repaired on exchange and returned to the shelf. Halves the holding for pumps, gearboxes and motors where the repair turnaround is shorter than the next expected failure.
Used in: Spare parts and MRO inventory management: classes of stock, min and max levels, the catalogue, kitting, and slow moving stock, Critical spares: deciding what to stock, and what to accept the risk on
Run of mine (ROM)Mining
Material as it comes from the pit or underground, before any crushing or processing. ROM pads are the buffer between mining and the plant.
Used in: Apron feeders: how they work, the capacity calculation, design points at the hopper and discharge, and the wear and maintenance of each part
Run to failureMaintenance and reliability
A deliberate decision to do no preventive maintenance on an item and to repair or replace it when it fails, taken because the failure has no safety, production or cost consequence worth a task, or because no task would reduce the chance of it. The decision is recorded and the spare is on the shelf, which is what separates it from neglect.
Used in: Types of maintenance compared: preventive, predictive, condition based, corrective and run to failure

S

Safety critical element (SCE)Maintenance and reliability
Any part of a facility, including software, whose failure could cause or contribute substantially to a major accident, or whose purpose is to prevent or limit the effect of one. Each carries a performance standard and the assurance tasks that prove it is met.
Used in: OT security for plant systems: zones, conduits and the controls that fit a plant, Asset integrity management: what it covers, the standards behind it, and how it fits with maintenance
Safety stockMaintenance and reliability
Stock held above the expected usage during the lead time to cover usage that runs higher than average or a delivery that arrives late. It grows with the variability of usage and lead time and with the service level wanted.
Used in: Spare parts and MRO inventory management: classes of stock, min and max levels, the catalogue, kitting, and slow moving stock
SCADAData and software
Supervisory control and data acquisition. Software on servers and workstations that supervises PLCs and RTUs spread over a wide area, gathering data, raising alarms, storing history and sending commands and setpoints, while the remote devices do most of the control.
Used in: PLC, DCS and SCADA compared: what each does, where control lives, and how to choose for a plant or a network of remote sites
Scheduled downtimeMaintenance and reliability
Time a plant was not meant to run: planned maintenance, shutdowns, no demand, no crew. Taken out of calendar time before availability is measured, which is why what counts as scheduled is decided and written down before the first downtime event is recorded.
Used in: Downtime tracking: the time model, the codes and the log that make the hours add up
Scope freezeMaintenance and reliability
The signed decision that a shutdown's scope register is now the scope. Anything added after it goes through one approval path and is counted as scope growth. Set by the longest lead time in the scope, commonly four to six months before a major event.
Used in: Shutdown planning: the checklist, the scope freeze and the schedule that holds
Scoping studyMining
The first study of a project: an order of magnitude technical and economic assessment that decides whether the project is worth studying further. In mineral reporting under the JORC Code it cannot be used to support ore reserves.
Used in: Engineering study phases: scoping, prefeasibility, feasibility and FEED, the gates between them, and the design reviews that catch problems early
Screen blindingMechanical and structural
Apertures on a vibrating screen closed off, usually by moist fines coating the panels, so material that should pass is carried over the deck.
Used in: Vibrating screens and screen panels: screen types, the parts, panel materials, blinding and cracking, and the maintenance that keeps sizing right
Seal flush planProcess plants
A standard arrangement of piping and equipment that controls the liquid at a mechanical seal's faces, such as a flush from discharge, a clean outside flush or a barrier reservoir. The plans are numbered in API 682.
Used in: Mechanical seals: how they work, cartridge and dual seals, flush and barrier plans, how seals fail, and fitting them so they last
SecretsData and software
Passwords, keys and tokens that let software reach other systems. They belong in a protected store or in environment settings, never in the code itself, where anyone with a copy can read them.
Used in: Taking a vibe-coded prototype to production
Shaft alignmentMaintenance and reliability
Positioning two coupled machines so their shaft centrelines are collinear at running conditions. Misalignment is measured as offset and angle at the coupling, in the vertical and horizontal planes, and corrected with shims and by moving the machine sideways.
