The answer will probably never be known. The Royal Australian Mint (RAM) Canberra opened in 1965. By 1984 had the sole responsibility for minting all of Australias circulating coins. Some coins had previously been minted by the Melbourne and Perth Mints and a few overseas Mints such as the Royal Mint and the Canadian Mint.
The Royal Australian Mint also produces coins for a number of other countries in addition to bullion coins, medals, medallions, tokens and other privately commissioned articles.
The Royal Australian Mint (RAM) has the production capacity to produce 2 million coins per day.
The original Australian decimal coins were designed by Stuart Devlin and mostly produced by the Royal Australian Mint Canberra.
The Royal Australian Mint produced no Australian Halfpenny coins from 1956 to 1958 inclusive.
The following information is from the Royal Australian Mint Annual Reports. In the 2007-2008 Financial Year, the Royal Australian Mint produced 196,685,000 Australian general circulation coins. In the 2008-2009 Financial Year, the Royal Australian Mint produced 167,600,000 Australian general circulation coins. The statistics for the 2009-2010 Financial Year are not yet available.
The Royal Australian Mint produced no Australian Halfpenny coins from 1956 to 1958 inclusive.
The Royal Australian Mint Canberra has produced over 13 Billion coins since it commenced production in February, 1965.
Since 1984, all of Australia's general circulation coins have been minted at the Royal Australian Mint Canberra. Prior to 1984, Australia's decimal coins were minted at the Royal Australian Mint Melbourne and the Royal Australian Mint Perth as well as the Royal Australian Mint Canberra. Very occasionally, some have been minted overseas at the Royal Mint London, the Royal Mint Wales and the Royal Canadian Mint.
The Royal Australian Mint produced 19.031 million standard cupro-nickel 50 cent coins.
The Royal Australian Mint (RAM) has the production capacity to produce 2 million coins per day. The Royal Australian Mint also produces coins for a number of other countries in addition to bullion coins, medals, medallions and other privately commissioned articles.
The Royal Australian Mint advises that from 1984 to 2009, approximately 754.246 million Australian One Dollar coins have been minted for general circulation.
With both the 1966 Australian "Proof" and "Mint" sets, sets labelled "Commonwealth of Australia" include 5, 10 and 20 cent coins minted at the Royal Mint London. With sets labelled "Royal Australian Mint", all coins were minted at the Royal Australian Mint Canberra.
Check the Royal Australian Mint site at the link below.
The Royal Australian Mint Sydney, was opened as a branch of the Royal Mint London in 1855 and closed in 1926. The Royal Australian Mint Melbourne, was opened as a branch of the Royal Mint London in 1872 and closed in 1967. The Royal Australian Mint Perth, was opened as a branch of the Royal Mint London in 1899 and is still operating. It is currently owned by the Western Australian Government and is responsible for producing most of Australia's bullion. The Royal Australian Mint Canberra, was opened in 1965 and is still operating. It produces all of Australia's circulating coins and mints coins for many other countries.