On 6 December 1882 a major rockfall forced the Welsh Slate Company to shut down all operations. The instability in the mine continued, culminating in a much larger fall on 16 February 1883. This Great Fall saw 6.25 million tons of rock fall in a single event, severely damaging the workings. As well as the physical damage to the quarries, the fall triggered a lawsuit between the Oakeley Company and the Welsh Slate Company which the Welsh Slate Company lost. Unable to pay the resulting fine, the Welsh Slate Company gave up its lease and the Oakeley was finally amalgamated into a single operation.