Used in: Bolt torque and bolted joints: preload, where the torque goes, an indicative torque table, tightening methods, and why joints come loose, Industrial gearbox maintenance: lubrication, routine checks, oil analysis, gear and bearing failure modes, and mounting and alignment, Shaft alignment: offset and angle, tolerances by speed, soft foot, laser and dial methods, and the correction at the feet
Shift handoverMaintenance and reliability
The structured passing of the plant from one shift to the next, done face to face where possible and backed by the shift log, covering safety, isolations, plant status, work in progress, defects, production and instructions.
Used in: Shift logs and shift handover: what to record, the structured handover, and getting the log to feed the systems that act on it
Shift logMaintenance and reliability
The running record kept during a shift of what changed on the plant, what was found and what was decided: status changes, defects, isolations, alarms and trips, production and instructions, each with a time, an equipment tag and who made it.
Used in: Shift logs and shift handover: what to record, the structured handover, and getting the log to feed the systems that act on it
ShutdownMaintenance and reliability
A planned stop of a continuous operation to do the work that cannot be done while it runs: relines, liner and media changes, vessel inspections, tie-ins and statutory work. Called a turnaround in oil and gas and an outage in power.
Used in: Conveyor belt splicing: hot and cold vulcanised and mechanical splices, how a stepped splice is made, splice faults, and the register that finds them early, Shutdown planning: the checklist, the scope freeze and the schedule that holds
Single line diagramMaintenance and reliability
A drawing that represents a three-phase electrical system with one line per circuit, from the supply through the switchgear, transformers and buses to the loads, with every device identified and rated. Also called a one-line diagram. Isolation planning, protection coordination, arc flash studies and electrical maintenance are done from it. A schematic, which shows every wire of one circuit, is not one.
Used in: Motor starters compared: direct on line, star delta, soft starters and variable speed drives, and the motor control centre they sit in, Single line diagrams explained: how to read one, what it has to carry, and the work that is done from it
Site acceptance test (SAT)Maintenance and reliability
The test of a system after installation on site, connected to the real field devices, power and networks and the other systems it works with. It repeats the parts of the factory acceptance test the installation could have affected and adds the loop checks and the communications the factory could not test. It is the gate to commissioning with process material.
Used in: Writing a technical specification: how open to make it, its sections, the parts of a good requirement, and the maintenance requirements usually missed, Factory and site acceptance testing: what each proves, and how to write a test that tests the design
SkirtboardBulk materials handling
The side walls and sealing arrangement at a conveyor loading point that contain the material and settle it onto the belt while limiting dust and spillage.
Used in: Apron feeders: how they work, the capacity calculation, design points at the hopper and discharge, and the wear and maintenance of each part, Bulk materials handling: specifying a conveyor or chute so the design holds up
Slew bearingMining
The large rolling bearing that carries the upper structure of a stacker, reclaimer, crane or excavator and lets it rotate. Its tilt clearance is measured and trended to plan its replacement.
Used in: Stacker reclaimers: the machine types, stacking methods and blending, the systems on each machine and how they fail, and structural integrity
Snub pulleyBulk materials handling
A conveyor pulley placed close to the drive pulley to increase the angle of wrap of the belt around it, and so the tension the drive can transmit before slipping.
Used in: Conveyor pulleys and lagging: the pulley positions, how a drive pulley grips the belt, choosing lagging, how pulleys fail and what to inspect
Soft footMaintenance and reliability
A machine foot that does not sit flat on its base, so tightening the hold down bolt distorts the frame. Checked by loosening each foot in turn with an indicator on it, and corrected before alignment.
Used in: Bolt torque and bolted joints: preload, where the torque goes, an indicative torque table, tightening methods, and why joints come loose, Shaft alignment: offset and angle, tolerances by speed, soft foot, laser and dial methods, and the correction at the feet
Soft starterMaintenance and reliability
A starter that uses thyristors to ramp the voltage to a motor up to full, usually holding a set current limit, then hands over to a bypass contactor. It gives a smooth start and stop but no speed control, and the starting torque falls with the square of the voltage. Covered by IEC 60947-4-2.
