A new Cwmorthin Company was formed in 1876 following the collapse of the original company. To the north of the quarry, on the other side of the Allt-fawr ridge, the Welsh Slate Company, the Rhiwbryfdir Slate Company and Holland's Slate Company were all working the same veins. They were on land owned by the Oakeley family, and worked under leases, which placed restrictions on how they could be worked, and the royalties they had to pay. Cwmorthin was not restricted in this way, because they owned the freehold. The waste tips eventually covered Cwmorthin Isaf farmhouse, and the company and some of its workers built houses in Dolrhedyn, just above Tanygrisiau. On the surface, the boundary between the Oakeley's Tan-y-Bwlch estate and the Cwmorthin Isaf estate was marked by cast iron markers, which can still be seen, but below ground, the boundary was less clearly defined, and there were disputes over whether the companies were encroaching on each other's territory. This was resolved by an agreement in 1876, which survived several changes of ownership for the Oakeley Quarries, but following the death of Mary Oakeley in 1880, William Edward Oakeley got into financial difficulties, and the Oakeley Slate Quarries Company Limited was formed in 1884 to manage the quarries. Although a new agreement was drawn up between the Oakeley and Cwmorthin companies in 1884, Cwmorthin plans showed workings described as encroachments, and Oakeley plans showed trespass chambers ceded to Oakeley.