COMMINUTION & CRUSHING
NAIPU Mining Machinery’ s custom φ10.37 × 2 m SAG mill test platform
‘ Duty-based prediction’ for mill liners
Jiangxi Naipu Mining Machinery Co., Ltd( NAIPU Mining Machinery) is an integrated provider of core mineral processing equipment and wear solutions for global mining operations, with capabilities spanning R & D, manufacturing, sales and service. The company was listed on the Shenzhen Stock Exchange in 2020. Focusing on the key unit operations of grinding and classification, NAIPU offers end-to-end technical support – from equipment selection and duty matching to process optimisation advisory – helping concentrators improve availability, reduce unplanned downtime and lower total operating costs.
NAIPU Mining Machinery’ s core strength lies in material-structure co-innovation. The company has long specialised in high-performance rubber wear materials and rubber-based composite solutions, advancing reliability and service life through continuous material system upgrades. In parallel, NAIPU works to improve the energy efficiency of grinding circuits in support of energy-saving and emission-reduction goals. Its products and solutions cover composite liners for large SAG and ball mills( including high-alloy forged composite liners), slurry pumps and wet-end parts, hydrocyclone clusters and wear parts, trommel screens, rubber composite pipelines, screen panels, and related components – providing more complete package capability for the grinding – classification circuit.
In the mill liner segment, NAIPU Mining Machinery’ s high-alloy forged composite liner, launched in 2025, follows a“ forged alloy + rubber composite” structural route. It is designed to combine structural stability under high-impact duty with the lightweight advantages of composite liners. Guided by measurable outcomes – including service life, energy consumption and maintenance windows – the solution targets quantifiable performance gains for large SAG milling
48 applications.
“ NAIPU Mining Machinery notes that, with increasing mill size and declining ore grindability, conventional cast Cr-Mo steel liners are more prone to amplified material consistency and defect risks in large sections – leading to life variability, abnormal breakage and unplanned downtime,” the company says.“ As a result, the evaluation focus is shifting from‘ how long it lasts’ to‘ whether it makes the grinding system more controllable and predictable’.
Against this backdrop, NAIPU Mining Machinery has focused its development on SAG mill composite liners, aiming to address the trade-off between impact duty and energy efficiency through material – structure synergy. To support this, the company has built a φ10.37 × 2 m SAG mill test platform and combined discrete element modelling simulation capabilities with wear-scan calibration, moving liner design beyond“ experience-based iteration” toward“ duty-based prediction” of impact energy distribution and wear behaviour.
The company added:“ NAIPU Mining Machinery proposes a manufacturing route that uses forging to reduce castingdefect risk – without taking the high-cost path of fully forged metal liners.” Instead, it integrates a forged high-alloy section with a rubber composite structure to form a highalloy forged composite liner. The intent is to combine the impact resistance of forged material with the lightweight advantages of a composite structure in a single design.“ In high-impact duty, this approach reduces individual liner weight and helps maintain key profile geometry over the wear cycle, supporting lower operating variability and improved mill stability and efficiency,” the company notes.
After four years of development, the company completed and commissioned its first set of high-alloy forged composite SAG liners in 2024.
NAIPU argues that the validity of a new
liner route should ultimately be judged by system-level outcomes, not single-point metrics. In its 2025 roll-out applications, the company highlights five areas of combined improvement: extended liner life; higher mill throughput; lower specific energy consumption; stable operation; faster change-outs.
At a large copper-gold operation running a φ7.5 × 3.2 m SAG mill, the original cast metal liners typically achieved a service life of around 105 days. After modifications by other suppliers, the best campaign life with Cr-Mo alloy liners reached 126 days, but liner life remained variable and abnormal breakage caused downtime. At an elevation of over 4,000 m, frequent liner changeouts had become a significant disruption to concentrator operations.
Following an assessment of site duty and operating conditions, NAIPU Mining Machinery proposed a forged-liner solution. The first set of high-alloy forged composite liners achieved a service life of 232 days – an increase of 106 days versus the best performance previously achieved with cast metal liners. Total ore processed increased from 0.897 Mt to 1.793 Mt(+ 100 %), while average throughput rose from 307.4 t / h to 334.7 t / h(+ 8.8 %). Specific energy decreased from 8.921 kWh / t to 7.776 kWh / t(-12.8 %), and grinding media consumption fell from 0.462 kg / t to 0.431 kg / t(-6.7 %). NAIPU Mining Machinery attributes the simultaneous reductions in energy and media consumption to the lower overall mass of the forged composite liners compared with conventional Cr-Mo metal liners, resulting in reduced mill load.
In another copper operation with a φ10.37 × 5.19 m SAG system, the original metal liners delivered a service life of about 120 days. NAIPU Mining Machinery’ s full set of high-alloy forged composite shell liners was put into service on August 23, 2025, and, as of 18 February, has operated steadily for 171 days. Based on the latest on-site liner wear assessment, the current set is expected to run to approximately 201 days. During the campaign, mill throughput increased noticeably, while power consumption and grinding media consumption both showed reductions to varying degrees, indicating a clear, direct impact of the upgraded material route on energy and consumables performance.
By the end of 2025, NAIPU Mining Machinery’ s high-alloy forged composite liners had completed application validation in more than 10 mine sites, with an expanding range of ore types and mill sizes. The company concluded:“ From single-site trials to repeat orders across multiple mines, the approach is moving from‘ feasible’ toward a stage of scalable deployment.”
International Mining | MARCH 2026