How to Choose the Right Mining Chain (Round Link Chain) for Your Conveyor and Haulage System

Mining chains – specifically round link chains – are the workhorses of underground and surface mining operations. They are used in AFCs (armoured face conveyors), stage loaders, haulage systems, and bucket elevators. A failed chain in a mine does not just halt production; it can trigger catastrophic safety incidents.

Choosing the correct mining chain is therefore a critical decision. This guide explains the key parameters – grade, size, material, heat treatment, and certification – that you must evaluate to ensure both safety and productivity.

Step 1: Understand the Chain Grade – Strength and Safety

Mining chains are graded by their breaking strength and fatigue resistance. The most common grades for mining and lifting applications are:

Key point: Higher grade means higher strength for the same diameter, but also lower elongation before break. For underground coal mines, Grade 80 or Grade 100 is often required by safety regulations. Always follow the OEM or mine-site specification.

Step 2: Select the Right Chain Diameter and Pitch

The chain size is defined by the wire diameter (d) and pitch (p) – the distance between two consecutive links.

• Common mining chain sizes: 14×50, 18×64, 22×86, 26×92, 30×108, 34×126 (d×p in mm)

• Larger diameter → higher load capacity → but also heavier and requires larger sprockets.

How to choose:
Calculate the maximum working load (including shock and start-stop cycles). Multiply by a safety factor (typically 4:1 or 5:1 for mining). Then select a chain whose minimum breaking load exceeds that value. Most reputable mining chain manufacturers provide a load chart – use it.

Do not oversize unnecessarily: a chain that is too heavy can increase energy consumption and wear on sprockets and drive units.

Step 3: Material and Heat Treatment – The Heart of Chain Quality

The base material for high-grade mining chains is usually alloy steel with a specific composition, such as:

• 23MnNiMoCr54 (European standard) – excellent hardenability and toughness

• 20Mn2 (common for lower grades)

• 25MnV or similar for specific national standards

Raw material alone is not enough. The chain must go through controlled heat treatment:

1. Quenching – to achieve high surface hardness (wear resistance)

2. Tempering – to balance hardness with core toughness (impact resistance)

Step 4: Certification and Traceability – Non‑negotiable for Mining

A mining chain without proper certification is a liability. For most mines, you will need:

• ISO 9001 (manufacturing quality system)

• Specific product standards: DIN 22252, DIN 22255, ISO 1835, etc.

• Third-party certification: For anchor chains, ABS, DNV, LR, CCS. For mining chains, often MA (China mining approval) or equivalent local authority.

• Traceability: Each chain batch must have a unique heat number, and test certificates must include chemical analysis, tensile test, and proof load test results.

Never accept a “generic” chain without documentation. If a chain fails underground, traceability can determine liability and prevent repeat failures.

Step 5: Consider the Complete Rigging System

A mining chain does not work alone. It is attached to connectors, shackles, master links, and sprockets. These components must have the same or higher working load limit (WLL) as the chain.

Critical checks:

• Inner width of the chain must match the sprocket or flight bar dimensions.

• Connecting links (C-links, semi-links) must be of the same grade and properly heat-treated – many failures happen at connectors.

• Shackles – use only bow or screw pin shackles rated for the same WLL.

For a complete haulage or conveyor system, buy all rigging components from a single reliable supplier who can guarantee compatibility.

Step 6: Plan for Inspection and Replacement

Mining chains are wear items. They stretch, corrode, and fatigue over time. Set up a preventive maintenance schedule:

• Measure chain elongation regularly. When elongation exceeds 3% to 5% (depending on the standard), replace the chain.

• Check for cracks using magnetic particle inspection (MPI) or dye penetrant testing – especially at the weld zone of each link.

• Inspect for gouges, necking, or significant corrosion. Any of these reduces the effective cross-section and lowers breaking strength.

Proactive replacement is always cheaper than a catastrophic failure at 2 AM.

Your next step:
Share your mine’s conveyor or haulage specifications with us. We will recommend the exact chain grade, size, and rigging package – complete with test certificates and traceability.

[Contact our mining chain specialists today]