Mining: fixed plant integrity in abrasive service

Fixed plant on a mine site wears out rather than corrodes. Slurry moves through pipe at velocities that strip millimeters of steel from a bend extrados in months. Mill liners, chute liners, cyclone spigots, and pump casings are consumables with a life measured in operating hours. At the same time the site carries statutory pressure equipment (autoclaves, acid plant vessels, air receivers) whose inspection obligations under AS/NZS 3788 or the local equivalent do not care about the wear program at all. And all of this happens hundreds of kilometers from the nearest town, on a plant where the only reliable signal is in the control room. This paper is about what mining fixed plant inspection software has to do in that environment.

Why does wear change the inspection problem?

A corrosion program assumes a rate that is roughly stable over time and roughly uniform over an area, so a few readings at defined locations, compared over years, characterize the equipment. Abrasive wear breaks both assumptions:

• It is highly localized. A slurry bend wears at the extrados; a tee wears at the branch; a reducer wears at the throat. A reading a few centimeters away can be at nominal.
• It is fast. Rates of several millimeters per year are ordinary, and some duties are worse.
• It changes. A new ore body with harder gangue, a higher solids concentration, or a pump duty change can double the rate overnight.

The record therefore needs more locations per item, readings at clock positions rather than at a single point, and a short-term rate that is trusted over the long-term one. In intelliSPEC the corrosion summary computes short-term, long-term, and maximum rates with the maximum governing, and remaining life as (t minus tMin) divided by the governing rate. That is the right conservatism for wear: the fast recent rate governs. CML points carry 64 fields including grid geometry, so a bend can carry a grid of readings by clock position and axial station rather than one number, and OD and schedule, so the nominal is on the point. The intelliINTEGRITY module holds the rates and remaining life.

How should slurry piping be tracked through rotation and replacement?

Slurry spools are rotated so the worn extrados moves out of the flow path, and a rotated spool may be moved to another position or another line. If the record keys on line position, the thickness history is lost at every move. If it keys on the physical spool, the history follows the metal.

The requirements:

• Each spool has its own identity, and readings are recorded on the spool with a clock position on the spool, not on the line.
• The spool's current position in the line is a relationship that can change, with the change recorded.
• Rotation and replacement are events on the spool record, so remaining life is computed from the readings since the last rotation.
• Liner thickness (rubber, ceramic, polyurethane) is tracked where lined spools are used, since the liner is the wear element until it fails.

The asset hierarchy in intelliSPEC is a graph of nodes with roles rather than a fixed tree, so a spool can be a component node whose relationship to a line position is a graph edge that moves, while its readings stay attached to it. Instrument profiles for supported UT gauges, including the Evident 38DL Plus and DeFelsko PosiTector UTG, bring readings in over Bluetooth or keyboard wedge without retyping, and QR and barcode capture identifies the spool in the field. The tMin engine routes piping to ASME B31.3 and returns the design code and formula, and API 570 intervals are capped at half the remaining life. Where a site uses RFID tags on spools and liners, intelliTRACK and the TSL 1153 RFID reader profile identify tagged items.

What does AS/NZS 3788 require of the pressure equipment record?

AS/NZS 3788 is the in-service inspection standard for pressure equipment across Australia and New Zealand, and it is referenced by state and territory regulators. Its structure is different from API 510: equipment is assigned a hazard level from its pressure, volume, and contents, and inspection types and maximum intervals are set by hazard level and equipment type, with provision for extension where the owner can justify it. The standard is also explicit about the competence required of the inspector and about the records the owner must hold.

The record has to show:

• The equipment register with hazard level and design registration.
• Each inspection with type, date, findings, and the inspector and their competence.
• Repairs and alterations with their documentation.
• The basis for any interval extension, including the condition evidence and the assessment.
• Safety valve and protective device testing.

The competence requirement means the qualifications of the inspector are part of the equipment record. intelliCREW in intelliSPEC carries inspector qualification, skills, and training records, and the signature widget records per-signer identity even on a shared device, so the "who inspected this and were they competent" question is answered from the record. For vessels the tMin engine routes to ASME VIII Div 1 and returns the design code and formula; where a vessel was designed to AS 1210, the design minimum thickness is recorded as the tMin with its method noted, so the basis stays with the point.