Used in: Motor starters compared: direct on line, star delta, soft starters and variable speed drives, and the motor control centre they sit in
Sparkplug BData and software
An open specification from the Eclipse Foundation, also ISO/IEC 20237, that defines how MQTT carries plant data: a fixed topic namespace, a binary payload with named, typed, timestamped metrics with quality, and birth and death messages that tell every subscriber what exists. Report by exception with a known starting point.
Used in: Unified namespace explained: one structure every plant system publishes to, how the topic tree follows ISA-95, and when a UNS is worth building, Plant protocols explained: Modbus, OPC UA, MQTT and Sparkplug B, and where each belongs
StackerMining
A boom conveyor machine that builds stockpiles in a controlled pattern, managing both storage and blending.
Used in: Stacker reclaimers: the machine types, stacking methods and blending, the systems on each machine and how they fail, and structural integrity
Stage gateProcess plants
A decision point between project phases at which an owner or review panel decides to fund the next phase, send the work back or stop, based on whether the phase delivered what the decision needs.
Used in: Engineering study phases: scoping, prefeasibility, feasibility and FEED, the gates between them, and the design reviews that catch problems early
Standard operating procedure (SOP)Maintenance and reliability
A document describing a process: what is done, by whom and when, often across several roles. Work instructions describe how individual tasks within it are done.
Used in: Work instructions for maintenance: how they differ from procedures and job plans, the parts of a good step, and keeping them current
Standing work orderMaintenance and reliability
One work order left open for recurring minor work to be booked against, such as housekeeping, rather than raising an order for each instance. Used sparingly, because hours booked to a standing order carry no equipment history.
Used in: What a work order is, and how work order management actually works
Star delta starterMaintenance and reliability
A reduced voltage starter that starts a motor with its windings in star, then switches them to delta for running. Starting current and torque both fall to about a third of the direct on line values. Needs a motor with six leads.
Used in: Motor starters compared: direct on line, star delta, soft starters and variable speed drives, and the motor control centre they sit in
Star schemaData and software
A dimensional modelling pattern with a central fact table of measurements surrounded by dimension tables of context, designed for fast and understandable analysis.
Used in: Automated operations reporting, SQL data platform and ETL optimisation
Strangler fig patternData and software
A way of replacing a system incrementally. A routing layer is put in front of the old system and functions are rebuilt one at a time behind it, with requests moved to the new system as each is ready, until the old system can be switched off.
Used in: Legacy system modernisation: finding out what you have, the options from retain to replace, and moving off it one function at a time
Strategic asset management plan (SAMP)Maintenance and reliability
The document that converts organisational objectives into asset management objectives and sets the approach for developing asset management plans. ISO 55001 requires one, and it is the level above the asset management plans themselves.
Used in: Asset lifecycle management: the stages, the decisions at each, and the cost that follows them, ISO 55001 explained: what the asset management standard requires, and what changed in 2024, The asset management plan, and the strategic asset management plan it comes from, Asset management planning and the system behind it
Surge binProcess plants
A buffer bin between process steps that absorbs variation in feed rate so downstream equipment can run steadily.
Used in: Bulk materials handling: specifying a conveyor or chute so the design holds up
System curveMechanical and structural
The head a piping system needs at each flow: the static lift plus friction losses that rise with the square of the flow. It moves when valves, levels or pipework change.
Used in: Centrifugal pumps and pump curves: the operating point, best efficiency point, affinity laws, cavitation and NPSH, and running in the wrong place
System integrationData and software
Making separately built or supplied systems work together as one, so that data entered or measured in one is available, correct and on time in the others. On an industrial site it spans the control systems, historian, MES, CMMS and ERP.
Used in: System integration for plant systems: the interfaces between the plant and the business, the three patterns, and how an integration project is run

