The venture was grossly overcapitalised and never really flourished. By 1879 it was clear the venture was not a success, and both quarry and railway were offered at auction on 9th October. No buyer was found, nor was one forthcoming at a second auction in March 1881, after which the property was bought personally by William McConnel, one of the original investors, for £18000. With the company’s finances restructured, the quarry expanded again, with a large new mill on Cantrybedd level and new underground levels and chambers.
William McConnel died in 1902 and the business was taken over by his son, W.H. McConnel. But with the leases on the land running out, there was little incentive to invest and on 17th December 1909 the men were told that the quarry was to close the next day. The remaining stocks were sent down the railway, and the machinery began to be dismantled.