In 1743 Herbert Mackworth began mining at Onllwyn, with production rising with the opening of the Neath and Brecon Railway in 1864.

[2] However, at such depths and with frequent mining accidents due to methane gas and roof falls, the pit and it soon gained the unenviable nickname of "The Slaughterhouse."

[3] Nationalised by the National Coal Board, continual investment was required to combat the need to keep roadways open at the extreme depths.

A majority of the men were transferred to the new Blaenant drift mine, built to extract coal form the No.2 Rhondda seam at a shallower depth.

[4] The complete above ground mine workings remain intact on site, with the steam winding engine from No.2 shaft now electrically driven.

As well as artefacts from the mining industry, the museum also houses a restored and unique gas tram, which ran in Neath until 1920.