Mining and Minerals: Reliable Silo and Crusher Monitoring

Technical guide by Arvin, METRAVON Instruments · Reviewed September 2026

Short answer

Mining level measurement should be designed around the operating decision, not around a single instrument. Use continuous level for inventory trend and process visibility, independent point-level or flow detection where a blocked chute or overfilled bin can stop production, and weighing where the required result is mass rather than surface position. Dust-resistant measurement does not remove the need for impact protection, safe access or a realistic commissioning test.

Ore size, fines content, moisture, angle of repose and filling method can change from one campaign to the next. Confirm the full operating envelope and test the measurement while material is moving, because a quiet empty bin is rarely the most demanding condition.

Start with the process consequence

Understand the material and vessel

Record the largest lump size, fines fraction, bulk-density range, moisture, stickiness, temperature and expected buildup. Include bin height and diameter, hopper geometry, liners, roof members, feed trajectory, discharge arrangement and normal surface profile. In a crusher or transfer station, also document vibration, shock, water sprays and maintenance access.

Coarse ore creates an irregular, rapidly changing surface. Aerated fines may behave differently after settling. Wet ore can adhere to walls or form bridges. These effects influence the relationship between a measured distance, usable volume and actual mass; they should be treated as known uncertainty rather than hidden by excessive signal damping.

Continuous non-contact measurement

Non-contact radar is commonly evaluated for tall ore bins and silos because no probe hangs in the material. Select the mounting point from the complete beam path. Keep it away from direct impact, dense filling streams and structural obstructions, and ensure that any guard or deflector does not block the measurement.

A narrow beam can help in confined geometry, but frequency alone does not establish suitability. Review range, antenna, nozzle, dust, temperature, condensation, buildup, hazardous-area requirements and the model-specific data sheet. Save echo information during commissioning so later changes can be compared with an accepted baseline.

Impact, abrasion and mechanical protection

The instrument should not be used as a structural impact target. Position it outside the predicted trajectory of falling rock and rebound. If a protective structure is required, check it for material accumulation, maintenance access and interference with the sensing path. Inspect the mounting flange, fasteners, cable support and enclosure after vibration and impact events.

Mechanical protection must be designed by the responsible plant discipline. A website description cannot determine the load from large rocks, a failed liner or a moving chute. Keep personnel away from unsupported material and follow the site's isolation and confined-space procedures.

High-level, blockage and empty protection

Calculate high-high alarm position from maximum inflow, conveyor speed and length, stopping delay and remaining safe capacity. An alarm that is set at the nominal full level may arrive too late because material already on the belt will continue entering the bin.

For blockage detection, first define the failure: no material flow, a full chute, a stalled crusher or an empty feeder. A point switch can indicate material at its location, but it may need to be combined with belt motion, motor load, feeder status or another suitable flow signal. Critical trips should be reviewed for independence from the continuous inventory measurement.

Inventory and remote data

Level-to-tonnage conversion requires a vessel volume table and representative bulk density. Keep separate density values for materially different ores or moisture ranges, and preserve the original level value. Remote dashboards should show instrument status, last update time, signal quality and communication state so that stale data is not mistaken for a stable inventory.

Local protection must continue when a network or cloud connection is unavailable. Define buffering, timestamping and retransmission rules for remote sites, and use stable equipment identifiers across PLC, gateway and reporting systems.

Commissioning and acceptance

1. Verify bin identity, drawings, material range, mounting, cable protection, outputs and alarm cause-and-effect.
2. Check an empty or known reference and record fixed echoes from liners, braces and chutes.
3. Observe filling and discharge at normal and high rates, including the dustiest practical condition.
4. Test high-high, low, blockage, device-fault, power-loss and communication-loss responses through the complete control loop.
5. Compare inventory estimates with an agreed reference across several operating cycles rather than one point.
6. Handover parameters, echo records, alarm settings, drawings, test results and safe maintenance instructions.

