[3] The new mill contained four horizontal sandsaws driven by a steam engine, which was later replaced with a 30 feet (9.1 m) waterwheel.

A tramway was built across the Afon Lledr to connect the two quarries and slate from Chwarel Fedw was taken across to the second mill for processing.

[2] In 1877, 120 men were employed at Prince Llewellyn and the owner, George Raynes was looking to expand, and he purchased the Bwlch Gordduant quarry from Owen Gethin Jones.

[8] In 1882, the quarry employed 74 workers and produced 1685 tons of finished slate[2] under the ownership of George de Wolfe and Fisher Jones.

Mill worker Thomas Morris was pulled into one of the slate working machines when his clothes got caught in the drive strap.

[13] In 1909, the company was back in court after it failed to pay wages owed to its workers, and in December it was ordered to make good the missing money.

[1] Prince Llewellyn re-opened after the war and operated until 1934, and is thought to be the last mill to have used sandsaws[clarification needed] in the Welsh slate industry.