T

Tag numberMaintenance and reliability
The identifier given to a position in the plant, used on drawings, in the control system, in the CMMS and on a plate fixed to the equipment. It names the place, not the machine, so it stays the same when the equipment in it is replaced.
Used in: Asset tagging and equipment numbering: what a tag identifies, site conventions and IEC 81346, and how to retag an operating plant
TailingsMining
The residue left after the valuable mineral has been extracted, usually a slurry pumped to a storage facility. Management is a major safety and environmental obligation.
Take-upBulk materials handling
The device that keeps a conveyor belt tensioned and takes up its stretch: a gravity weight on a pulley in a loop of the return belt, a screw at the tail, or a winch.
Used in: Conveyor belt splicing: hot and cold vulcanised and mechanical splices, how a stepped splice is made, splice faults, and the register that finds them early, Conveyor pulleys and lagging: the pulley positions, how a drive pulley grips the belt, choosing lagging, how pulleys fail and what to inspect
Task listMaintenance and reliability
In SAP PM, the standard job plan: operations, trades, durations and parts for a piece of work, kept as a general task list or against one equipment or functional location, and used by orders and maintenance plans.
Used in: SAP PM explained: functional locations and equipment, task lists and maintenance plans, the work order cycle and statuses, and the master data that makes it work
Technical specificationMechanical and structural
The document stating the requirements an item, system or service must meet: what it must do, how well, under which conditions and to which standards, with how each requirement will be verified. It becomes part of the contract.
Used in: Tender documents and the tender process: what goes in a request for tender, what tenderers return, evaluation criteria, and what causes trouble later, Writing a technical specification: how open to make it, its sections, the parts of a good requirement, and the maintenance requirements usually missed
Technically complete (TECO)Maintenance and reliability
The SAP PM order status set when the work is finished and the notification's codes are completed. The order can no longer take work, though costs can still settle before it is closed.
Used in: SAP PM explained: functional locations and equipment, task lists and maintenance plans, the work order cycle and statuses, and the master data that makes it work
Temporary changeMaintenance and reliability
A modification made for a limited time: a bypass of a trip, a jumper, a blank, a forced value. It receives the same review as a permanent change, an expiry date on the register and on the equipment, and a recorded reversal. Temporary changes that became permanent by default are a common thread in incident investigations.
Used in: Management of change for plant modifications: engineering change management, the test, the eight steps and the register
Thermal growthMaintenance and reliability
The change in a machine's shaft height or position as it warms to running temperature. Allowed for by setting deliberate offsets in the cold alignment.
Used in: Shaft alignment: offset and angle, tolerances by speed, soft foot, laser and dial methods, and the correction at the feet
ThickenerProcess plants
A large settling vessel that concentrates a slurry by allowing solids to settle, recovering water from the overflow for reuse.
Used in: Thickeners: how they work, the types and parts, rake torque and the variables to watch, common problems, and maintaining a thickener
ThroatbushProcess plants
The suction side liner of a slurry pump, facing the front of the impeller. The gap between throatbush and impeller is adjusted as both wear, to limit recirculation.
Used in: Slurry pumps: how they are built, what drives wear, liner materials, gland and mechanical seals, and planning wet end changes
ThroughputProcess plants
The rate material passes through a system, usually tonnes per hour. Sustained throughput, not peak, is what determines production.
Used in: Real-time production analytics
Torque armMechanical and structural
The arm that stops a shaft mounted gearbox rotating with the shaft it drives, anchored to the structure through bushes and pins that wear and need inspecting.
Used in: Industrial gearbox maintenance: lubrication, routine checks, oil analysis, gear and bearing failure modes, and mounting and alignment
Traceability and genealogyData and software
Recording which batches, lots or stockpiles of material went into each product or shipment, and through which steps, so a quality problem can be traced back to its source and forward to everything it affected. A core MES function.
Used in: MES explained: what a manufacturing execution system does, where it sits between the ERP and the control systems, and what it is called in mining and process plants
Training idlerBulk materials handling
An idler set mounted on a central pivot that swings when the belt moves off centre, skewing its rolls to steer the belt back. Also called a self-aligning idler. It corrects small drift but not the cause.
Used in: Conveyor belt tracking and maintenance: the tracking rule, finding the cause of mistracking, training a belt, and the inspections that keep conveyors running
TrajectoryBulk materials handling
The path the material stream follows as it leaves a conveyor head pulley. It sets where the stream enters the chute and is the starting point of transfer design.
Used in: Bulk materials handling: specifying a conveyor or chute so the design holds up, What DEM modelling actually tells you about transfer chute design
Tramp metalMining
Uncrushable metal in the feed, such as bucket teeth, drill steel and liner bolts, that can damage crushers and belts. It is removed ahead of the crusher by magnets and metal detectors.
Used in: Crusher maintenance and liners: wear parts by crusher type, the closed side setting, routine checks, and planning liner changes from measured wear
Troughing idlerBulk materials handling
An idler set on the carrying side of a belt conveyor with a centre roll and two inclined wing rolls that form the belt into a trough to carry more material and keep it on the belt.
Used in: Conveyor belt tracking and maintenance: the tracking rule, finding the cause of mistracking, training a belt, and the inspections that keep conveyors running

U

Ultrasound monitoringMaintenance and reliability
Detecting sound above the range of human hearing to find compressed air and gas leaks, valves passing, electrical discharge and bearing friction. It is widely used on greasing routes, where the technician lubricates until the reading falls.
Used in: Condition monitoring: techniques, intervals and building a program that works
Unified namespace (UNS)Data and software
An architecture where every system publishes its current data to one shared, structured namespace, usually on an MQTT broker with topics named after the ISA-95 equipment hierarchy, and any system that needs the data subscribes to it.
Used in: Unified namespace explained: one structure every plant system publishes to, how the topic tree follows ISA-95, and when a UNS is worth building

