I have written this blog about Australian circulating coins but the principle applies to other countries and currencies.
The Australian circulating coins are minted by The Royal Australia Mint (RAM) and are the coins you will find in your change. They are the coins (cash) used to buy and sell goods in the normal course of commerce.
The Perth Mint and occasionally other mints have minted coins for the Commonwealth of Australia during times of increased demand. Also the gold sovereigns were minted by various mints operating in Australia at the time.