The "Ex" logo trap

A device that is safe and legal in a European warehouse can be illegal on a South African mine. Here is why, and the one thing to check before you buy.

Here is a scenario that plays out more often than the industry likes to admit. A newer supplier or vendor takes on a personnel tracking job at a mine. They source a capable tag, it carries an "Ex" marking and a foreign certificate, and everyone assumes the compliance box is ticked. Months later, during an audit or an incident investigation, someone asks the one question that matters: is this device actually certified for use in this mine? Too often the answer is no.

These tags are the wearable end of a missing person locator system, the capability Regulation 16.7 of the Mine Health and Safety Act requires. They go on people who go underground, which places them squarely inside the mine's explosion protection regime, and the rules there are specific. This article explains what intrinsic safety certification really means, which certification applies underground versus on surface, and the exact thing to check before you buy.

What intrinsic safety actually is

Intrinsic safety, marked "Ex i", is a protection method that limits the electrical and thermal energy a device can release, so it cannot ignite a flammable atmosphere even in a fault condition. It is the protection type most relevant to small, battery powered devices such as tags, sensors and cap lamps, and it sits within the SANS 60079 series of standards, with intrinsic safety covered specifically by SANS 60079-11. For the highest risk zones you need the highest level, Ex ia; a lower level, Ex ib, applies to less frequently hazardous zones. For equipment carried in a fiery mine this typically means a Group I device at the highest intrinsic safety level, marked for Group I as Ex ia I, whereas a surface gas device is marked for Group II, for example Ex ia IIC. The full marking, not a general assurance, is what tells you what a device is actually cleared for.

The key point for buyers: "Ex i" is not one universal stamp. A certificate is only meaningful for the specific gas group, protection level and environment it was issued for.

The distinction that trips people up: group, and underground versus surface

Explosion protected equipment is classified by the kind of atmosphere it is certified for:

• Group I covers mines endangered by firedamp, meaning methane. This is the mining group.
• Group II covers surface industries with flammable gas or vapour.
• Group III covers surface combustible dust.

A device certified only for Group II surface use is not valid in a fiery Group I environment, no matter how genuine its certificate is. This is the single most common misunderstanding.

There is a South African wrinkle that catches even experienced buyers. Hard rock mines, such as gold and platinum group metals, are normally not classified as fiery, so it is tempting to assume the intrinsic safety question falls away. It does not. The regulator is explicit about it: the Chief Inspector of Mines issued a guideline for a mandatory code of practice for the prevention of flammable gas explosions in mines other than coal mines (Government Gazette No. 44427, 9 April 2021), which treats the flammable gas instrument a miner carries as an intrinsically safe device and requires ignition sources, electrical equipment among them, to be controlled. Flammable gas, and the need for explosion protection, is a recognised hazard well beyond coal. Look at what already goes onto a miner. The cap lamp standard, SANS 1438, normatively references the SANS 60079 series, including SANS 60079-11 for intrinsic safety, and its marking clause requires every light assembly to comply with ARP 0108 and carry an Ex ia I/IIC T4 rating. The portable gas instrument a miner carries tells the same story: instruments certified to SANS 1515-1, the standard for battery operated portable flammable gas measuring instruments, are certified together with the SANS 60079 intrinsic safety series, and the ones used underground carry a Group I rating in the form Ex ia I Ma, issued locally by an ATL such as MASC.

Neither standard is written about tracking devices, but together they establish a clear principle: the things a miner carries underground are expected to hold a SANS 60079 intrinsic safety certification, issued locally. The reasonable conclusion, and the position we take, is that a tracking tag worn by a person going underground should meet at least that same standard. In practice, "it is only a small tag" is not a defence.

It is worth being honest about a gap here: MHSA Regulation 16.7, which requires the missing person locator system, does not itself spell out which intrinsic safety certification is required. That silence is part of why the market gets it wrong. The requirement comes from the mine's own hazardous area classification, carried out under SANS 10108, the standard for classifying hazardous locations and selecting apparatus for them, and it is reinforced by the standards for specific carried equipment, such as SANS 1438 for cap lamps. It does not come from 16.7 itself.

