Conflict Minerals in Machined Parts: 3TG, Cobalt and the Forms

A customer sends a spreadsheet with 40 tabs, a revision number, and a request to complete it within two weeks. The part is a machined aluminium housing. Nobody in the shop has ever bought tin, tantalum, tungsten or gold, and the person filling it in is reasonably sure the answer is "none of these apply."

That instinct is often correct — but "often" is not what the form requires. A declaration is worth what its reasoning is worth. This covers what the rules ask, which alloys carry 3TG and cobalt, and how a shop can answer without overstating what it knows.

What the rules actually require

Two regimes matter most, and they place obligations on different parties.

The US SEC rule under Dodd-Frank Section 1502 applies to issuers of securities that manufacture products containing conflict minerals "necessary to the functionality or production" of the product. Those issuers must conduct due diligence and file a disclosure. Suppliers are pulled in through contract, not through the statute.

EU Regulation 2017/821 places obligations on EU importers of tin, tantalum, tungsten and gold ores, concentrates and certain processed metals, above annual volume thresholds. They must carry out due diligence aligned with the OECD guidance. Again, a machine shop is not the regulated party; it is a link that has to supply data.

In both cases the practical question is the same: does your product contain any of these minerals, and if so, where did they come from? The EU regulation covers 3TG only. Cobalt is outside its scope, though it is covered by the Extended Minerals Reporting Template many customers use.

There is no mass threshold that exempts a trace amount. "Necessary to the functionality or production" is the test, not grams per part. A 2 mg gold flash on a contact counts; a carbide insert used to make the part does not, because it is tooling, not a constituent.

Which materials actually contain 3TG

This is where most of the work sits, and where generic answers fall apart.

The table gives a useful shortcut. A 6061-T6 or 7075 aluminium bracket, machined and anodized, contains none of the five. So does a 304 or 316 stainless part, or a 1018 steel part. The moment the drawing moves to bronze, a tungsten tool steel, a cobalt alloy or a gold-plated contact, the question becomes real and the answer needs a smelter.

What matters is the alloy, not the process. Cutting aluminium with cobalt-bearing carbide tools does not introduce cobalt into the part.

See also: Sending CAD Data to a Machine Shop: What to Control and CBAM and Machined Metal Parts: The Supplier View.

Cobalt, and why the EMRT exists

Cobalt sits outside both the SEC rule and the EU regulation, but it has become the fifth mineral in practice because of artisanal mining risk in the Democratic Republic of the Congo. Most large customers now request the Extended Minerals Reporting Template alongside the CMRT, and some contracts make it mandatory.

For machined parts, cobalt is the mineral most likely to be genuinely present, because carbide and wear-resistant alloys are common. A Stellite valve seat is roughly half cobalt by mass, and a brazed carbide insert carries 6-12% cobalt. If your part family includes wear components, expect the EMRT request to be substantive rather than a formality.

Filling in the CMRT without inventing data

The CMRT asks for a company-level declaration, a smelter and refiner list, country of origin, and a description of due diligence. The discipline is choosing the right status.

There are, broadly, three honest positions:

1. No 3TG in the product. Support it with the material specification and alloy chemistry. For aluminium and stainless steel parts, this is defensible and can be answered in an hour.
2. 3TG present, source known. You have mill certificates and declarations naming smelters or refiners, ideally conformant with a recognised assessment programme such as RMAP. This is the strongest answer and requires upstream cooperation.
3. 3TG present, source unknown. This is the most common honest answer for a small shop buying bronze from a distributor. Declare the mineral as present, mark the smelter list as unknown, and describe the reasonable country of origin inquiry you performed.

The third position is not a failure. Customers distinguish between an unknown source disclosed honestly and a false "not present": the first is a gap that can be closed, the second is a misstatement.

A reasonable country of origin inquiry is a documented, good-faith process, not a full audit: a written request to your material supplier for the smelter identity and country of origin, a record of the response or non-response, and a note of what you did when no answer came back. Two emails and a file note are a legitimate RCOI if they are dated and specific.

What to ask your own suppliers

The leverage sits with the mill and the distributor. Ask three questions of whoever supplies the metal:

• Does this grade contain tin, tantalum, tungsten, gold or cobalt, by specification?
• If yes, can you name the smelter or refiner and the country of origin?
• If you cannot name the smelter, what is your own due diligence process, and can you state it in writing?

For cobalt-bearing carbide and tool steel, also ask whether the material is sourced from recycled stock, which changes the origin question substantially. Recycled feedstock is not automatically exempt, but it is a different and often better-documented chain.

Buying through a distributor rather than a mill slows the answers and makes them less specific. Build that into your response time. A customer asking for a completed CMRT in 48 hours is asking for something you may not be able to produce honestly in 48 hours — say so early rather than filling the form with assumptions.

Our materials page lists the grades we stock and the documentation that travels with them, and contact is the right place to ask for a material-specific answer before you complete a declaration.

Frequently asked questions

Does a machined aluminium part need a conflict minerals declaration?

Usually the answer is "no 3TG present", which still has to be documented. Aluminium alloys do not contain tin, tantalum, tungsten or gold as specified elements. Complete the form declaring no presence and cite the alloy specification, rather than returning a blank form.

Is tungsten carbide tooling a conflict minerals issue for the parts I buy?

Tooling is not a constituent of the part, so it does not make the part reportable. The tooling supply chain has its own scrutiny, and some customers ask about it separately as part of supplier ESG review. Keep the two questions distinct, because conflating them creates confusion upstream.

What is the difference between the CMRT and the EMRT?

The CMRT covers tin, tantalum, tungsten and gold. The EMRT covers the same template structure for additional minerals, principally cobalt, and sometimes mica. Both come from the same industry initiative and share a layout, but they are separate submissions, and a customer asking for one may not have asked for the other yet.

Can we state that our parts are conflict-free?

Be careful with that phrase. "DRC conflict-free" has a specific meaning in the SEC framework, tied to documented due diligence on the specific supply chain. A shop that has not identified its smelters cannot support the claim. Describe what you know rather than adopting a phrase your evidence does not reach.

Related reading

• Supplier ESG Questionnaires: How a Small Machine Shop Answers2026-11-06
• Export Control and Machined Parts: ECCN, EAR99 and Deemed Export2026-11-05
• Comparing Machining Suppliers on Total Cost of Ownership, Not Price2026-10-29