Mining.

Specify the rod around the working mill.

JOTAIN supplies finished, heat-treated grinding rods in 42CrMoA, 40Cr, 65Mn and 50#. The published family diameter range is Ø60–160 mm. Grade, delivery condition and dimensions are confirmed per order; this does not imply that every grade is available in every family size. Straightening, fixed-length cutting, inspection, marking and export packing are reviewed against the actual rod-mill duty.

Supply

Heat-treated, straightened rods cut to the ordered length, with agreed end condition, identification and packing. Confirm diameter, tolerance, usable length and the mill’s handling limits.

Hardness

Agree the target band, scale and test method, surface and internal test positions where specified, sampling and heat-treatment lot uniformity. Hardness alone does not establish service life.

Mill duty

Provide feed characteristics, mill size and operating conditions, current rod material and size, consumption in kg/t, and any breakage, bending, spalling or tangling history.

Acceptance

Confirm straightness measurement and sampling, flat crack-free ends, surface condition, inspection records and trial quantity. Compare trials over matched operating conditions before assessing repeatability.

Review the core at the controlling section.

Shaft and pin blanks for heavy rotating and articulated machinery are supplied through the agreed bar or forging route. Diameter, heat-treatment response, cyclic load and impact duty determine the property review; the critical section must be represented by the agreed test location.

Supply

QT bar, peeled stock or rough-machined blanks with drawing-defined allowance.

Section

Confirm ruling diameter, core toughness, hardness profile, test position and the OEM property targets.

Inspection

Agree internal soundness, UT when specified, surface acceptance, straightness, end condition and dimensional reports.

Control the thread-root fatigue zone.

Heat-treated alloy bar and prepared threaded material are reviewed for high-load machinery ties and fasteners. Material properties, preload, engagement and the thread-manufacturing route must suit the purchaser’s peak and cyclic loading requirements.

Supply

Heat-treated bar and thread-ready preparation or agreed end machining, with specified mechanical acceptance.

Interfaces

Thread standard and class, engagement, preload, thread roots, transition geometry and surface condition.

Next stage

Straightness, end condition, machining allowance, surface acceptance and UT where specified.

Check internal quality before finish machining.

Rough-machined heavy parts are prepared through a rolled or forged material route with agreed machining allowance. The OEM drawing defines the critical section, heat-treatment responsibility, datums and inspection stages before final machining.

Supply

Rolled or forged stock, rough machining and a drawing-specific dimensional report.

Before cutting

Resolve UT stage and acceptance, internal soundness and the heat-treatment condition at the critical section.

Allowance

Confirm datums, stock allowance, straightness and surface condition for the next machining or assembly operation.

Match a solid tendon to the excavation sequence.

Solid FRP rock bolts provide a cuttable rod route for face reinforcement and ground support where later excavation is planned. The solid GFRP tendon is installed in a pre-drilled hole with the project-specified grout or resin system.

Rod

Confirm solid cross-section, profile, diameter, length and required tensile and head-assembly properties.

Installation

Agree hole geometry, grout or resin compatibility, cure requirements and installation equipment.

Mating parts

Match plate and nut material to the required cuttability, bearing surface and project acceptance.

Use the hollow core for the agreed grouting route.

Hollow FRP rock bolts combine a cuttable GFRP tendon with an internal passage for grout. This product route uses a pre-drilled hole; self-drilling bolts are reviewed separately for their drilling and connection requirements.

Rod

Confirm outer and inner diameters, length, profile and the required rod and head-assembly acceptance.

Grouting

Agree grout compatibility, injection connection, sealing and the specified installation procedure.

Mating parts

Confirm plate, nut and any extension interface, including the required cuttability and bearing arrangement.

Coordinate the bar, drill bit and grout path.

A self-drilling hollow rock-bolt route combines a threaded hollow bar, drill bit and grout passage. The ground conditions and installation equipment govern selection, including where a pre-drilled hole cannot remain open for conventional insertion.

Bar

Confirm the specified steel or FRP route, outer and inner diameters, thread form and section lengths.

Interfaces

Review drill-bit type, coupling engagement, injection connection, bearing plate and nut against the installation method.

Acceptance

Specify ground conditions, grout procedure, required support properties, protection and installation or pull-test records.

Match expansion to the borehole and ground.

Expandable friction bolts use a formed steel tube that expands against the borehole wall when installed with high-pressure water. This route is reviewed for roof and wall support with hole dimensions, installation equipment and ground conditions specified together.

Tube

Confirm profile, finished length, end fittings, corrosion protection and the required acceptance.

Installation

Agree hole size and condition, expansion equipment and the supplier-approved installation procedure.

Verification

Specify installation records, inspection and project-required pull testing. Capacity is confirmed for the selected product and ground conditions.

Specify the complete anchorage arrangement.

Combination rock bolts are reviewed as steel or FRP product configurations against the excavation sequence. Specify the intended initial anchorage and subsequent bonding or grouting arrangement, together with cuttability and protection requirements where applicable.

Configuration

State the selected steel or FRP route, rod, sleeve or pipe, anchorage head and any grout passage. These are alternative configurations, not an assumed steel–FRP hybrid.

Sequence

Confirm immediate-support requirements, later grouting, temporary or permanent duty and the approved installation method.

Interfaces

Review plate, nut, connection fit, corrosion protection and project-required system verification.

Review the rod and expansion head together.

Mechanical rock-bolt assemblies combine a load-bearing rod with a matched expansion head. The accepted drawing and ground conditions govern the rod, head geometry, hole size and installation requirements.

Assembly

Confirm rod material and profile, expansion shell and cone, head connection, bearing plate and nut.

Installation

Specify borehole diameter and straightness, rock condition, tensioning method and the approved setting procedure.

Verification

Confirm engagement, installed load or testing requirements, corrosion protection and any subsequent grouting. Product ratings and installation acceptance are agreed for the selected assembly.

Confirm the head and its mating hardware.

Bail-type mechanical anchors are reviewed with the specified rod and mating hardware. The setting arrangement, hole geometry and ground conditions control selection; the supplied head configuration must match the approved installation procedure.

Head

Confirm shell or wedge configuration, rod diameter, thread connection and the required load basis.

Hardware

Match the bearing plate, nut and washer arrangement to the head and rod.

Installation

Confirm the setting and tensioning method, grout-tube arrangement if specified, and project-required inspection or pull testing.

Match the frame to the excavation geometry.

Lattice girders are three-dimensional steel frames for tunnel and heading support. Main bars, secondary bars, stiffeners and connection details are reviewed against the purchaser’s support design and excavation profile.

Geometry

Confirm radius, frame section, segment lengths, spacing and erection tolerance.

Connections

Specify connection plates, footplates, joints and the interface with the surrounding support or lining.

Supply

Agree material, fabrication and weld requirements, dimensional checks, marking and delivery sequence.

Coordinate the canopy and installation sequence.

Umbrella or forepoling pipes form an advance support canopy ahead of a tunnel or heading. Pipe sections, joints and installation geometry are reviewed for the specified ground conditions and excavation sequence.

Pipes

Confirm diameter, wall thickness, section length, steel specification and connection details.

Layout

Specify installation angle, pipe spacing, overlap, canopy length and drilling equipment interfaces.

Acceptance

Agree joint fit, straightness, grouting details where specified, corrosion protection and inspection records.