What about autoclaves and hydrometallurgical plant?

Pressure oxidation and high-pressure acid leach plants carry the most demanding pressure equipment on any mine site: large brick-lined and titanium-clad autoclaves operating at high temperature and pressure in acidic, oxidizing slurry, with flash vessels, heat exchangers, and pressure letdown systems around them. The damage mechanisms include erosion-corrosion at agitator and slurry inlet regions, refractory and membrane degradation, acid attack on carbon steel behind a compromised lining, and thermal cycling.

The inspection record for an autoclave needs:

• Lining condition by zone, with brick wear and membrane condition tracked separately.
• Shell thickness behind the lining where it can be measured, and shell temperature monitoring as a proxy for lining breach.
• Nozzle, agitator, and internals condition.
• Damage mechanisms recorded as such, so the NDE scope follows them.
• Shutdown findings and repairs linked to the component.

Damage mechanisms in intelliSPEC are first-class records attached to the equipment and component, so an erosion-corrosion mechanism on an autoclave inlet zone drives the scope at the next shutdown. NDE results run through intelliNDT, and a shutdown is modeled in intelliPROJECTS as an event with activities, crews, daily progress, delay events, gate reviews, and cost entries, with findings landing on the equipment.

What does the remote site demand of the field application?

A mine site processing plant is large, noisy, dusty, and disconnected. Wifi may exist in the control room and the workshop; it does not exist inside a mill shell or on the top of a thickener. Crews work long shifts on a swing roster, and the inspection technician may be a contractor who is on site for a week and then gone.

The requirements:

• Full offline capture for forms, photos, video, and workflows, for as long as the shift or the swing lasts, with no time limit imposed by the software.
• Encrypted storage on the device, because tablets travel.
• A visible conflict record when two people touch the same spool offline.
• Photo and video bound to the component at capture time, because a wear pattern is easier to show than to describe.
• Voice capture for hands-busy work, converted to structured fields rather than left as audio.

intelliSPEC's field app captures fully offline for all inspection modules with no time limit on the local store, encrypts offline data at rest on the device, and records field-level conflicts with the local value, the remote value, who resolved it, and when. Photo and video capture (video up to 120 seconds by default), GPS location, and QR and barcode reading are built in. Spectra's voice-to-form turns speech into structured fields, with the technician confirming each field before it is saved. Visual inspections of liners, chutes, and structures run through intelliINSPECT.

How do liners and consumables fit the integrity record?

Mill liners, chute liners, cyclone components, and pump wear parts are not pressure equipment, but they are the largest fixed plant maintenance spend on most sites and their condition affects everything downstream. A liner that fails early damages the mill shell, which is a structural and sometimes a pressure boundary concern.

The record needs liner thickness by position, hours in service, and the change-out decision, on the equipment the liner protects. Because intelliSPEC is metadata-driven and tenants configure forms through the form designer, a liner inspection form with the site's own zones and thresholds is a configuration task rather than a vendor request, and completed records pin the form they were executed with so a history of change-outs stays readable after the form is revised.

How intelliSPEC handles it

For a mining fixed plant integrity team, the facts that bear on abrasive service:

• The corrosion summary reports short-term, long-term, and maximum rates with the maximum governing, which is the right conservatism when wear rates change quickly.
• CML points carry 64 fields including grid geometry, OD and schedule, so bends and spools carry readings by clock position and station.
• The asset hierarchy is a graph with roles, so spools keep their identity and history through rotation and relocation.
• Seven instrument profiles over Bluetooth or keyboard wedge, plus QR, barcode, and RFID identification of tagged items.
• Damage mechanisms are first-class records; the tMin engine routes vessels to ASME VIII Div 1 and piping to ASME B31.3 and returns the code and formula; intervals are capped at half the remaining life.
• intelliCREW carries inspector qualifications for the competence evidence AS/NZS 3788 expects.
• Full offline capture with no time limit, device encryption, field-level conflict records, and per-signer signatures on shared devices.
• Tenant-configured forms, with completed records pinned to their configuration; a hash-chained audit trail per tenant.

The mining solutions page describes the module mix for a processing plant. The evaluation that fits this industry is to load one slurry line's spool history and one autoclave's last shutdown package and see whether the next change-out and the next shutdown can be planned from the record.