What this sector has to measure
Mining is the sector where the instrument has to survive the process before it can measure it. Abrasive slurry, coarse solids, heavy vibration, dust and a wide ambient temperature swing are normal operating conditions rather than exceptional ones, and an instrument that would be perfectly adequate elsewhere in a process plant can be destroyed within a season by the same duty here.
That pushes the specification towards obstructionless designs and towards measurement from outside the pipe or the vessel. An electromagnetic meter with a wear-resistant liner replaces anything with a moving part; a non-contact level measurement replaces a float that the material would bury; a transmitter with a large flush diaphragm replaces one with a small port that would block. The engineering effort goes into the interface with the medium rather than into the electronics.
The measurements themselves are frequently about mass balance rather than about a precise figure. How much ore came in, how much concentrate went out, how much water is being added and how much is going to tailings - those numbers decide whether the plant is doing what it was designed to do, and they are compared with each other rather than judged individually. That is why density and flow are often measured together, and why wear resistance and drift stability matter more here than absolute accuracy.
Where the instruments sit
Extraction and haulage
Drilling, blasting, loading and conveying. Instrumentation here is mostly about condition and safety - vibration on crushers and conveyors, belt and chute detection, and gas or dust monitoring in enclosed spaces.
Comminution
Crushing and grinding circuits, where feed rate, water addition, power draw and slurry density are controlled together. The measurements are closely coupled, and the circulating load is controlled from them rather than from a single reading.
Separation and thickening
Flotation cells, cyclones, thickeners and filters. Level, density, flow and interface detection dominate, and the media are abrasive and frequently frothy.
Tailings, water and services
Tailings transport and storage, process water and site services. Flow and level measurements here carry a containment obligation, so reliability matters at least as much as accuracy.
Instrumentation used in this sector
| Measurement | What is measured in this sector | Instruments commonly specified |
| Flow | Slurry in grinding and flotation circuits, process water, reagent dosing and tailings transport | Electromagnetic meters with wear-resistant liners, ultrasonic meters where the pipe cannot be opened, and positive-displacement or mass measurement for reagents |
| Density and interface | Slurry density in the grinding circuit, underflow density at the thickener, and the bed level in the thickener itself | Radiometric density measurement, mass flow measurement where density is derived from it, and interface instruments for the thickener bed |
| Level | Crusher bins, ore stockpiles, sumps, thickeners and process tanks | Radar and ultrasonic transmitters chosen for the dust and the surface condition, hydrostatic transmitters where the medium permits, and switches that tolerate being buried or coated |
| Pressure | Slurry pumping, cyclone feed, filter presses and the water circuit | Transmitters with a flush or large diaphragm to avoid blocking, and seals where the medium would attack the element |
| Vibration and condition | Crushers, screens, conveyors, pumps and drives | Accelerometer or velocity measurement, often on a route-based inspection rather than permanently installed |
| Gas and dust | Confined spaces, reagent storage, and dust at enclosed transfer points | Portable gas detectors for entry, fixed detection where a hazard is present continuously, and dust measurement where an exposure limit applies |
Wear is a design requirement in this sector rather than a maintenance item. Where the medium is abrasive, the liner, the diaphragm and the mounting frequently decide how long the measurement lasts.
How to specify for a mining operation
- Abrasion first. Slurry is the defining difficulty, so the liner, the diaphragm and the mounting are chosen for wear before accuracy is discussed, and a wear-resistant instrument of modest accuracy normally outlasts a precise one without it.
- Whether the medium can be measured from outside. Where the pipe or vessel is difficult to open and the process cannot be interrupted, non-contact or clamp-on measurement is preferred even at some cost in accuracy.
- Solids size and settling behaviour, since coarse solids settle quickly, block small ports and produce a velocity profile in the pipe that affects the reading.
- Density as a measurement in its own right. In grinding and thickening circuits density frequently matters as much as flow, and the two are usually related to each other rather than read independently.
- The environment: dust, vibration, ambient temperature swing and high-pressure washdown, all of which affect the enclosure more than they affect the sensor.
- Power and communications at remote points, which is frequently the reason a measurement is installed with local logging rather than a permanent connection.
- Reagent handling, where the dosing quantity matters, the medium may be hazardous and the materials of construction have to suit it.
- Containment obligations on tailings and process water, where a leak or an undetected overflow carries consequences beyond the plant boundary.
Standards and approvals that may apply
- Hazardous-area certification schemes where reagents or hydrocarbons are handled, which the installation may be required to carry.
- Dust and gas exposure obligations, which fix the monitoring method and the record rather than the instrument.
- Environmental containment and discharge requirements for tailings and process water, where a measured value may be reported to an authority.
- Machinery condition and guarding standards applied by the site to rotating equipment and conveyors.
- We describe what an installation may have to meet. We do not claim that any approval is held for a product unless the certificate has been supplied to us, and the product pages follow the same rule.
Applications in this sector
