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Mining Safety 8 min read Published 16 June 2026

MHSA 16.7: missing person locator systems for underground mines

By Frank Guo · Technology & Product Leadership, addanode

TL;DR — Under the amended Chapter 16 of the Mine Health and Safety Regulations, regulation 16.7 introduces a stand-alone duty: no person should go underground without an intrinsically safe device capable of determining their last known location if they go missing. The amendment was published under Notice 6052 in Government Gazette No. 52388 on 28 March 2025. The point is to close the gap between "paper certainty" (who signed in) and location certainty (where they actually are) — so that in an emergency, rescue teams can narrow the search instead of combing kilometres of workings. Compliance means a person-location system with underground-rated, intrinsically safe tags and readers, reliable coverage through the workings, and a control-room view that shows last-known positions for evacuation and rescue.

What regulation 16.7 requires

Regulation 16.7 addresses a hard question every underground operation faces in an emergency: where, exactly, are our people? The regulation introduces a specific duty — employers must ensure that no person goes underground without an intrinsically safe device capable of determining the last known location of that person should they go missing in the underground workings. This was formalised when Chapter 16 of the Mine Health and Safety Regulations was amended by substitution under Notice 6052, published in Government Gazette No. 52388 on 28 March 2025.

The intent is precise. A traditional lamp-room tag board tells you who went underground — "paper certainty." It does not tell you where they are now. Regulation 16.7 is about location certainty: shrinking the search area when seconds count, coordinating evacuations, and reducing the secondary risk to rescue teams who would otherwise search blind.

The distinction that matters: a sign-in board proves a person is somewhere underground. A person-location system tells you where they were last seen. In a fire, fall of ground or inrush, that difference is measured in lives and in the time and risk a rescue team is exposed to.

"Intrinsically safe" is not optional

Underground coal and certain other workings carry explosive-atmosphere risk, so any electronic device a person carries must be intrinsically safe — designed so it cannot release enough energy to ignite a flammable atmosphere. This rules out consumer devices and forces purpose-built, certified hardware. When evaluating any person-location system, intrinsic-safety certification appropriate to your environment is a gate, not a feature: without it, the device cannot legally or safely go underground.

Reading the duty as a specification Regulation 16.7 is short, and each phrase in it decides something about the system: a device per person rather than an area system, intrinsic-safety certification as a precondition rather than an option, and a last-known-location capability rather than an attendance record. The purpose named in the regulation is the size of the search area. What the duty says What that forces in the engineering No person goes underground without a device A device issued per person, not an area-based or vehicle-mounted system that infers who was present. The device must be intrinsically safe A gate rather than a feature: without certification for your environment it cannot go underground at all, which rules out consumer hardware. It must determine the last known location Not a sign-in board. A board proves somebody is somewhere underground; the duty is about where they were last seen. … should they go missing in the workings The purpose is a smaller search area — coordinating an evacuation, and reducing the secondary risk to a rescue team searching blind. Chapter 16 was amended by substitution in March 2025 The duty is current, and it is written as an assurance obligation on the employer rather than as guidance.
Reading the duty as a specification Each phrase decides something: a device per person, certified, holding a last known location. The duty → What it forces No person goes underground without a device A device issued per person, not an area-based or vehicle-mounted system that infers who was present. The device must be intrinsically safe A gate rather than a feature: without certification for your environment it cannot go underground at all, which rules out consumer hardware. It must determine the last known location Not a sign-in board. A board proves somebody is somewhere underground; the duty is about where they were last seen. … should they go missing in the workings The purpose is a smaller search area — coordinating an evacuation, and reducing the secondary risk to a rescue team searching blind. Chapter 16 was amended by substitution in March 2025 The duty is current, and it is written as an assurance obligation on the employer rather than as guidance.
Regulation 16.7 read phrase by phrase as a specification. Intrinsic-safety certification is a gate, not a feature — and a last known location is a different capability from an attendance record, which is what a tag board already provides.

How person-location systems work underground

  • Personal tags. Each worker carries an intrinsically safe tag — often built into the cap-lamp or a dedicated device — that identifies them to the network.
  • Readers / nodes through the workings. Fixed readers at strategic points (shaft stations, intersections, travelways, working places) record when a tagged person passes, building a picture of last-known location.
  • A communications backbone. Underground networking carries tag reads back to surface — leaky feeder, fibre, mesh or a combination suited to the mine's layout.
  • A control-room view. A surface dashboard shows who is underground and their last-known zones, with the ability to query an individual instantly during an emergency.
  • Records for evacuation and rescue. The system supports headcounts, evacuation tracking and a defensible record for the inspectorate.

