Austrian Mint

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TUNNEL CONSTRUCTION Tunnelbau Niobium Silver Bimetallic Coin 25€ Euro Austria 2013


One of the most mountainous countries in Europe, Austria has inevitably played a vital role in the development of tunnels. The brilliant ice blue 2013 addition to our innovative 25 euro Silver Niobium series pays homage to Austria’s long and influential contribution to tunnel construction. Comes in a case complete with a numbered certificate of authenticity and protective slipcase.

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Niobium, formerly columbium, is a chemical element with symbol Nb (formerly Cb) and atomic number 41. It is a soft, grey, ductile transition metal, which is often found in the pyrochlore mineral, the main commercial source for niobium, and columbite. The name comes from Greek mythology: Niobe, daughter of Tantalus since it is so similar to tantalum.
Niobium has physical and chemical properties similar to those of the element tantalum, and the two are therefore difficult to distinguish. The English chemist Charles Hatchett reported a new element similar to tantalum in 1801 and named it columbium. In 1809, the English chemist William Hyde Wollaston wrongly concluded that tantalum and columbium were identical. The German chemist Heinrich Rose determined in 1846 that tantalum ores contain a second element, which he named niobium. In 1864 and 1865, a series of scientific findings clarified that niobium and columbium were the same element (as distinguished from tantalum), and for a century both names were used interchangeably. Niobium was officially adopted as the name of the element in 1949, but the name columbium remains in current use in metallurgy in the United States.
It was not until the early 20th century that niobium was first used commercially. Brazil is the leading producer of niobium and ferroniobium, an alloy of niobium and iron. Niobium is used mostly in alloys, the largest part in special steel such as that used in gas pipelines. Although these alloys contain a maximum of 0.1%, the small percentage of niobium enhances the strength of the steel. The temperature stability of niobium-containing superalloys is important for its use in jet and rocket engines. Niobium is used in various superconducting materials. These superconducting alloys, also containing titanium and tin, are widely used in the superconducting magnets of MRI scanners. Other applications of niobium include its use in welding, nuclear industries, electronics, optics, numismatics, and jewelry. In the last two applications, niobium's low toxicity and ability to be colored by anodization are particular advantages.

  • CountryAustria
  • Year2013
  • Face Value25 Euro
  • MetalSilver
  • Fineness (purity)900/1000
  • Weight (g)16.50
  • Diameter (mm)34
  • QualityBU - Brilliant Uncirculated
  • Mintage (pcs)65.000
  • Certificate (COA)Yes
  • Presentation case (box)Yes

Opened in 1848, the vertex tunnel of the Semmering railway was the world’s first alpine tunnel. The ‘New Austrian Tunnelling Method’, which uses the geographical stress of surrounding rock to strengthen a tunnel, was developed from 1957 to 1965 and has since done a great deal to revolutionise tunnel construction around the world. A present-day tunnel boring machine features in the niobium pill of the coin’s obverse, its rotating motion symbolised by three arrows. The obverse’s outer silver ring shows the mountains through which the machine pierces. The coins reverse makes excellent use of the niobium pill to show one of the many road tunnels that pepper Austria’s alpine landscape today, while a tunnel worker uses a pneumatic drill to loosen rock in the silver ring alongside the word “Tunnelbau” (tunnel construction).

Minted to a maximum of 65,000 pieces in Special Uncirculated quality only, the coin contains 9 grammes of 900 Fine Silver in its outer ring and 6.5 grammes of 998 pure niobium. Each piece is encapsulated, boxed and comes complete with a numbered certificate guaranteeing its authenticity.