Subject: File No. S7-40-10
From: Robert W Row

January 18, 2011

Why is only tantalum, and not niobium, considered by the SEC in its proposed conflict minerals rule as a derivative from the "conflict mineral", coltan (columbite-tantalite)?

According to TIC (Tantalum-Niobium International Study Center, see "'Coltan' is an abbreviation used only in parts of Africa for 'columbo-tantalite', it is a local name or nickname. Mineral concentrates containing tantalum are usually referred to as 'tantalite'. Columbite contains the element columbium, another name for niobium tantalite contains tantalum."

The proposed rules state on pages 11 and 12 that: "The Conflict Minerals Provision defines the term 'conflict mineral' as cassiterite, columbite-tantalite, gold, wolframite, or their derivatives, or any other minerals or their derivatives determined by the Secretary of State to be financing conflict in the DRC countries. Cassiterite is the metal ore that is most commonly used to produce tin, which is used in alloys, tin plating, and solders for joining pipes and electronic circuits. Columbite-tantalite is the metal ore from which tantalum is extracted. Tantalum is used in electronic components, including mobile telephones, computers, videogame consoles, and digital cameras, and as an alloy for making carbide tools and jet engine components. Gold is used for making jewelry and, due to its superior electric conductivity and corrosion resistance, is also used in electronic, communications, and aerospace equipment. Finally, wolframite is the metal ore that is used to produce tungsten, which is used for metal wires, electrodes, and contacts in lighting, electronic, electrical, heating, and welding applications." Niobium is not referenced in this key passage, or indeed anywhere else in the main text of the document.

According to the United States Geological Survey (see Table 6 of the 2008 Minerals Yearbook: Niobium (Columbium) and Tantalum Advance Release at, coltan from the Democratic Republic of the Congo yielded commercial sales of niobium as well as tantalum in each of the years on which it reports, 2004 through 2008.

Furthermore, as a Cabot Corporation simplified tantalum process flowchart (see Production Flowchart1.pdf) shows, a tantalum refinery designed by this major tantalum producer is set up to produce niobium as a by-product.

Amplifying this aspect of tantalum refining, the TIC states on its "Tantalum--Raw Materials and Processing" web page (see that "The extraction and refining of tantalum, including the separation from niobium in these various tantalum-containing mineral concentrates, is generally accomplished by treating the ores with a mixture of hydrofluoric and sulfuric acids at elevated temperatures. This causes the tantalum and niobium values to dissolve as complex fluorides, and numerous impurities that were present also dissolve. Other elements such as silicon, iron, manganese, titanium, zirconium, uranium, thorium, rare earths, et c. are generally present. The filtration of the digestion slurry, and further processing via solvent extraction using methyl isobutyl ketone (MIBK) or liquid ion exchange using an amine extractant in kerosene, produces highly purified solutions of tantalum and niobium. Generally, the tantalum values in solution are converted into potassium tantalum fluoride (K2TaF7) or tantalum oxide (Ta2O5). The niobium is recovered as niobium oxide (Nb2O5) via neutralization of the niobium fluoride complex with ammonia to form the hydroxide, followed by calcination to the oxide."

Finally, a check of suppliers offering coltan for sale on, the e-commerce site, reveals that at least some of them specify a niobium oxide concentration as well as a tantalum oxide concentration.

Given that it appears from the above that niobium is a commercial derivative of the "conflict mineral" coltan, the SEC's interpretation of the term "derivative" is not clear.

I suggest that the SEC defines in its final rule what a "derivative" of a "conflict mineral" is, that makes it clear why niobium is not considered a "derivative".