For Coal Wash Plant Reliability and Maintenance
Coal Handling and Preparation Plants (CHPPs) form the backbone of Australia’s coal production network — from the Bowen Basin to the Hunter Valley and the Central West. Yet these plants face relentless mechanical and environmental challenges. Every tonne of coal that passes through generates impact, vibration, slurry, and corrosion — all of which degrade mechanical systems and shorten asset life.
At Hamilton By Design, we specialise in helping operators and contractors transition from reactive maintenance to precision-based, data-driven engineering. Through advanced 3D scanning, mechanical design, finite element analysis (FEA), and practical shutdown planning, our goal is simple: design for reliability, maintain for efficiency, and execute for safety.
1. Designing for Reliability
Most unplanned failures in a coal wash plant can be traced back to early design decisions. Poor geometry in chutes, undersized bearings, or inadequate access provisions make routine maintenance more difficult and increase safety risks. The starting point for reliability is a mechanical design that aligns with plant realities:
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Ease of access and installation: Every component should be replaceable without cutting, grinding, or excessive crane time.
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Defined load paths: Support structures, monorails, and lifting lugs should be rated and certified under AS 4991 Lifting Devices.
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Material selection: Use quenched and tempered steel (e.g. Bisalloy) in high-impact zones and lighter wear materials (rubber, ceramic, UHMWPE) where abrasion dominates.
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Design compliance: Reference AS 1418 (Cranes, Hoists & Winches) and AS 4100 (Steel Structures) for any interfaces involving lifts, frames, or platforms.
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Constructability focus: Consider how each component will be installed, aligned, and torqued during a shutdown, not just how it performs in theory.
A well-designed plant doesn’t just last longer — it’s easier and safer to maintain, which means less time offline and more consistent throughput.
2. The Role of Regular Inspections in Corrosive CHPP Environments
Coal and water are a dangerous combination for steel. Over time, the interaction of moisture, oxygen, and fine coal particles creates a mildly acidic environment, especially in sumps, under conveyors, and around wet chutes or launders. This acidity accelerates corrosion, particularly on untreated or aging steelwork.
Regular inspection is therefore the most powerful preventive tool in CHPP maintenance. It’s not just about finding rust — it’s about identifying where corrosion will occur next.
Effective inspection programs include:
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Daily operator checks: Visual walk-arounds to spot early staining, pitting, or flaking coatings.
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Weekly mechanical reviews: Checking bolt tension, bearing temperature, and visible steel condition.
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Quarterly or shutdown inspections: Ultrasonic thickness testing on chutes, hoppers, and frames to track material loss.
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Annual 3D scanning campaigns: Comparing LiDAR models taken months apart to measure deformation and quantify corrosion over time.
These inspections reveal weak points long before failure occurs. When combined with a structured maintenance schedule, they prevent unplanned shutdowns, reduce emergency welding, and extend the life of key structural assets.
3. Data-Driven Maintenance and Condition Monitoring
Gone are the days when experienced operators relied purely on “listening to the plant.” Today, modern CHPPs use real-time data acquisition to monitor vibration, temperature, load, and alignment. But human senses still play a vital role — a trained ear or touch can detect imbalance and overheating that instruments might miss.
The best maintenance strategies blend both approaches:
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Motor load tracking detects overloading on conveyors, screens, and pumps.
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Vibration analysis identifies bearing fatigue, misalignment, or imbalance before catastrophic failure.
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Infrared thermography highlights hot bearings and electrical faults invisible to the naked eye.
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Ultrasonic testing and thickness gauging provide a measurable indication of steel degradation, especially in wet, acidic areas.
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3D LiDAR scanning visualises wear zones and helps engineers create accurate “digital twins” for comparison across time.
These digital twins allow maintenance planners to pinpoint deformation, misalignment, or structural movement down to millimetre precision — transforming the CHPP into a living mechanical system that can be analysed and optimised continuously.
4. Scan-to-Model Precision Engineering
Every coal wash plant evolves over time — upgrades, patch welds, retrofits, and pipe reroutes all cause the as-built layout to drift from the original drawings. That’s where 3D scanning becomes essential.
High-definition LiDAR captures millions of data points, recreating the plant in precise digital form. Engineers can then model new chutes, screen decks, or pump bases directly within the scanned environment to:
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Validate fit-up tolerances before fabrication.
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Confirm lifting paths and crane clearances.
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Verify bolt access and maintenance envelopes.
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Overlay FEA results on the as-built geometry for fatigue and stress validation.
This scan-to-model approach eliminates costly surprises during shutdowns. By resolving interferences virtually, projects achieve faster installation times, fewer clashes, and minimal rework.
5. Finite Element Analysis (FEA) for Structural Assurance
CHPP components endure cyclic loads, vibration, and impact — all prime conditions for fatigue failure. Finite Element Analysis (FEA) allows engineers to simulate these conditions in a virtual environment.
Typical boundary conditions include:
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Static loads: Dead weight of chutes, liners, and supporting frames.
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Dynamic forces: Screen exciters, slurry impact, and conveyor discharge trajectories.
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Support stiffness: Bolted bases or gusseted connections with realistic compliance.
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Modal analysis: Identifying natural frequencies and avoiding resonance near operating speeds.
