Conveyor belt splicing: hot vulcanised, cold bonded or mechanical, and what the crew needs on a mine

A conveyor belt splice is the joint that makes a belt endless or repairs a cut belt. A hot vulcanised splice bonds the prepared ends under heat and pressure in a press. A cold bonded splice joins them with an adhesive that cures at ambient temperature. A mechanical splice clamps them with metal fasteners.^[4][5]

The ends of a textile belt are cut in steps, one ply at a time, or into interlocking fingers. The joint then spreads the load over a long overlap. A belt maker's splicing service lists stepped bias splices and finger splices for textile-reinforced belts. The service lists a separate method for steel cord belts.^[6][4]

For South African mines, the Chief Inspector of Mines' 2014 guideline on conveyor belt installations lists two documents among its references. One is a British code of practice for on-site non-mechanical jointing of textile and steel belting (BS 6593:1985). The other is a German test method for conveyor belt splices (DIN 22110-3, September 1993).^[1]

In practice, makers and repairers rank the three methods the same way. Hot vulcanising is the strongest and longest-lasting joint. Cold bonding suits small belts and plied fabric belts. Mechanical fasteners are the quickest and weakest.^[4][5]

Sources:^[4][5]

A hot vulcanised splice takes from a few hours on a small belt to about a day on a large one. In September 2025 a splicing materials maker's conveyor expert told Dry Cargo International that smaller connections take around four hours. Larger ones take around a day. The expert added that splicing takes two shifts on average. One shift is for surface preparation and one for assembly and vulcanising.^[4]

The stop also includes cutting out the old splice, pulling the belt in and clamping it. Setting up the press and letting the joint cool come before tension goes back on. The 2014 mine conveyor guideline lists cutting, joining, clamping and pulling in a belt as steps the mine's code of practice must cover safely.^[1][4]

One belt maker's splicing service records time, pressure and temperature during each vulcanisation. The buyer gets a record to check against the belt maker's splicing instructions.^[6]

A mechanical splice is acceptable as a quick repair that keeps a fabric belt running until a vulcanised splice can be planned into a stop. The splicing materials maker's expert interviewed in 2025 called mechanical joining only suitable as a temporary solution.^[4]

A conveyor company president writing in Dry Cargo International in May 2020 said a mechanical splice is weaker than the rest of the belt. The fasteners cut or tear the fabric. A vulcanised splice is nearly as strong as the original belt.^[5]

In practice, check the fastener maker's rating against the belt's rated tension and the pulley diameters before accepting a mechanical splice on a main-line belt. Plan its replacement.^[5][4]

The Chief Inspector of Mines' 2014 conveyor guideline lists separate South African standards for general-purpose textile belting, steel cord belting and fire-retardant belting. The fire-retardant standard is for fiery mines. The guideline names SABS 1173:1977 for general purpose textile-reinforced belting and SABS 1366:1982 for steel-cord reinforced belting. For fire-retardant textile-reinforced belting for use in fiery mines, the guideline names SANS 971-2003, edition 3.^[1]

The guideline says the mine's code of practice should describe the design and selection criteria for the belt to prevent fires. The guideline adds that SANS 971-2003 may be referenced for guidance.^[1]

The SABS issued SANS 968:2011 for solid woven textile-reinforced belting on conveyors with flat or troughed idlers. The standard was gazetted on 29 April 2011 (Government Notice 369). Ask the belt supplier for the standard and edition the replacement belt meets, since a splice must match the belt it joins.^[2]

On a mine, a splicing crew works under the mine's own code of practice for conveyor belt installations. Section 9(2) and (3) of the Mine Health and Safety Act, 1996 require the employer to prepare and implement a code of practice. The duty applies when the Chief Inspector of Mines requires it, in line with the Chief Inspector's guidelines. Failing to do so for conveyors breaches the Act.^[1]

The guideline (Government Notice R. 1024, Government Gazette 38339, 19 December 2014) requires that code of practice to schedule maintenance and inspections. The schedule is set against the risks of poor maintenance, repairs and splicing. The guideline lists items for regular inspection. The items include belt adhesives and mechanical fasteners, belt cleaning chemicals, exposure to toxic liquids or fumes, and the hazardous substances used in maintenance.^[1]

The guideline's minimum performance standards require all areas to be locked out, isolated and tagged before any work on a conveyor. A mine's code must include these standards unless its risk assessment justifies others. The standards also require a check before restart that nobody is on the belt and that guards and safety interlocks are back in place.^[1]

At a plant outside mining, the Driven Machinery Regulations, 2015 apply to the repair and maintenance of driven machinery (regulation 2). The regulations require every driving belt to be guarded unless it is as safe by its position or construction (regulation 3(d)). The contractor duties under the OHS Act apply to the splicing firm.^[3]

Splices are inspected on the schedule in the site's maintenance plan. The mine guideline puts that item first in its maintenance section. A preventive maintenance plan sets that interval by belt duty. The guideline's minimum standards also note that excessive take-up travel can indicate that one or more splices are failing or have failed.^[1]

A splicing quote should list these items separately:^[4][1]

• the method, splice type (step, finger or steel cord pattern) and splice length, to the belt maker's splicing instructions;^[6][4]
• the crew, shifts and the planned stop, including preparation, vulcanising and cooling;^[4]
• the press, clamps and pulling equipment, and who supplies them;^[1][4]
• splicing materials with their batch numbers and expiry dates, and the safety data for the adhesives and solvents;^[1]
• the vulcanising record of time, pressure and temperature, handed over with the splice;^[6]
• the lockout and permit arrangements under the site's procedure.^[1]