In the XVII century the processes for minting coins were mechanized and rolling mills, coining presses, etc., were installed. The new machinery and the demand on space in the Tower of London following the outbreak of war with France led to a decision to move the Mint to an adjacent site in East Smithfield. The new building, know as Tower Hill, designed by James Johnson and Robert Smirke, was completed in 1809, and included space for the new machinery, and accommodation for the officers and staff of the Mint.

The structure was rebuilt in the 1880s to accommodate new machinery which increased the capacity of the Mint. As technology changed with the introduction of electricity and demand grew, the process of rebuilding continued so that by the 1960s little of the original building remained, apart from the gatehouse in the front.

Δ  Exterior view of the New Royal Mint Building, at Llantrisant, showing the administrative offices, ca. 1969. The Mint Collection is stored within its premises. [1]

The Mint finally reached capacity ahead of decimalization in 1971, with the need to strike hundreds of millions of the new coins, while at the same time were not orders from overseas customers. In 1967 it was announced that the Mint would move away from London to new buildings in Llantrisant, 10 miles north west of Cardiff. The first phase was opened by Queen Elizabeth II on December 17th, 1968, and production gradually shifted to the new site over the next seven years until the last coin, a gold sovereign, was struck in London in November 1975. 

Δ  Facade of the former Mint today, where the 1½ pence coins were struck during its period of production 1834-1870. The building is now used as commercial offices by Barclays Global Investors. [2]

Δ  The coining room at the Royal Mint circa 1910, which was renovated in 1882 with installation of new machinery, seen here. However were not those used in the coinage of the 1½ pence coins.  [3]

The coining press was the most beautiful part of the whole mechanism in the production of 1½ pence coins by the Mint.

In 1805, the firm of Matthew Boulton [1728-1809] and James Watt [1736-1819], helped rebuild London’s Tower Mint, constructing all coining machinery and installing steam power. So efficient were his coining presses constructed at this time that they lasted seven decades until 1882, long outlasting the great innovator in the coin and medal field who died in 1809.

The coining-press-room, then, was about 70 feet in length, from 30 to 40 feet width, and its ceiling about 15 in height. It contains before 1870 eight presses, ranged in a straight line, on the vertical screw principle, as constructed in 1810, frequently at work for ten hours each day, and the destruction of eight pair of dies per run [one pair for each press] it could be considered a fair average result, though more frequently exceed that number of damaged dies.

When the run was completed, the dies were removed from the press. This procedure was repeated for each production run [often several production runs] in order to complete the orders.

My hypothesis is that each press produced about 3,600 pieces per hour, thus despite any mechanical problem, the daily production of each press was approximately in the range of 30,000 to 35,000 pieces; all coining presses together easily accomplished an average between 240,000 to 280,000 pieces within a whole journey of labor.

Δ  The engraving by artist Joseph Wilson Lowry shows the mechanism of the Boulton's screw coining press in its entirety, from the supplier apparatus of steam power at left, to the press in operation by an employee of the Royal Mint at right in 1866, used by the Royal Mint to strike more than 5.9 million 1½ pence coins between 1834 and 1870.  [4]

Δ  This table, using all the data collected, summarize the 1½ pence production of business strikes [1834 to 1862], with the coins production figure per calendar year ending December 31st, but not the amount struck of each specific date. For details visit each date page within the table that provide a LINK.

Traditionally, all coins struck at the Royal Mint have been dated the year of their coinage, although this didn't always happen. It's the case of the figures for coins for 1842 & 1843. 

Many mintage figures can be known with some certainty because documents that have surfaced and on the other hand the use of common sense when analyzing these data, however, this area warrants further study.

Δ   A table was published among the records of the Royal Mint in 1870 related to the actual minted figures of coins dated 1860 and 1862; the table was copied and reproduced, seven years later, in a document of the Government of the United States. Outlined in red, the relevant information related to the 1½ pence.  [7]

In the particular case of the coin production, the Chef and Assistant engravers of the Royal Mint, Sir William Wyon & Jean B. Merlen, played an important role in designing and manufacturing the dies and punches for the 1½ pence coin striking, thus next page is dedicated to them.