Proof minting as practised by The Tower Mint is based on creating a bas relief sculpture and reducing the image down to size. The Company has developed its own distinctive house style which makes a feature out of the mirror finish background against a frosted relief, on its proof minted products.

Six traditional Janvier reducer die cutting machines are used to cut dies in-house, the control of this function is important in proof minting. Dies are then precision turned to fit the multistrike minting presses, and then case hardened, before being hand polished by craftsmen to match the mirror finish, which will appear finally on the struck products and medallions.

Blanks are prepared for the presses by individual polishing in custom built polishing machines, and thoroughly cleaned ultrasonically up to four times.

High tonnage knuckle presses strike the blank between the dies using a multiple strike process exerting a minting pressure of up to 360 tons per square inch. Each product is scrutinised for blemishes during the minting process.

Medals and coins can be produced in all forms of metals, including base metal, brass, nickel, silver and gold, hallmarked if applicable.

The Tower Mint's premises in SE London.