Australia has two mints, the Royal Australian Mint (which also makes the country's circulating coinage) and the Perth Mint, which are both very active in the bullion coinage space; coins issued by them are legal tender. There are also private issuers of bullion, which is not legal tender and is targeted at investors and not at coin collectors.
This Perth Mint silver bar was extruded from a long strip of pure silver and chopped to weights of one hundred troy ounces. Edges are ground down to remove burrs and smooth the surface areas for a frosted finish. It features the Perth Mint's old (pre-2008) logo, weight and purity marks.
We lack information about when exactly these bars were produced.