V

Verification methodMechanical and structural
How compliance with a requirement will be shown: inspection, analysis, demonstration or test. Choosing it when the requirement is written makes the acceptance test plan possible.
Used in: Writing a technical specification: how open to make it, its sections, the parts of a good requirement, and the maintenance requirements usually missed
Vibe codingData and software
Building software by describing what you want to an AI coding tool and steering by whether the result works, without necessarily reading the code it writes. Fast, and well suited to prototypes. The term dates from early 2025.
Used in: Taking a vibe-coded prototype to production
Vibration analysisMaintenance and reliability
Measuring and analysing the vibration of machinery, usually at the bearing housings, to detect faults such as imbalance, misalignment, looseness and bearing or gear defects. Overall levels show that something has changed, and the frequency spectrum shows what.
Used in: Shaft alignment: offset and angle, tolerances by speed, soft foot, laser and dial methods, and the correction at the feet, Electrical preventive maintenance: the program along the power path, from the supply to the motors, Condition monitoring: techniques, intervals and building a program that works
Von Mises stressMechanical and structural
A single equivalent stress value combining the stress components at a point, compared against yield strength to judge whether ductile material will deform permanently.
Vulcanised spliceBulk materials handling
A conveyor belt splice in which the layers of the two belt ends are bonded with rubber, either cured under heat and pressure in a press (hot) or with an adhesive that cures at ambient temperature (cold).
Used in: Conveyor belt splicing: hot and cold vulcanised and mechanical splices, how a stepped splice is made, splice faults, and the register that finds them early

W

Wall friction angleDEM and scanning
The friction between a bulk solid and a specific wall or liner material. It is measured, not assumed, and directly determines the hopper angle needed for mass flow.
Used in: Bulk materials handling: specifying a conveyor or chute so the design holds up, What DEM modelling actually tells you about transfer chute design, Transfer chute redesign guided by DEM modelling
Weibull distributionMaintenance and reliability
The distribution most used to describe how failures spread over an asset's life. Its shape parameter says whether failures fall with age (below 1), are random (1) or rise with age (above 1), and its scale parameter is the characteristic life, the age by which 63.2 per cent of a population has failed.
Used in: The bathtub curve is one of six: failure patterns, Weibull and the reliability block diagram
Whole of life costMaintenance and reliability
The total cost of owning an asset across its life, from acquisition through operation, maintenance and renewal to disposal. The cheapest asset to buy is often not the cheapest to own.
Used in: Asset lifecycle management: the stages, the decisions at each, and the cost that follows them, ISO 55001 explained: what the asset management standard requires, and what changed in 2024, The asset management plan, and the strategic asset management plan it comes from, Asset management planning and the system behind it
Work instructionMaintenance and reliability
A document that tells the person doing a task how to do it, step by step: one action per step, the key point that makes it done right and why, any value with its source, a picture and a check. It covers one task on one kind of equipment.
Used in: Document and report automation for engineering and maintenance: the documents that suit it, how templates work, the checks that make it safe, and where people stay in charge, Work instructions for maintenance: how they differ from procedures and job plans, the parts of a good step, and keeping them current
Work samplingMaintenance and reliability
A way of measuring how time is spent by making many instant observations at random times and recording each in one category. The share of observations in a category estimates the share of time. Used for wrench time studies, where about 900 observations give a result within three percentage points.
Used in: Wrench time: what counts, measuring it with a work sampling study, where the shift goes, and how planning and kitting raise it
Wrap angleBulk materials handling
The angle through which a conveyor belt wraps a pulley. On a drive pulley, the tension it can transmit rises exponentially with the wrap angle and the friction coefficient.
Used in: Conveyor pulleys and lagging: the pulley positions, how a drive pulley grips the belt, choosing lagging, how pulleys fail and what to inspect

Y

Yield strengthMechanical and structural
The stress at which a material stops behaving elastically and takes permanent deformation. Most structural design keeps working stresses safely below it.
Used in: Structural design and certification of transport frames

Z

Zones and conduitsData and software
The structure IEC 62443 uses to secure a plant. A zone is a group of assets with the same security requirement, by function and consequence. A conduit is the path between two zones, with the devices, protocols and ports that may use it named and enforced by a firewall. The industrial DMZ is the only conduit between the plant and the business.
Used in: Unified namespace explained: one structure every plant system publishes to, how the topic tree follows ISA-95, and when a UNS is worth building, OT security for plant systems: zones, conduits and the controls that fit a plant