Mining Cable Support Hooks and Clamps

pH 3.4–4.3, 3.5 years, −31~39% and −11.7% are measured values on X-grade rock bolts from Australian coal mines (Aziz et al. 2014, traced); "same order of magnitude for hooks" is a magnitude estimate extended from the same mine-water medium, with no same-source measurement on hooks or clamps; the SCC row is an extension to high-strength steel fasteners.

1. 1Mine water is acidic sulfate, measured at pH 3.4–4.3 — hooks sit in a corrosive medium below pH 5 for their whole service life
2. 2Loss is uniform: the same environment measured about 11.7% diameter loss over 3.5 years, and the smaller the section, the faster the reserve disappears (magnitude estimate)
3. 3Tensile strength drops 31–39% over the same period — the cable load stays constant, so the stress ratio climbs year by year
4. 4Underground fixings have no routine-recheck culture (bolts go into the roof for life); with hook checks scheduled by the year, fracture gives almost no early warning
5. 5One broken hook drops the cable to the floor — a contact hazard for plant and people — and a slow variable ends in a roadway-level outage or injury

pH, −31~39% and −11.7% are measured on X-grade rock bolts (traced) and extended to hooks; "smaller section loses reserve faster" is general section logic, not measured; step 5 is a qualitative consequence of the scenario (cable fall, outage, contact hazard), with no figures.

• Certification gate (China): the MA mine-safety mark is a one-vote veto — products on the catalog cannot be made or sold without it and mines cannot buy them; check before ordering whether hooks, clamps or anchor bolts are on the MA catalog and whether certification applies (a catalog item already confirmed: resin bolt cartridges)
• Documentation is part of the delivery (US practice): MSHA has mines request manufacturer certification for roof bolts and accessories — ship the certification and material certificates with the batch as part of the order
• Acceptance is the final inspection: sampling of underground fixings happens on the installation shift, with no after-sales recheck stage — the dispute window is very short, so batch-to-batch consistency matters more than unit price
• Select material for the whole service life: support is designed as "not touched for ten years", and the corrosion rate sets the real upper life limit — spec hook material and coating against the full roadway life, not against piece price

The MA scheme and the resin-cartridge catalog example come from the MA national center (medium-high confidence); the MSHA manufacturer-certification practice comes from 30 CFR §56.3203 / §57.3203 (traced); "not touched for ten years" follows the KB's statement of support-design intent. No bolt-specific torque/tension figures (the 50% rule, 150 ft-lb, etc.) are used here — those belong to sibling pages.

In scope (fastener-class hardware): cable hooks, cable clamps and fixing clamps with their anchor bolts (expansion/anchor type), plus ground-support fittings from the same roadway — rock bolt nuts with plates (including spherical seat washers), W-strap connection bolts, cable bolt locks (wedges/anchor bodies) and mesh tie wire. Out of scope (dedicated lines and chemicals): bolt and cable bodies (left-hand rebar and prestressing strand on dedicated production lines), resin cartridges (chemicals), and roof bolter machines. Quote against this boundary so dedicated bolt bodies are not asked for as ordinary fasteners. Cable-hanging hardware itself is not on the profile's in-scope list; whether it joins this product line is for the merge review to decide.

The in-scope/out-of-scope lists are drawn from the boundary row of KB §5 (traced); cable-hanging hardware itself is not in that in-scope column — a draft-stage gap, left for the merge review to decide whether the supply line extends to hanging hardware.