Granularity is a design choice: zone-level last-known location satisfies the core duty, while denser reader placement gives tighter resolution in higher-risk areas. Match the coverage to the risk, not to a brochure spec.

Location technologies underground, compared

TechnologyLocation resolutionInfrastructureIntrinsically safe availabilityFit for 16.7
RFID zone readersZone / last reader passedReaders at portals, levels, travelling-way nodesMature — IS tags and readers widely certifiedCore answer — "last known location" at zone level
Wi-Fi / mesh RSSITens of metresAccess points along haulages, backhaulCertified variants exist; power-hungryGood where a data network is already being built
UWBSub-metreDense anchors; precise time-syncGrowing; check certification per devicePrecision beyond 16.7's need — valuable where proximity systems share the tags
BLE beaconsRoom / zoneBattery beacons + readers or phonesAvailable; battery programme foreverAdequate for zone location; weaker as a rescue-grade record
Leaky feeder + tagsZone along the cableExisting leaky-feeder radio backboneEstablished in SA coalPractical retrofit where the feeder already runs
Cap-lamp integrated tagsDepends on reader techLamp-room issue ties tag to person automaticallyCommon — lamp assemblies are IS-certifiedSolves the "who carries which tag" problem

How to choose a compliant system

  1. Confirm intrinsic-safety certification for your specific environment first. Everything else is moot without it.
  2. Check coverage against your workings. Demand evidence the technology gives reliable reads through your geometry — dips, curves, multiple levels — not just in a demo drive.
  3. Plan the comms backbone. Underground networking is the hard part; person location depends on it. Reuse existing infrastructure where you can.
  4. Make the control-room view emergency-ready. In a crisis you need an instant, unambiguous "where was this person last seen" — not a report you export later.
  5. Integrate with your other safety systems. Person location, collision prevention and environmental monitoring on one platform give you a single safety picture and one set of compliance records.
  6. Plan maintenance and tag logistics. Tags, charging, issuing and reader upkeep are an operational discipline — budget for it so the system stays effective and compliant.

This sits within addanode's mining operations optimisation solution: MHSA-aligned person-location alongside collision prevention and occupational-hygiene monitoring on one addaNet platform, so safety, compliance and production data live together. Because we build both the hardware and the software in-house and support it locally, person location can share the same underground backbone and control room as your other safety systems — engineered for real South African underground conditions.

This guide summarises the regulatory framework for orientation; always confirm current requirements, definitions and effective dates against the latest Mine Health and Safety Regulations and your appointed legal and safety advisers.

Frequently asked questions

What does MHSA regulation 16.7 require?

It requires that no person goes underground without an intrinsically safe device capable of determining their last known location if they go missing in the workings. The duty was formalised when Chapter 16 of the Mine Health and Safety Regulations was amended by substitution under Notice 6052, published in Government Gazette No. 52388 on 28 March 2025.

How is this different from a normal lamp-room tag board?

A tag board gives "paper certainty" — it confirms a person is somewhere underground. Regulation 16.7 is about location certainty: knowing where they were last seen. In a fire, fall of ground or inrush, that lets rescue teams narrow the search area instead of combing kilometres of workings, saving time and reducing risk to the rescuers.

Why does the device have to be intrinsically safe?

Many underground environments carry explosive-atmosphere risk, so any device a person carries must be incapable of releasing enough energy to ignite a flammable atmosphere. Intrinsic-safety certification appropriate to your environment is a non-negotiable gate — consumer devices and uncertified hardware cannot legally or safely go underground.

How precise does the location have to be?

The core duty is satisfied by reliable last-known-location at zone level, achieved with readers at strategic points through the workings. Denser reader placement gives tighter resolution where the risk is highest. The right approach is to match coverage granularity to the risk profile of each area rather than over-engineering everywhere.

Can person location share infrastructure with our other safety systems?

Yes, and it should. Running person location, collision prevention and environmental monitoring on one platform and the same underground communications backbone gives you a single safety picture, one control-room view and one set of compliance records — more reliable and more cost-effective than three separate systems.

Working toward 16.7 compliance?

Tell us about your workings and existing underground comms. We'll help you specify an intrinsically safe person-location system with coverage matched to your risk — and a control-room view that's ready when it matters most.

Talk to our Mining Team See the solution →

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