Information required for selection

Provide the ore or mineral name, lump-size distribution, fines, moisture, bulk density and temperature; vessel and liner drawings; filling and discharge paths; range and required accuracy; dust, vibration, impact and hazardous-area conditions; alarm consequences and stopping time; power, output and communication requirements; and photographs of the proposed mounting area.

Frequently asked questions

Can radar measure large, uneven ore surfaces?

It can be evaluated, but the mounting position, range, beam path and changing surface must be reviewed. Acceptance should include actual filling and discharge conditions.

Why does calculated tonnage disagree with dispatch records?

Check the vessel volume table, bulk density, wall buildup, surface model and timing of both records. The radar distance may be correct while the mass conversion is not.

Should a high-level alarm use the continuous level signal?

It may provide an operating alarm. Where overflow has a serious consequence, assess an independent sensor and signal path to reduce common-cause failure.

How often should the installation be inspected?

Set the interval from observed buildup, vibration, fastener condition, signal trend and process risk. Inspect after significant impact, liner work or abnormal readings.

Characterize the ore and operating envelope

Record top size, fines, moisture, bulk density, angle of repose, abrasiveness and tendency to bridge. Include normal and upset feed rates, drop height, temperature and water sprays. Mine material changes by bench, season and processing stage; select against the credible range rather than one laboratory sample. Large rock and fine dust can occur in the same location at different times.

Define the required result: high-level protection, continuous trend, available surge capacity, crusher choke control or mass inventory. These functions have different response and accuracy needs. A radar measurement of an uneven surface is not direct tonnage, while a point switch cannot show the rate at which the surge bin is filling.

Protect the measurement without creating a blind zone

Keep radar and switches outside the direct trajectory of falling rock. Structural guards may be necessary, but they must not block the beam, trap material or become a false target. Locate cable and housing protection beyond impact and washdown paths. Check that vibration cannot loosen the mount or change antenna alignment.

For abrasive service, minimize exposed contact parts and inspect process connections for erosion. If air purge is used, confirm pressure, quality and availability and avoid blowing dust into an unsafe area. Provide access that does not require personnel to stand below stored material or enter a confined space.

Crusher and conveyor interlocks

Combine bin level with feeder state, belt speed, motor current and crusher status. Rising level with a running downstream conveyor may indicate restricted flow; unchanged level with a stopped belt may reveal a blocked sensor or bridge. Define timers from actual transport delay so one device stopping does not continue feeding an unsafe accumulation.

Use a sequence-of-events record with synchronized time. Test stop and restart order, emergency conditions and loss of communication. Local protection must continue if a remote monitoring link fails. Clearly distinguish an invalid sensor from a genuine empty or full state in the control logic.

Commissioning under dynamic conditions

Record empty echoes and fixed obstacles before production. Observe the radar during normal feed, maximum dust and asymmetric discharge. Compare readings at several safe reference conditions. Test point alarms with material where possible and verify the final feeder or conveyor action, not only the local relay.

Conduct controlled tests for blocked flow, stopped belt, sensor fault and power loss. Confirm alarm priority and operator response. Save echo curves, parameters and individual test evidence. A static empty-bin check cannot demonstrate performance during impact, vibration and dust.

Maintenance based on degradation

Trend echo margin, alarm frequency, mounting movement, cable damage and buildup. Inspect after abnormal impact, roof work or process changes. Avoid adjusting sensitivity each time conditions worsen; compare against the baseline and correct mechanical causes first. Repeated guard damage or antenna coating indicates that location or protection needs redesign.

Plan isolation, lockout, fall protection and confined-space controls before maintenance. Define spares for critical devices and keep approved configuration files. Following replacement, verify orientation, scale, fault state and the complete interlock. Document as-found condition so reliability improvements are based on evidence.

Engineering note: Structural impact protection, hazardous-area suitability and safety interlocks must be approved for the actual mine, equipment and jurisdiction using model-specific documentation.