The museum is dedicated to the preservation and display of relicts of the Slate industry in Wales.

The workshops which served the needs of the quarry and its locomotives, were built in 1870 on land created from the continuous tipping of spoil from the adjacent Vivian Quarry, and as a replacement for the store sheds which were previously sited there.

The museum reopened after receiving a £1.6 million grant from the Heritage Lottery Fund and now has displays featuring Victorian era slateworkers' cottages that once stood at Tanygrisiau, near Blaenau Ffestiniog.

The museum includes the multi-media display, To Steal a Mountain, showing the lives and work of the men who quarried slate here.

The museum also has the largest working waterwheel in mainland Britain, which is available for viewing via several walkways.