BRITISH COINS FROM OTHER PROPERTIES, Miscellaneous Trials and Proving Pieces, Royal Mint, Imperial Metal Industries and The Mint Birmingham Ltd, a series of Trials (6), based on the obv. of the Sierra Leone 10 Cents, 1964, and an enlarged version of the rev. of the Uruguay 5 Centésimos, 1960, bust of Sir Milton Margai right, royal mint trial around, revs. value in wreath, the original width of the design delineated by a linear border, all 23mm, viz. in pure nickel, z inside loop of 5 of value, edge plain, 4.95g/12h; in magnetic alloy, z inside loop of 5, edge plain, 4.90g/12h; in bright soft steel, i·m·i k·n·b inside loop of 5 [= Imperial Metal Industries Kings Norton Birmingham], edge plain, 4.68g/12h; another, similar, obv. with softer detail, edge plain, 4.63g/12h; in harder steel, i·m·i k·n·b inside loop of 5, edge security grained, 4.70g/12h; in hard steel, mbl above 5 and ha inside loop, edge finely grained, 3.19g/12h (KM. Sierra Leone TS1 and cf. KM. Uruguay PnB54) [6]. Last with some ghosting on reverse, otherwise all as struck, a very rare and unusual group (£120-150)

Provenance:
Joanna Tansley Collection, DNW Auction 67, 28 September 2005, lot 483, additionally:
*First Glendining Auction, 6 May 1987, lot 344
Third DNW Auction 33, 26 November 1997, lot 292, where described as aluminium in error
Fifth DNW Auction 52, 28-9 November 2001, lot 533
Two others bt Format November 1991.

These pieces, believed made in the late 1960s and certainly after the death of Sir Milton Margai (1895-1964), the first prime minister of independent Sierra Leone, are understood to form part of a wide series of trials and experiments into lower cost materials for coinage