By evaluating stress concentrations, weld toe fatigue, and deflection limits, engineers can predict life expectancy and optimise reinforcement. In practice, FEA-based validation reduces over-engineering while ensuring safety compliance — particularly under Australian Standards.
6. Smart Wear Management and Material Selection
Wear is inevitable in coal preparation plants, but premature wear is preventable. The correct wear lining can double or even triple component lifespan. Material choice depends on particle size, density, velocity, and impact energy — all of which dictate how energy is transferred during collisions.
Typical solutions include:
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Quenched & tempered steel (e.g. Bisalloy) for high-impact loading zones such as chute lips or transfer points.
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Rubber or polyurethane linings for abrasion under low to moderate impact.
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Ceramic tiles in high-velocity or high-temperature zones for excellent hardness and longevity.
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UHMWPE (ultra-high-molecular-weight polyethylene) for low-friction, non-stick surfaces.
An integrated wear-management plan combines condition monitoring, liner mapping, and service-life tracking to forecast when replacement should occur — preventing failures rather than reacting to them.
7. Pumping and Slurry Transfer Systems
Slurry transport is one of the most maintenance-intensive systems in a wash plant. Pipelines must balance velocity high enough to avoid settling with low enough wear to preserve liners and reduce energy use.
Key mechanical considerations include:
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Critical velocity: Maintaining 1.2–1.5× the settling velocity for the slurry type.
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Pipe material: Rubber-lined steel for coarse solids; HDPE for fines or corrosive conditions.
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Head loss and pump selection: Balancing static and friction losses while ensuring sufficient Net Positive Suction Head (NPSH).
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Elbow design: Long-radius bends reduce turbulence and localised wear.
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Instrumentation: Pressure taps, flow sensors, and vibration alarms for predictive monitoring.
With proper design and inspection, slurry systems can run reliably for years, with predictable replacement schedules instead of costly mid-campaign failures.
8. Conveyor Transfer Design and Particle Trajectory
A common source of dust, spillage, and liner wear in CHPPs lies in poorly designed transfer points. Understanding particle trajectory — the path and velocity at which material leaves one conveyor and enters a chute — is fundamental to mechanical efficiency.
Well-engineered transfers:
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Match the material stream to the receiving chute curvature.
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Minimise drop height and impact angle.
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Incorporate impact beds, skirting systems, and wear liners.
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Control dust through controlled flow and enclosure design.
Using trajectory modelling and 3D scanning, engineers can predict exactly how material will behave — improving throughput, reducing clean-up, and extending the life of belts and liners.
9. Shutdown Planning and Pre-Fabrication QA
Shutdowns are high-pressure events where planning equals performance. A successful mechanical shutdown doesn’t begin on day one — it starts months earlier with design validation and fabrication quality checks.
Before any new chute or structure reaches site, engineers should confirm:
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Lifting compliance: Lugs rated to AS 4991, with centre of gravity marked and rigging plans approved.
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Fit-up accuracy: Scan-to-model verification to ensure tolerance within ±2–5 mm.
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Fastener integrity: Correct bolt grade, torque accessibility, and alignment.
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Coating and liner QA: Correct material, cure time, and installation sequence.
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Trial assembly: Ground trial or partial fit to validate alignment before shipment.
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Documentation: ITPs, weld maps, NDT reports, coating certificates, and as-built models delivered before mobilisation.
The result is confidence — everything fits, everything lifts safely, and everything performs as expected.
10. Integrating Safety, Engineering, and Operations
Mechanical reliability is inseparable from safety. Failures of worn chutes, cracked supports, or seized bearings not only halt production but endanger lives.
Integrating engineering design, maintenance, and operations into a shared feedback loop is the hallmark of a mature CHPP. Operators provide condition data, engineers refine designs based on site feedback, and planners adjust maintenance intervals based on performance data.
This closed-loop approach, often referred to as Digital Engineering in Maintenance, underpins the next generation of CHPP optimisation — where 3D models, scanning data, and maintenance histories all live within a single digital environment.
11. The ROI of Engineering-Led Maintenance
Transitioning from reactive to predictive maintenance produces measurable returns.
Typical improvements seen across similar Australian wash plants include:
| Category | Typical Improvement | Example Outcome |
|---|---|---|
| Unplanned downtime | 20–40% reduction | Fewer emergency shutdowns |
| Liner lifespan | 30–50% increase | Longer change-out intervals |
| Safety incidents | 25% reduction | Fewer reactive tasks in confined spaces |
| Fabrication rework | 60–80% reduction | Fit-first-time installations |
| Shutdown duration | 10–20% shorter | More production hours per year |
These gains demonstrate why combining mechanical engineering, digital scanning, and structured maintenance is not a cost — it’s an investment.
12. Confidence Through Engineering Discipline
Coal wash plants will always be demanding environments. Yet through smarter design, continuous inspection, and disciplined maintenance, reliability and safety can be engineered into every tonne of coal produced.
At Hamilton By Design, we combine SolidWorks modelling, FEA validation, LiDAR scanning, and mechanical design expertise to help site teams achieve practical, data-driven reliability. Whether it’s a structural upgrade, chute redesign, or complete plant model, our process ensures each project is safe to lift, easy to install, and built to last.
