Perth Mint

The discovery of gold in large quantities in the early 1890s not only brought people and money into Western Australia, it left the government with the problem of how to handle all the precious metal being uncovered. There was very little cash in Perth for which miners could exchange gold, so the raw gold needed to be deposited somewhere.

In May 1894, the government applied to London for permission to establish a mint which could produce gold coins for use in the colony and elsewhere. At the time it was thought a mint that could produce £1,000,000 of coins a year would be adequate. The Imperial authorities responded positively, and sent a rough sketch showing the approximate number and size of the rooms required for dealing with that amount of coinage. This was passed to the local Government architect, George Temple Poole, who drew up plans for the Perth Mint.

The site chosen was in Hay Street, as the principal business thoroughfare of the city. Building commenced in 1896, and by December 1897 considerable progress had been made. However, by that time the gold yield of the colony had increased enormously, and it became evident the planned Mint would not be capable of dealing with the new situation. Alterations and enlargement of the buildings were commenced to provide space for the extra plant required. As a result, it took until November 1898 before the Mint’s buildings were finished, and until June 1899 before it could start operations to produce an estimated £3,000,000 of coinage a year.

The main building of the Mint, which faces Hay Street, was a stone-faced structure, roofed with Marseilles tiles. This building contained the offices and the residences of the two principal officers. Behind it were the various work-rooms, mostly brick or stone, roofed with galvanised iron. In front of the main building was a courtyard, and at the entrance gate, was a small lodge for the police guards.

The office for the receipt of gold was directly off the entrance hall where the precious metal would be weighed and a receipt given to the owner. After this, it was passed on to the melting house. This department occupied the western side of the building and contained fifteen furnaces, together with a small for carrying the heavy pots of molten gold to the moulds for casting into ingots.

All gold received at the Mint was melted and cast into an ingot. These were then analysed for purity so a calculation could be made of the amount of copper to be added to produce a standard sterling gold coin (11/12ths gold and 1/12th copper). The gold and copper were placed together in a crucible and melted once more. This was then cast into bars for making coinage, and these passed on to the next department

The coining room contained the rolling mill, cutting, and marking machines, blank washing apparatus, coining presses, and automatic balances. The bars were reduced to thin strips of metal between a very powerful pair of rollers to the exact thickness required. A cutting machine then produced discs (known as ‘blanks’) to a precise weight. However, the blanks were too hard to be stamped with the design of the coin, so they needed to be softened by being placed a metal cylinder and returned to a furnace.

In the coining press each blank was placed between two dies. The edge was milled at the same time, so both sides of the coin and edge was produced simultaneously. Sovereigns could be struck in the coining presses at the rate of about 80 a minute. Coins issued from the Perth Mint had a small ‘P’ on the design.

One immediate problem discovered at the new Perth Mint was that it proved difficult to weigh small samples of gold with the extreme accuracy required. Vibrations caused by traffic in the street and by the Mint’s own machinery meant that the more delicate weighings could only be safely conducted at night.

In 2003, the Perth Mint officially opened an 8,400 square metre state-of-the-art manufacturing facility next door to its original limestone building. It was here, in October 2011, that the world’s largest, heaviest and most valuable gold coin was struck. The coin is approximately 80 centimetres in diameter and 12 centimetres, and made of 1,012 kilograms of 99.99% pure gold. It is legal tender in Australia with face value $1 million, but at the time of minting it was valued at $53.5 million.

Today, the Mint continues to provide refining and other services to the gold industry and manufactures many coin related numismatic items for investors and coin collectors. It is also the oldest mint in the former British Empire to still be located on its original site.

Inquirer 2 October 1896

West Australian 21 June 1899

West Australian 28 February 1934