Obverse. Photo © Austrian Mint
  • 25 Euro 2013, KM# 3217, Austria, Silver Niobium Coin, Tunneling
  • 25 Euro 2013, KM# 3217, Austria, Silver Niobium Coin, Tunneling
  • 25 Euro 2013, KM# 3217, Austria, Silver Niobium Coin, Tunneling, Box with a certificate of authenticity
Description

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 the innovative 25 euro Silver Niobium series pays homage to Austria’s long and influential contribution to tunnel construction.

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 revolutionize tunnel construction around the world.

Each coin contains 9 g of 900 Fine Silver in its outer ring and 6.5 g of 998 pure niobium. Each piece is encapsulated, boxed and comes complete with a numbered certificate guaranteeing its authenticity.

Niobium was chosen for the core due to its workability as a coinage metal and its low reactivity (which prevents its corroding where it comes in contact with the silver ring). Niobium’s larger application is in the aerospace industry, making it a thematic fit with the series, whose designs have focused on achievements in science and engineering.

Engraver: Herbert Wähner

Obverse

A present-day tunnel boring machine features in the niobium pill of the coin’s obverse, its rotating motion symbolized by three arrows. The obverse’s outer silver ring shows the mountains through which the machine pierces.

A tunnel boring machine (TBM), also known as a "mole", is a machine used to excavate tunnels with a circular cross section through a variety of soil and rock strata. They may also be used for microtunneling. They can bore through anything from hard rock to sand. Tunnel diameters can range from a metre (done with micro-TBMs) to 19.25 metres to date. Tunnels of less than a metre or so in diameter are typically done using trenchless construction methods or horizontal directional drilling rather than TBMs.

25
EURO
2013
REPUBLIK ÖSTERREICH

Reverse

The coin's 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).

TUNNELBAU

Edge
Characteristics
Type Commemorative Issue (Non-circulating)
Material Bi-Metallic
Ring Silver
Center Niobium
Weight 16.5 g
Diameter 34 mm
Thickness 2.55 mm
Shape round
Alignment Medal
Mint
Austrian Mint

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