The protection level a locator needs: Ma, not just any Ex ia

Group is one axis; the equipment protection level is another, and for a missing person locator it is where the specification gets specific. Group I intrinsic safety comes at two levels. SANS 60079-0 defines EPL Ma as a very high level of protection that stays safe even when a device is left energised during an outbreak of gas, and EPL Mb as a high level that is safe only in the span between a gas outbreak and the device being switched off. Read that against what a locator is for. A device marked Ex ib I Mb is one the scheme expects to be isolated when gas appears, which is the exact moment you most need a missing person to still be visible. The level that keeps a wearable working through an incident is Ex ia I Ma. This is not a detail to leave to a datasheet: it follows straight from Regulation 16.7's requirement to locate a person during and after a shift.

The part almost everyone gets wrong: a foreign mark is not enough

This is the crux. A device carrying an IECEx or ATEX certificate is not, on its own, certified for use in a South African mine. It must be certified locally, through an Approved Testing Laboratory (ATL), under the Department of Mineral and Petroleum Resources (DMPR) guideline ARP 0108. In the South African scheme, Group I mining equipment is approved on the authority of the chief inspector of mines, and Group II surface equipment on that of the chief inspector of factories, which is a further reason a foreign certificate on its own does not settle the question.

It helps to see the two South African instruments as a pair that work together. SANS 10108 is the engineering standard: it classifies a site's hazardous zones and sets the equipment protection level each zone needs. ARP 0108 is the regulatory framework: it governs how an ATL issues the Inspection Authority (IA) certificate that proves a device actually meets those requirements. The mine classifies the zone under the one and demands proof of certification under the other, so a device is only truly cleared when the classification and a local IA certificate line up.

The practical proof is a certificate from a recognised ATL, and the certificate number that goes with it. In South Africa, MASC, Mining And Surface Certification (Pty) Ltd (masc-ex.com), is one such Approved Testing Laboratory, and it certifies equipment for both underground mine and surface use. It is not the only ATL in the country, but it is the laboratory Ideas2Impact works with and trusts. A compliant device shows an ATL certificate and number, not merely a foreign Ex logo or a certificate from another jurisdiction. If a tag cannot show that, treat it as uncertified for your mine until proven otherwise, whatever other marks it wears.

Why this is a real risk, not a technicality

Two things make this dangerous rather than academic.

First, the duty sits with the mine. Under the Mine Health and Safety Act the employer carries the obligation to ensure equipment used underground is safe and lawful. If a supplier or vendor provides a device that is not properly certified, it is ultimately the mine that is exposed, both to an inspector and, far more seriously, to the consequences of an ignition.

Second, the people making the buying decision are often not equipped to catch it. Newer suppliers and vendors may not know that a foreign mark is insufficient, and mines are frequently not clued up on which certification their classification actually requires. The result is uncertified devices being sold and installed in good faith, sitting quietly in service until the day they are scrutinised.

What to demand before you buy

A short checklist that turns all of the above into questions you can ask a supplier:

• Show me the ATL certificate and its number for this exact device, and which laboratory issued it (for example MASC).
• Which group is it certified for, and does that match our mine's classification, Group I for anything carried underground in a fiery or lamp regime?
• What is the full Ex marking? For anything carried underground it should name Group I at the right protection level, Ex ia I (for reference, SANS 1438 requires cap lamps to carry an Ex ia I/IIC T4 rating); a surface device names Group II, for example Ex ia IIC.
• If it is worn or mounted a particular way, for example clipped to a cap lamp, is that configuration covered by the certificate?
• Provide the Approved Testing Laboratory certificate, not just a photograph of a marking.

If a supplier cannot answer these quickly and in writing, that is your answer.

How Ideas2Impact helps

Ideas2Impact comes at missing person locator systems from a safety systems background, so certification is where we start, not an afterthought. We help mines and their suppliers and vendors check that what goes underground is genuinely certified for their classification, and we design tracking systems around that reality rather than around whatever tag happens to be cheapest. We are transparent about status too: where a device is still completing local certification, we say so, rather than letting an "Ex" logo do the talking.

This article is general information and does not constitute legal, compliance or certification advice. Confirm the applicable standards, your mine's hazardous area classification, and the certification status of any device against the official standards, the DMPR, and your appointed advisors.